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Standardized Electrofishing Sampling “Where do I set the dials?”

Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

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Page 1: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Standardized Electrofishing Sampling ldquoWhere do I set the dialsrdquo

Presenter
Presentation Notes
This section will involve aspects of the equipment itself

Purpose amp Outline bull We will discuss the development and use of

electrical output goal tables for standardization

ndash Community of practice website electrofishingnet ndash Waveforms and their fish-catching attributes ndash Development and use of output goal tables

Electrical Waveforms

Description and Fish Catching Attributes

Main Types bull Direct Current (DC)

ndash or ldquoContinuous DCrdquo or ldquoSmooth DCrdquo

bull Pulsed Direct Current (PDC) ndash many forms

bull Alternating Current (AC) ndash many forms

Direct Current (DC)

bull Average voltage = Peak voltage

bull Average amperage = Peak amperage bull Average power = Peak power (volts x amps)

Advantages bull Typically causes attraction of fish to the anode bull Often less injurious especially with salmonids

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 2: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Purpose amp Outline bull We will discuss the development and use of

electrical output goal tables for standardization

ndash Community of practice website electrofishingnet ndash Waveforms and their fish-catching attributes ndash Development and use of output goal tables

Electrical Waveforms

Description and Fish Catching Attributes

Main Types bull Direct Current (DC)

ndash or ldquoContinuous DCrdquo or ldquoSmooth DCrdquo

bull Pulsed Direct Current (PDC) ndash many forms

bull Alternating Current (AC) ndash many forms

Direct Current (DC)

bull Average voltage = Peak voltage

bull Average amperage = Peak amperage bull Average power = Peak power (volts x amps)

Advantages bull Typically causes attraction of fish to the anode bull Often less injurious especially with salmonids

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 3: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Electrical Waveforms

Description and Fish Catching Attributes

Main Types bull Direct Current (DC)

ndash or ldquoContinuous DCrdquo or ldquoSmooth DCrdquo

bull Pulsed Direct Current (PDC) ndash many forms

bull Alternating Current (AC) ndash many forms

Direct Current (DC)

bull Average voltage = Peak voltage

bull Average amperage = Peak amperage bull Average power = Peak power (volts x amps)

Advantages bull Typically causes attraction of fish to the anode bull Often less injurious especially with salmonids

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 4: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Main Types bull Direct Current (DC)

ndash or ldquoContinuous DCrdquo or ldquoSmooth DCrdquo

bull Pulsed Direct Current (PDC) ndash many forms

bull Alternating Current (AC) ndash many forms

Direct Current (DC)

bull Average voltage = Peak voltage

bull Average amperage = Peak amperage bull Average power = Peak power (volts x amps)

Advantages bull Typically causes attraction of fish to the anode bull Often less injurious especially with salmonids

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 5: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Direct Current (DC)

bull Average voltage = Peak voltage

bull Average amperage = Peak amperage bull Average power = Peak power (volts x amps)

Advantages bull Typically causes attraction of fish to the anode bull Often less injurious especially with salmonids

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 6: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Advantages bull Typically causes attraction of fish to the anode bull Often less injurious especially with salmonids

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 7: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Direct Current 100 Duty Cycle

0 Volts baseline

Scopemeter graphic

Presenter
Presentation Notes
The simplest waveform is direct current (DC) that is output from batteries DC is on 100 of the time hence the 100 duty cycle DC requires a lot of energy and reduces battery discharge time relative to pulsed DC Capacitors are used to smooth or flatten the waveform

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 8: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Direct Current with Ripple

0 Volts baseline

By Spinningspark

The red line is continuous DC with a jagged top or ldquoripplerdquo Ripple is a result of smoothing fully rectified AC This waveform often is used in tow-barges with DC generators The ripple may enhance catchability and thus is sometimes exaggerated by the manufacturer

