POPULATION ASSESSMENT OF THE GULF OF MEXICO STURGEON IN THE

YELLOW RIVER, FLORIDA

By

JAMES JOSEPH BERG

A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT

OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2004

Copyright 2004

by

James Joseph Berg

iii

ACKNOWLEDGMENTS

I would like to extend my gratitude to Dr. Mike Allen for serving as my advisor

and committee chair, and helping me every step of the way. His dedication and guidance

throughout the course of this study are greatly appreciated. I would also like to thank Dr.

Chuck Cichra and Dr. Debra Murie for their guidance and for serving as members of my

committee.

I would like to thank my friend, Dr. Ken Sulak, for serving as committee cochair

and for his dedicated time, expertise and guidance in my research. Over the course of

this three-year study, he was able to experience first hand the power and ferocity of

Yellow River sturgeon, a different beast than the wimpy sturgeon found in the Suwannee

River. He gave me the opportunity to experience RoV, manned submersibles, research

cruises, Lophelia, and many wonderful research endeavors, although I did teach him (and

the rest of the CEC people) how to fish, so I guess we are even.

I would like to thank the United States Fish and Wildlife Service for funding this

project. The Panama City field office, specifically Frank Parauka, was a huge help and

offered advice and field services throughout the three-year study.

I would like to thank the United States Geological Survey in Gainesville, Florida,

for providing office space, field gear, boats, computers, field sampling help, and of

course my salary, as well as numerous trips to meetings worldwide.

Over the course of three years, the following people have offered advice,

participated in field work, gear maintenance, and anything and everything regarding the

iv

project that I needed. Without the following people from CEC, the project would not

have run so smoothly. I thank Cliff Bennett, Dr. Allen Brooks, Dr. George Dennis, Bill

Harden, Mike Randall, Jason Rochelo, Andrew Quaid, Dr. Phil Stevens, and George

Yeargin.

I would like to thank Dr. Bill Pine and Dr. Rob Bennetts who helped me with the

analysis and understanding MARK. Without Bill, I would still be trying to figure out

what the models were trying to tell me.

The following people made significant contributions to the data collection and field

work: M. Anderson, T. Bonvechio, P. Cooney, M. Friedman, S. Gooch, S. Keitzer, J.

Russell, S. Stahl, B. Tate, and K. Tugend.

The Northwest Florida Aquatic Preserves Office in Milton, Florida, has been a

huge help, lending us gear, people, and anything it had available that we needed. I would

like to thank everyone involved who helped us along the way including N. Craft, R.

Hinote, D. Holland, C. Jabaly, J. Jarrett, and B. Russell.

v

TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................................................................................. iii

LIST OF TABLES..............................................................................................................vi

LIST OF FIGURES .......................................................................................................... vii

ABSTRACT......................................................................................................................viii

CHAPTER

1 LIFE HISTORY OF THE GULF OF MEXICO STURGEON....................................1

2 POPULATION SIZE, GROWTH AND MORTALITY ESTIMATES FOR THE YELLOW RIVER GULF STURGEON POPULATION.............................................4

Introduction...................................................................................................................4 Methods ........................................................................................................................5

Study Site...............................................................................................................5 Fish Collection.......................................................................................................6 Aging .....................................................................................................................8

Analyses......................................................................................................................10 Population Size Estimation..................................................................................10 Tag Loss Estimates..............................................................................................12 Mortality Estimates .............................................................................................13

Results.........................................................................................................................15 Discussion...................................................................................................................18 Management Implications ..........................................................................................28 Future Research ..........................................................................................................29

APPENDIX CATCH DATA FOR THE YELLOW AND BLACKWATER RIVERS

(2001-2003) ................................................................................................................45

LIST OF REFERENCES...................................................................................................69

BIOGRAPHICAL SKETCH .............................................................................................77

vi

LIST OF TABLES

Table page 1 Reported total annual mortality rates for sturgeon species. .....................................31

2 A summary table for the Yellow River, Florida, Gulf sturgeon population estimate including capture probability and number of fish captured. ......................32

3 An age-length key created for the Yellow River age and catch data. ......................33

4 A table of all Gulf sturgeon that were captured in the Yellow or Blackwater rivers, Florida, that were initially tagged in a different river ...................................34

