Adult Steelhead Abundance Estimates Based on PIT Tag

Arrays in Idaho

Rick Orme,

Nez Perce TribeDepartment of Fisheries Resources Management

and

Chris Beasley and Jody White

Quantitative Consultants

The Integrated Status and Effectiveness Monitoring Project (ISEMP)

• Design, implement, test, and evaluate Status and Trends and Effectiveness Monitoring programs for salmon and steelhead populations and habitat.

• Determine whether innovative methods can be employed to increase the accuracy and precision of juvenile and adult abundance estimates at the subpopulation, population, and major population group (MPG) scales.

• Anadromous Monitoring Strategy: high precision abundance data for at least one population per MPG.

Background

• In-stream antennas

PIT Tag Array

Existing ISEMP arrays

Methods

Date

Num

ber /

Est

imat

e Estimated #Sampled &

Tagged

LGD sampling

- Systematic sample- Consistent sample rate

PIT tags

Population

Ratio(Expansion

Factor)

Methods

Population estimate using arraysArray 2

M = Marks C = CapturesR = Recaptures

Array 1

= MC/R ESCAPEMENT

Precision

Starting Population Estimate, (complex)

Estimated Number of PIT Tags

Escapement

Conversion

Percent TaggedEfficiency

Variables

4 levels

4 levels

5 – 99%

5 – 99%

Model

CV

= SE / Mean

Response Variable

Sample rate and adjustment, SbyC fish, August & December passages,fall back, --- adapt fall Chinook run reconstruction methodology

0.05

0.05

0.05

0.10

0.10

0.15

0.15

0.20

0.20

0.25

0.25

0.30

0.30

0.350.40

0.450.50

0.550.60

Efficiency of Array A0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Con

vers

ion

Rat

e (A

rray

A to

Arr

ay B

)

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Precision

Stream Escapement= 250

Tag Ratio= 15:1 (6.7%)

CV of Escapement

Precision

Percent of Population PIT Tagged0 2 4 6 8 10 12 14 16

CV

of E

scap

emen

t Est

imat

e

0.00

0.01

0.02

0.03

0.04

0.05

Num

ber of Recaptures

0

5

10

15

20

25

30

35

Escapement = 250Escapement = 2,000

Conversion = 90%Efficiency = 90%

• PIT Tags Representative of Population– Sub-sample (LGD)

• Systematic with a consistent sample rate

• Pre-array– Tag loss, tag induced mortality

• Mark-recapture– Mark loss, missed marks, equally capture prob., equal mortality,

random mixing, no additions, # recaptures

Assumptions

• Installed arrays in 2009• Initiated adult tagging fall 2009• Patiently waiting for adults

Project Status

Acknowledgments

BPA provided funding

Chris Beasley, Jody WhiteBill Young, Jason Vogel

3D9.1BF2328B203D9.QBF1641BB43D9.1UF1955DD23D9.1BE1970B603D9.1BFS9714443D9.1BF1TE288A3D9.1BF1AI19643D9.1BF232OD0D3D9.1BF2330NF03D9.1BF236AFS83D9.1BF23884D?3D9.1BF23A0EB4