Presenter
Presentation Notes
The red line represents the actual waveform produced by a reservoir capacitor The dashed lines represent the fully rectified pulsed direct current waveform that was modified into the continuous DC Pulsed direct current is discussed next

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 9: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Drawbacks

bull May require slightly higher amperage than PDC for successful electrofishing

bull Also more energy consumptive thus the use of DC is restricted to a narrower conductivity range

bull Example for successful fishing of fish assemblages in nearshore Lake Superior the conductivity range was estimated at 35 ndash 320 microScm using a 2-boom metal hulled boat with an Infinity control box

bull Not available in all models

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 10: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Fish-Catching Considerations bull There are few adjustments possible with

continuous DC duty cycle is always 100 and frequency (pulses per second) does not apply

bull The adjustments are DC voltage and amperage so your strategy is simplified to building and using voltamp output goal tables for just one waveform

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 11: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Output Goal Table

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 12: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Pulsed Direct Current (PDC)

bull T

bull Pulse the part of the waveform during which voltage is present

bull Pulse width (PW) the time the pulse is on in milliseconds

bull Frequency the number of pulses per second (pulses per second)

bull Period (T) the time from the start of one pulse to the start of the next pulse

bull Duty cycle the ratio of ldquoonrdquo time (PW) to period (T) expressed as a percentage

- Duty cycle = (PWT) x 100 Note Peak Amps = Average Amps divide Duty cycle

Confuses many when changing from a GPP to a unit with peak reading meters

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 13: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Advantages bull Many waveform options (combinations of different

frequencies and duty cycles) bull May cause attraction of fish to the anode but not as

obvious as with DC bull Much less energy demanding than DC so can be

applied across a broader water conductivity range bull Generally more effective for capturing smaller

individuals than DC

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 14: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Pulsed Direct Current Square Wave

0 Volts baseline

Presenter
Presentation Notes
This is ldquosquare-waverdquo pulsed DC Many control boxes can output square-wave pulsed DC by chopping continuous DC with a high-powered switching transistor or an insulated-gate bipolar transistor 1313Calculation of pulse width or duty cycle of square-wave pulsed DC is simplified (pulse width can be measured at any height) Sometimes the pulse top will be slanted or have a leading spike This characteristic often appears when a unit is under heavier load in high conductivity water If the spike is accentuated the question of where to measure for peak voltage arises One recommendation is to measure peak voltage at the height where pulse width is one millisecond1313In this figure a 25 duty cycle means that the electricity is on 25 of the time

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 15: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Effect of Voltage on Wave Shape Smith-Root LR-24 Backpack

High loading can cause spiked pulses

Presenter
Presentation Notes
Note the formation of a ldquospikerdquo with higher voltage (power) levels1313Some models may hold the square pulse shape under greater loads more so than other models

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 16: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Scopemeter Tracings (Graphs)

Presenter
Presentation Notes
Duty cycle = time the electricity is on1313Frequency (pulses per second) is constant across the duty cycle range

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 17: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Pulsed DC Rounded Wave Mostly limited to GPPs and Type IV Models

0 Volts baseline

Half-Wave Rectified

Presenter
Presentation Notes
A common way to convert AC to pulsed DC waveforms is to half-wave rectify an AC waveform using a diode (rectifier) The resulting pulsed DC frequency is the same as the original AC frequency Many control boxes for boat electrofishers (such as the Smith-Root Inc GPP units) output this waveform shape Pulse width conventionally is measured at 50 of the pulse height

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 18: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Half-Wave Rectified

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current + Diode = Half-Wave Rectified DC

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 19: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 20: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
Page 21: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 22: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 23: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 24: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 25: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 26: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 27: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 28: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
Half-Wave Rectified
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 29: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
Full-Wave Rectified

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 30: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 31: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 32: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Chart2

Half-Wave Rectified
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 33: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
Page 34: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 35: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 36: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 37: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 38: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 39: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 40: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 41: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
Half-Wave Rectified
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 42: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
Full-Wave Rectified