A-1 Catch data for the yellow and blackwater rivers (2001-2003) .................................46

vii

LIST OF FIGURES

Figure page 1 A map of the northern Gulf of Mexico with rivers inhabited by Gulf sturgeon

highlighted................................................................................................................36

2 A map and aerial photographs representing the Yellow River and Blackwater River, Florida, including the major sampling sites. .................................................37

3 Photograph of the two tag types used during this study. A T-bar tag is shown on top with a PIT tag underneath. .................................................................................38

4 An age bias plot of pairwise age comparisons between two agers for 92 fish.........39

5 Catch curve for Yellow River Gulf sturgeon based on number-at-age data collected during the summer and fall of 2001 .........................................................................40

6 The top chart is a length frequency histogram for Gulf sturgeon captured in the Yellow River, Florida, during 2001-2002, and the bottom is a percent frequency histogram of Gulf sturgeon captured in the Suwannee River, Florida during 2001-2002.................................................................................................................41

7 Von Bertalanffy growth model fit to observed length-at-age data for Yellow River, Florida, Gulf sturgeon, fall and summer 2001, and a von Bertalanffy growth model fit to observed length-at-age data for Suwannee River, Florida Gulf sturgeon. ...................................................................................................................42

8 Photograph of a 26.1-cm FL Gulf sturgeon captured in the Yellow River, Florida, approximately 3.5 km upriver of the Highway 90 bridge. .......................................42

9 A length frequency histogram for Yellow River, Florida, Gulf sturgeon captured during 2001. .............................................................................................................43

10 A length frequency histogram for Yellow River, Florida, Gulf sturgeon captured during 2002. .............................................................................................................43

11 A length frequency histogram for Yellow River, Florida, Gulf sturgeon captured during 2003. .............................................................................................................44

12 A 61.8 cm TL Gulf sturgeon captured on a fisherman’s catfish trot-line in Coopers Basin on the Blackwater River, found and released by my research team. .............44

viii

Abstract of Thesis Presented to the Graduate School

of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science

POPULATION ASSESSMENT OF THE GULF OF MEXICO STURGEON IN THE YELLOW RIVER, FLORIDA

By

James Joseph Berg

August 2004

Chair: Micheal S. Allen Cochair: Kenneth J. Sulak Major Department: Fisheries and Aquatic Sciences

The Gulf of Mexico sturgeon, Acipenser oxyrinchus desotoi, is an anadramous

species listed as threatened under the Endangered Species Act in 1991. The Gulf of

Mexico sturgeon is a subspecies of the Atlantic sturgeon, Acipenser oxyrinchus

oxyrinchus, and is found in coastal rivers of the Gulf of Mexico ranging from the Pearl

River, Louisiana, to the west and Suwannee River, Florida, to the east. I conducted a

three-year tagging study to estimate population size, growth, mortality and age

composition for sturgeon in the Yellow River. Capture probabilities and population size

were estimated using Program MARK and a Cormack-Jolly-Seber model. Total

mortality of Gulf of Mexico sturgeon was estimated using a Beverton-Holt mortality

equation and a catch curve. Growth rate was determined from annuli on the marginal

pectoral fin-ray. A total of 522 Gulf sturgeon captures were made, and 399 individual

fish were tagged. The population estimates for the Gulf sturgeon over three years ranged

from 500 – 911 fish, making the Yellow River population estimate the second largest for

ix

Gulf sturgeon. The age structure of the population suggests successful recruitment and a

viable population. Estimates of total annual mortality ranged from 8.5% to 12.5%.

Growth rate for the Yellow River population was comparable to other populations of

Gulf sturgeon. My data suggest that Yellow River Gulf sturgeon population is a dynamic

population based upon consistent age classes as an indicator of successful recruitment, a

large population size, and estimates of mortality below the reported range for the species.

1

CHAPTER 1 LIFE HISTORY OF THE GULF OF MEXICO STURGEON

Sturgeons are modern fishes descended from an ancient lineage, and fossil records

of sturgeon date back 200 million years. There are 25 species of sturgeon worldwide. Of

the nine species of sturgeon native to the United States, six have been given threatened or

endangered status by the Federal government. Sturgeon populations have declined due to

overfishing, habitat loss, and habitat manipulation. Vladykov (1955) separated Acipenser

oxyrinchus into Acipenser oxyrinchus oxyrinchus (Atlantic sturgeon) and Acipenser

oxyrinchus desotoi (Gulf of Mexico sturgeon). Atlantic sturgeon are found along the

Atlantic coast of the United States and Canada, whereas Gulf sturgeon occur in the Gulf

of Mexico and associated rivers. The only morphological difference between Atlantic

sturgeon and Gulf sturgeon is the relative length of the spleen (Wooley 1985). Genetic

work has reinforced that the Gulf sturgeon is genetically distinct from the Atlantic

sturgeon (Avise 1992; Lubinski et al. 1999; King et al. 2001).

The Gulf sturgeon is a federally threatened, anadromous species, listed under the

Endangered Species Act in 1991. Drastic declines in sturgeon populations caused the

State of Florida to prohibit commercial fishing for Gulf sturgeon in 1984 (Odenkirk

1991). Given low population abundances and marginal habitat quality in some systems,

assessment of Gulf sturgeon population characteristics is critical to recovery efforts.

According to the Gulf sturgeon Recovery Management Plan (USFWS, GSFC and NMFS

1995), estimates of Gulf sturgeon life history parameters (e.g., sex ratio, mortality,

2

recruitment, population size, and critical habitat parameters) are required for each

population so that informed management policies can be enacted.

Adult Gulf sturgeon migrate from the Gulf of Mexico into coastal rivers ranging

from the Pearl River, Louisiana, to the west and the Suwannee River, Florida, to the east

during early spring to spawn (Huff 1975; Chapman and Carr 1995; Sulak and Clugston

1998, 1999; Fox et al. 2000). There appears to be strong natal homing tendency, with a

minimum of four distinct sub-populations among rivers within the range of Gulf sturgeon

(Stabile et al. 1996). The four identified populations are the Pearl and Pascagoula rivers,

Escambia and Yellow rivers, Choctawhatchee River, and the Apalachicola, Ochlockonee,

and Suwannee rivers. Access to spawning grounds and protection of native riverine

habitats is vital to Gulf sturgeon populations.

Gulf sturgeon spawn on gravel substrate underlain by a light layer of sand and silt

(Sulak and Clugston 1998, 1999; Fox et al. 2000). Reproducing female sturgeon spawn

once every 2 to 4 years, though males spawn annually (Huff 1975). Spawning occurs in

early spring when females and males migrate upriver after overwintering in the Gulf of

Mexico. Sulak and Clugston (1999) estimated only 30 to 90 females a year were

spawning out of a total net-vulnerable population of 7,650 sub-adult and adult fish in the

Suwannee River, only 0.40% to 1.2% of the total population. Thus, Gulf sturgeon

population viability is highly sensitive to changes in adult female mortality and

abundance (Boreman 1997; Tringali and Bert 1998; Pine et al. 2001).

Post-spawning adults, subadults, and juvenile Gulf sturgeon remain in the rivers

throughout the summer months. During their stay in the river, Gulf sturgeon do not feed

and continue to lose weight (Mason and Clugston 1993; Gu et al. 2001). In the fall, Gulf

3

sturgeon are cued by unknown environmental factors and begin the fall emigration from

the river, which may occur over a two-month period (Carr et al. 1996b; Foster and

Clugston 1997). Although the cue is unknown, it seems not to be a single parameter, but

a combination of cues (e.g., moon phase, temperature, water flow). In the estuaries, Gulf

sturgeon feed intensively around mudflats and oyster bars on benthic prey (Mason and

Clugston 1993; Sulak and Clugston 1998; Harris 2003). Gulf sturgeon have been located

aggregating in the areas on the backside of coastal barrier islands and estuaries, in high

salinity Gulf waters (Edwards et al. 2003; Harris 2003).