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 43: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 44: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 45: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Pulsed DC Gated Burst

0 Volts baseline

Presenter
Presentation Notes
This waveform goes by different names ldquoComplex Pulse Systemrdquo or ldquoCPSrdquo (Coeffelt Manufacturing) ldquoQuadrapulserdquo (ETS Electrofishing LLC) ldquogated burstsrdquo and ldquoBurst of Pulsesrdquo (Smith-Root Inc)1313The original intent was to reduce injury potential while maintaining adequate catch rates Pulse packets are emitted at low frequency (to reduce injury) but inside the pulse packets are narrower high frequency pulses (for catchability)1313Pulse packet frequency usually is 15 pulses per second and higher whereas the pulses within packets usually come at frequencies over 200 pulses per second The number of pulses per packet are typically 3 ndash 5 There are 4 pulses per packet in the oscilloscope tracing above

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 46: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

PDC Drawbacks bull Often does not cause attraction response bull Almost an infinite number of waveform options

to choose from can lead to use of sub-optimal frequency and duty cycle combinations

bull May cause high rate of trauma especially in salmonids (for trout use le 30 pps)

bull Not as effective as alternating current in very low and very high water conductivity

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 47: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Fish-Catching Considerations bull Often 60 pps or 120 pps optimal for general catch efficiency higher frequencies

for capturing smaller fishes or if using a GPP unit so that a ldquorobustrdquo duty cycle is output

bull Lower frequencies (30 pps or less) used on salmonids to reduce injury rates bull Low frequency (15 pps) for blue and flathead catfishes in moderate conductivity

in very high conductivity (as near an estuary) ldquopulsed ACrdquo has been found to be effective

bull In colder water higher frequencies may be more effective on blues and flatheads bull Duty cycle range for general catch efficiency is 20 ndash 40 (can go down to 15

without much loss) 25 ndash 30 is the sweet spot bull Build volt and amp output tables as guidance for settings given water conductivity bull Square waves typically need less power applied then rounded waves bull Gated bursts (or CPS Quadrapulse pulse trains) were developed for reducing

injury in salmonids while keeping catch efficiency high more power is needed typically vs square wave PDC

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 48: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Alternating Current (AC)

bull AC Voltage (= RMS Voltage) is about 70 of peak in a sine wave (but electrofishing equipment rarely outputs a sine wave)

bull Same for RMS Current and RMS Power bull No constant anode and cathode (switching occurs at the frequency of the

generator (60 times per second in the US)

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 49: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Advantages bull Can be effective across a broad conductivity

range more effective than PDC in very low or high conductivity ndash This is because AC has higher voltage (Vpeak ndash Vpeak)

for low conductivity water and higher current (Amppeak ndash Amppeak) for high conductivity water

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 50: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Sine Wave

-12

-08

-04

00

04

08

12

0 90 180 270 360 450 540 630

Alternating Current Full Sine Wave

0 Volts baseline

Electrofishing gear output many different forms of AC The full sine wave is uncommon but one model example is the MLES Infinity control box

Presenter
Presentation Notes
All AC waveforms have positive and negative voltage excursions caused by switching between being the anode and the cathode at some frequency (commonly 50 or 60 Hertz [cycles per second]) Single-phase AC from commercial sources is a pure sine wave (eg from a wall outlet in your house)1313Often AC waveforms generated by electrofishing equipment are not in the form of sine waves Yet with positive and negative excursions they are still AC waveforms1313The 2 graphics on the right are taken from an oscilloscope screen and are from electrofishing gear the upper right is from a commercial unit and the lower right is from an illegal catfish electroshocker The grid is scaled vertically in volts and horizontally in time (milliseconds) For example in the upper right figure the scale is 100 V per vertical division and 2 milliseconds per horizontal division The upper right graph shows the waveform at a peak Voltage of 231 V Note that the oscilloscope scaling on the lower right graph is different The vertical scale is 50 V per division and the horizontal scale is 20 milliseconds per division The waveform in the lower right graph has a peak voltage of 107 V and a peak-to-peak voltage of 221 V