4

CHAPTER 2 POPULATION SIZE, GROWTH AND MORTALITY ESTIMATES FOR THE

YELLOW RIVER GULF STURGEON POPULATION

Introduction

The Yellow River is located in the western Panhandle region of Florida,

approximately 40 km east of Pensacola (Figure 1). Minimal research effort has been

conducted on the Yellow River Gulf sturgeon population, and as a result, little is known

about the population of sturgeon inhabiting the river. To properly manage the population

and to ensure informed management decisions, all aspects of Gulf sturgeon life history in

the Yellow River need to be examined.

Population models are useful to examine trends and derive estimates of population

size. However, population size alone does not yield information on basic life history

parameters such as age structure, mortality, recruitment, and growth rates, all of which

are needed to fully understand the status of the population. Population models have been

used to estimate Gulf sturgeon population size and viability in the Suwannee River (Carr

et al. 1996a; Chapman et al. 1997; Pine et al. 2001), the Apalachicola River (Zehfuss et

al. 1999), and the Pearl River (Morrow et al. 1998) (Figure 1). The use of models to

estimate recruitment and mortality rates is necessary due to limited data from few years

of collection. Simulations show that Gulf sturgeon populations are sensitive to changes

in mortality and the percentage of females spawning annually (Boreman 1997; Pine et al.

2001; Tate and Allen 2002).

5

Individual growth and mortality rate estimates allow for comparisons among

populations, and are good indicators of population viability. A high mortality rate and

low growth rate indicate the population may not be viable. Habitat alteration, in the form

of anthropogenic disturbance of spawning site access with the possibility of a dam on the

Yellow River in the vicinity of 9 km upstream of the Highway 90 bridge, may be a

serious threat to the sturgeon population. Dams and low-level sills have impeded the

passage of Gulf sturgeon in other coastal Gulf rivers including the Apalachicola, Pearl

and Ochlocknee rivers. My objectives were to

1. obtain an estimate of population size for Gulf sturgeon >88.1-cm FL in the Yellow River;

2. examine age structure of the population; and

3. determine the rates of growth and mortality for the population.

Methods

Study Site

The Yellow River originates above Conecuh National Forest, Alabama, and flows

southwest into Blackwater Bay, near Robinson Point, Florida (Figure 2). The river basin

drains approximately 3,133 km2 (Florida Rivers Assessment 1989) and has a length of

196 km, of which 148 km are in Florida. The Yellow River is the fifth largest river in

Florida, with a mean annual discharge of 62 m3/sec (Florida Rivers Assessment 1989).

The Yellow River forms the northern border of Eglin Air Force Base across much of

Santa Rosa and Okaloosa counties and is classified as a Class III river (recreation,

propagation, and maintenance of healthy, well-balanced population of fish and wildlife)

by the Florida Department of Environmental Protection (DEP) (Florida Rivers

Assessment 1989). Current velocity in the Yellow River is faster than in many other

6

Florida rivers because it drains the state's highest elevations (Florida Rivers Assessment

1989). Upstream, large portions of the river are bordered by hardwood forest and high

sandy banks. These upriver sections are narrow, sandy bottom areas with high levels of

fallen timber and debris. Occasional lime rock outcroppings can also be found

throughout the upper reaches of the river. Downriver sections of the river are bordered

by cypress swamps that inundate and drain with changes in river stage during the wet and

dry seasons. Downriver, temperatures range from 14.06 to 27.41 degrees Celsius with

pH values of 6.39 to 7.78 throughout the year (USGS unpublished data). The Yellow

River joins the Blackwater Bay in four locations. The mouth of the river is constricted

by shallow grass flats and large fallen trees, alternate access to Blackwater Bay is

available through Weaver Creek, Skim Lake or Lindsey Pass.

Fish Collection

Sampling consisted of multiple tagging events throughout the summers of 2001,

2002, and 2003, and major recapture events during each of the fall emigrations of 2001,

2002, and 2003. Fishing was conducted using sinking gill nets, drift nets, or set nets as

applicable. Gulf sturgeon recruit to the nets used in this study at 88.1 cm fork length

(FL). The majority of the summer sampling was conducted using 45.72 m x 3.6 m

multifilament gill nets with a 0.1-m bar mesh or 45.7 m x 4.87 m nets with 0.1-m bar

mesh. Where necessary, a 91.4 m x 6.09 m with 0.17-m bar mesh multifilament gill net

was used as a set net. The majority of summer collection (>90%) was conducted using

drift nets. Drift netting allowed for active fishing and spatially locating sturgeon in their

summer areas.