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 51: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Chart1

AC Sine Wave
0
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
122514845490862E-16
-01736481777
-03420201433
-05
-06427876097
-07660444431
-08660254038
-09396926208
-0984807753
-1
-0984807753
-09396926208
-08660254038
-07660444431
-06427876097
-05
-03420201433
-01736481777
-245029690981724E-16
01736481777
03420201433
05
06427876097
07660444431
08660254038
09396926208
0984807753
1
0984807753
09396926208
08660254038
07660444431
06427876097
05
03420201433
01736481777
367544536472586E-16

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
Page 52: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

SCR

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
X Sin X Sin X Sin X Sin X Sin X Sin X
0 0000 0000
10 0174 0174
20 0342 0342
30 0500 0500
40 0643 0643 0000
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985 0000
90 1000 1000 1000 1000
100 0985 0985 0985 0985
110 0940 0940 0940 0940
120 0866 0866 0866 0866 0000
130 0766 0766 0766 0766 0766
140 0643 0643 0643 0643 0643
150 0500 0500 0500 0500 0500
160 0342 0342 0342 0342 0342 0000
170 0174 0174 0174 0174 0174 0174
180 0000 0000 0000 0000 0000 0000
190 -0174
200 -0342
210 -0500
220 -0643
230 -0766
240 -0866
250 -0940
260 -0985
270 -1000
280 -0985
290 -0940
300 -0866
310 -0766
320 -0643
330 -0500
340 -0342
350 -0174
360 -0000 -0000
370 0174 0174
380 0342 0342
390 0500 0500
400 0643 0643 0000
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985 0000
450 1000 1000 1000 1000
460 0985 0985 0985 0985
470 0940 0940 0940 0940
480 0866 0866 0866 0866 0000
490 0766 0766 0766 0766 0766
500 0643 0643 0643 0643 0643
510 0500 0500 0500 0500 0500
520 0342 0342 0342 0342 0342 0000
530 0174 0174 0174 0174 0174 0174
540 0000 0000 0000 0000 0000 0000
Page 53: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

SCR

100 of Range

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 54: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Half Full

75 of Range

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 55: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Sheet2

50 of Range

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 56: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Sheet3

30 of Range
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 57: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
10 of Range
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 58: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
X Sin X Sin X Sin X
0 0000 0000 0000
10 0174 0174 0174
20 0342 0342 0342
30 0500 0500 0500
40 0643 0643 0643
50 0766 0766 0766
60 0866 0866 0866
70 0940 0940 0940
80 0985 0985 0985
90 1000 1000 1000
100 0985 0985 0985
110 0940 0940 0940
120 0866 0866 0866
130 0766 0766 0766
140 0643 0643 0643
150 0500 0500 0500
160 0342 0342 0342
170 0174 0174 0174
180 0000 0000 0000
190 -0174 0174
200 -0342 0342
210 -0500 0500
220 -0643 0643
230 -0766 0766
240 -0866 0866
250 -0940 0940
260 -0985 0985
270 -1000 1000
280 -0985 0985
290 -0940 0940
300 -0866 0866
310 -0766 0766
320 -0643 0643
330 -0500 0500
340 -0342 0342
350 -0174 0174
360 -0000 -0000 -0000
370 0174 0174 0174
380 0342 0342 0342
390 0500 0500 0500
400 0643 0643 0643
410 0766 0766 0766
420 0866 0866 0866
430 0940 0940 0940
440 0985 0985 0985
450 1000 1000 1000
460 0985 0985 0985
470 0940 0940 0940
480 0866 0866 0866
490 0766 0766 0766
500 0643 0643 0643
510 0500 0500 0500
520 0342 0342 0342
530 0174 0174 0174
540 0000 0000 0000
Page 59: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
AC Sine Wave
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 60: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
Half-Wave Rectified
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 61: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape
Full-Wave Rectified