During the fall of each year, Gulf sturgeon emigrate from the river, into the nearby

estuary and bay. Fall recapture events (fall census) were conducted during the

7

temperature range (17°-23° C) associated with the fall migration (Foster and Clugston

1997; Sulak and Clugston 1999). Two nets were utilized, a 91.4 m x 4.87 m with 0.1-m

bar mesh or a 91.4 m x 3.6 m with 0.1-m bar mesh multifilament gill net depending on

river stage and depth. Fall census nets were anchored from shoreline to shoreline except

for a small passage for boats navigating the river (near the shoreline). Fall census netting

was conducted at Cat Island Slough during 2001 (Figure 2). The 2002 collection event

utilized Cat Island Slough and a downriver site, Pine Bluff, as the set net areas, and the

2003 census location was the Pine Bluff site only (Figure 2). The fall census netting site

was moved due to shifting sand bars and changing depth in the river among years.

During the 2001 fall census, netting was conducted continuously 24 hours a day. A

multifilament gill net was set across the river as described above, and checked every

hour, only being pulled from the river on one occasion because of severe weather.

During the fall census in 2002 and 2003, nets were not soaked continuously for 24 hours

but instead were set between the hours of 1700 hours and 0800 hours Eastern Standard

Time based upon catch results from 2001, and checked at least once per hour.

During the summers of 2002 and 2003, sampling was conducted in the Blackwater

River using multifilament set nets to assess sturgeon migration between the Yellow River

and the Blackwater River. A 45.7-m x 3.6-m x 0.1-m or 45.7-m x 4.87-m x 0.1-m or

91.4-m x 6.09-m x 0.17-m multifilament gill net was used for collection.

Captured Gulf sturgeon were measured to the nearest 2-mm for fork length (FL)

and total length (TL) and weighed to the nearest 50 g. Gulf sturgeon were tagged once in

each pectoral fin with a T-bar style Floy tag (FD-9H, 25.4-mm mono Long-T) containing

a unique identification number for future recognition (Figure 3). Passive Integrated

8

Transponders (PIT) tags were injected into the dorsal musculature of each fish (Biomark

TX1405L, 14mm, 125 kHz) at the posterior dorsal fin base. After processing, all Gulf

sturgeon were immediately released alive.

Aging

During the summer and fall of 2001, subsampled fish had small sections of their

leading pectoral fin ray removed with a fine tooth saw (Cuerrier 1951; Cuerrier and

Roussow 1951) 15% of the total distance away from the point of articulation. Fish were

selected for fin-ray removal based on their size, and the number of fish of that size

already sampled. I kept the proportion of fish sampled for aging similar to the proportion

of fish from each size class to the overall population. This ensured the size and number

of fish selected for fin-ray removal would reflect the actual length-frequency distribution

of the sampled population.

The sections were placed into labeled vials and returned to the laboratory where

they were allowed to dry in open air. Fin samples were cleaned of excess epidermal

tissue under a dissecting microscope and three 0.25-0.45 mm transverse sections were cut

using a low-speed Isomet saw with a 12.7-cm diamond wafering blade to ensure at least

one would be readable. Sections made with the Isomet saw were stored in air, in labeled

vials, and read using a dissecting microscope (Olympus SZX 12) and transmitted light

(Cuerrier 1951) under variable magnification (8-20x). Although never validated for Gulf

sturgeon, formation of a pair of opaque and translucent growth rings were assumed to be

formed annually based on other sturgeon species (Brennan 1988, Brennan and Cailliet

1991; Rossiter et al. 1995; Stevenson 1997; Stevenson and Secor 1999). Translucent

areas were read as annual growth rings (Brennan and Cailliet 1989; Rien and

Beamsderfer 1994). Two independent readers estimated ages from fin ray samples

9

collected during 2001 (n=92) by counting rings along the radius of the section as

described by Roussow (1957) and Dadswell (1979). Huff (1975) and Stevenson and

Secor (1999), found that a completely formed marginal annulus was completely formed

in the fall for Gulf and Atlantic sturgeon. Based on these findings fin rays collected in

the summer with partial marginal annulus formation were assigned an age assuming the

partial annulus was complete. Fin rays collected in the fall were not advanced based on

marginal annulus formation. Ages were recorded by each reader and were only accepted

when there was reader agreement. A third independent reader was used to evaluate

discrepancies. If there was no consensus from the third reader, then the fin ray was

removed from the sample.