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 62: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 63: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 64: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

AC Drawbacks bull Does not cause attraction response bull There are many AC waveforms (Triac ldquoAC Nerverdquo Full Sine and deviations

from full sine via changing duty cycle) bull Many forms are specific to particular models this can hinder fleet

standardization unless all boats or backpacks have the same model control box

bull Most volt and ammeters display RMS voltage or amperage this is OK if using a full sine wave because there is a relationship between RMS and peak (Peak voltage = RMS x 141) usually a full sine is not being output and thus you canrsquot use this relationship and thereby have to monitor peak outputs with external metering

bull Not available in all models (particularly backpacks) bull May cause high rate of trauma and injury

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 65: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Fish-Catching Considerations bull Some units have one form of AC others have

the capability to change the shape of the waveform (through changes in duty cycle) thus consider building voltamp output goal tables based on a particular form of AC this is the same case for pulsed DC as well ndash Most likely you will need external metering (as a

scopemeter) to monitor volts or amps

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 66: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Standardization Using Output Goal Tables

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 67: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Standardization Concepts bull The purpose of standardization is to reduce variability

in fish catchability (q) a more constant q helps CPUE data track population trends more accurately

bull Components to standardize include gear type electrode design waveform crew number crew experience dipnet mesh size sampling design (as day or night reach length) environmental conditions (eg temperature and discharge) and electrical output

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 68: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Output Goal Tables bull The standardization aspect we are going to cover

is electrical output goal tables ndash Peak Volts Peak Amps andor Peak Power

bull These tables are used for guidance for selecting voltage and current based on ambient water conductivity they can be strictly followed or used as a starting point (make trial runs near a sample site to fine tune settings)

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 69: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Output Goal Tables bull Output goal tables are specific to gear type electrode

design waveform target species or assemblages water body type (large reservoir shallow lake large river mid-sized stream)

bull Output goal tables are based on the power transfer model of electrofishing and require input of ldquothreshold datardquo (minimum voltage current or power needed to successfully sample a water body type) and an estimate of fish conductivity

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 70: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Inputs bull We often use a fish conductivity of 115 microScm bull Biologists should obtain threshold data and

develop their own tables using the Excel file EF Goal Power or the Electrofishing App

bull Protocols for gathering threshold data are at the end of this presentation

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 71: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Inputs bull If you do not have your own threshold data and want to build

tables here are some suggestions All outputs are at 115 microScm Backpack with ring anode and rattail cathode 1 amp 240 V Barge with one ring anode 25 amps 330 V Barge with two ring anodes 50 amps 390 V Boat with 2-boom Wisconsin-type anodes 10 amps 300 V bull Also see Table 2 in the blog ldquoFinal Electrofishing Field Blog in the

Seriesrdquo in electrofishingnet by Jan Dean

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 72: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Important Notes bull These tables may not be accurate enough for your

particular equipment or sample sites Try them and adjust as needed Wersquod appreciate feedback on your experiences using these tables or your output goal tables

bull Amperage is the best output to use for standardization (see recent blogs by Jan Dean) Using current as the output goal allows broader application to different electrode types However in low conductivity water or when using low power units as backpacks voltage may be a better choice to use instead of current

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 73: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Letrsquos Make Some Tables bull Use EF Goal Power

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 74: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Protocol to Use Tables in Sampling 1 measure ambient water conductivity (or specific

conductivity and water temperature and convert to ambient [see blogs on water conductivity and meters])

2 deploy electrodes in fishing fashion within typical habitat conditions for backpacks we suggest deploying electrodes as you would while sampling in about 1 - 15 depth

3 consult the goal table 4 standardize by volts or amps

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 75: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Protocol to Use Tables in Sampling 5 if you are using amperage then adjust voltage until the current goal is

reached as indicated on your gears peak ammeter 6 if you are using voltage adjust voltage until the voltage goal is reached

as indicated on your gears peak volt meter 7 if you have time to run a trial test go outside but near your sample area

and assess subjectively your electrofishing success if unsatisfactory adjust settings

8 record ambient conductivity threshold voltage or amperage used (preferably both outputs)

9 optionally record the major reaction of fishes (escape inhibited swimming attraction immobilization)

10 optionally record your assessment of the quality of the sampling such as successful or unsuccessful

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 76: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Protocol to Collect Threshold Data 1 Choose a waveform (AC DC PDC [frequency duty cycle])

and gear typeelectrode configuration 2 Take ambient water conductivity 3 Start at a low voltage setting 4 Begin electrofishing in a representative section of stream

or lake 5 Note fish reactions characterize the sampling as

ldquosuccessfulrdquo or ldquounsuccessfulrdquo describe fish reactions as ldquoescaperdquo ldquoinhibited swimmingrdquo or ldquoimmobilizationrdquo

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 77: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Protocol to Collect Threshold Data 6 If unsuccessful increase voltage (eg by 25 or 50 V) and follow steps 4 and 5

until the lowest voltage or current levels are found that result in successful electrofishing (threshold)

7 Once you have determined candidate threshold settings increase voltage (eg by 25 or 50 V) and note if sampling is the same if improved then your initial threshold estimate was too low if effectiveness appears the same or even declines then use your original threshold estimate you may change your threshold values depending upon fish recovery times (ie fish welfare)

8 (If successful on the first attempt go in reverse- reduce voltage (power) and sample again follow this procedure until successful electrofishing results)

9 If you cannot get to successful electrofishing change waveform type or PDC attributes(frequency or duty cycle) and start over with low voltage settings

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
Page 78: Standardized Electrofishing Sampling “Where do I set the dials?” … › monitoring › webinars › EF_Webinar_USGS2018.pdf · 2018-03-01 · the capability to change the shape

Protocol to Collect Threshold Data 10 Once you obtain successful electrofishing record -Ambient water conductivity (microScm) -Gear type (eg backpack model and electrode type and dimensions) -Voltage setting -Voltage output on meter (if available) -Current output on meter (if available) -Waveform type and attributes if PDC -Fish capture-prone response (escape inhibited swimming immobilization) -Water body type and size (eg for a stream at least mean width mean depth if possible)

  • Standardized Electrofishing SamplingldquoWhere do I set the dialsrdquo
  • Purpose amp Outline
  • Slide Number 3
  • Electrical Waveforms
  • Main Types
  • Direct Current (DC)
  • Advantages
  • Direct Current100 Duty Cycle
  • Direct Current with Ripple
  • Drawbacks
  • Fish-Catching Considerations
  • Output Goal Table
  • Pulsed Direct Current (PDC)
  • Advantages
  • Pulsed Direct Current Square Wave
  • Effect of Voltage on Wave ShapeSmith-Root LR-24 Backpack
  • Slide Number 17
  • Pulsed DC Rounded WaveMostly limited to GPPs and Type IV Models
  • Slide Number 19
  • Slide Number 20
  • PDC Drawbacks
  • Fish-Catching Considerations
  • Alternating Current (AC)
  • Advantages
  • Alternating Current
  • AC Drawbacks
  • Fish-Catching Considerations
  • Standardization Using Output Goal Tables
  • Standardization Concepts
  • Output Goal Tables
  • Output Goal Tables
  • Inputs
  • Inputs
  • Important Notes
  • Letrsquos Make Some Tables
  • Protocol to Use Tables in Sampling
  • Protocol to Use Tables in Sampling
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data
  • Protocol to Collect Threshold Data

Savick Brook Electrofishing Survey 2001

Savick Brook Electrofishing Survey 2001

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