Precision estimates were calculated using the coefficient of variation (CV) as per

Chang (1982):

)(j

R

i

jij

jXR

XX

CV∑

−−

×= =1

2

1100 (1)

where Xij is the ith age determination of the jth fish, Xj is the mean age of the jth fish, and

R is the number of times each fish is aged. The results of the coefficient of variation

were averaged across fish to produce a mean CV. Age bias plots were constructed

between readers to examine the potential for systematic differences in the age readings

(Campana et al. 1995)

10

Analyses

Population Size Estimation

The most predominantly used capture-recapture model to study survival and

abundance is the Cormack-Jolly-Seber (CJS) model (Cormack 1964; Jolly 1965; Seber

1965). The model estimates apparent survival (φi) and recapture probability (ρi).

Apparent survival indicates loss of fish either to emigration or death (Williams et al.

2002). The CJS model assumes that all emigration from the study site is permanent.

Capture probabilities model the probability that an animal present in the study area at

time t is captured, and apparent survivability models the probability that an animal alive

at time t is still alive at t +1. There are six assumptions of the CJS model (Williams et al.

2002): 1) marks are never lost or misidentified; 2) animals are released after the sample,

and samples are of short duration; 3) individual capture events are independent between

individuals and capture times; 4) every individual has the same probability of being

caught, whether it is marked or unmarked; 5) every marked individual has the same

probability of surviving from the tth to the (t+1)st sample; and 6) changes in the

population occur only between the capture occasions.

I used a CJS-open-population capture-recapture model for estimating Gulf sturgeon

(≥ 88.1 cm FL) apparent survival (φi) and capture probabilities ( pi ) for summer and fall

sampling occasions (six sampling occasions) in 2001-2003. This model allows for

population changes (increases and decreases) due to emigration, immigration, births and

deaths between each sampling occasion.

All models were created and run in Program MARK (White and Burnham 1999).

Cormack-Jolly-Seber models in Program MARK use data constructed as capture

11

histories. Capture histories were inputted using a binary (0 or 1) coding system

constructed for each fish. The first “1” in a capture history indicates the fish was

captured and tagged, and any subsequent “1” indicates the fish was recaptured on another

occasion. A “0” indicates the fish was not captured. A capture history of “010010”

would indicate that this fish was not captured during the summer 2001 occasion, was

initially captured during the fall 2001 occasion, was not captured during the summer

2002 or fall 2002 occasions, was recaptured during the summer 2003 sampling occasion,

and was not recaptured during the fall 2003 occasion. For the purposes of my study, all

fish captured for the first time during this study were considered unmarked regardless of

previous tagging by other researchers.

Model selection was based on Akaike’s Information Criterion (AICc)(Akaike 1973;

Shibata 1989) in conjunction with knowledge of biological and life history

characteristics. The AICc values were adjusted for small sample sizes and over

dispersion (QAICc) (Akaike 1973; Burnham and Anderson 1998; Dreitz 2000). The

AICc term is a measure of deviation between the data and the model and therefore, the

model with the lowest AICc value represents the model that best fit the data. The lowest

AICc value does not mean that model is always the best model (makes the most

biological sense). It is the model within the set of run models that has the best support,

given the data, and therefore, it is important to consider biological characteristics and

knowledge of the species in question when you are considering model selection. A

variety of models were run that allowed apparent survival and capture probability to

remain constant, vary between seasons, or vary through time. Models that estimated

parameters between season grouped the summer 2001-2003 occasions under one set of

12

parameter estimates, and the fall 2001-2003 under another set of parameter estimates.

Based on estimates of mortality for the Yellow River from my study, apparent survival

was also fixed at 0.88 for some models. In total, 13 models were constructed and run

using Yellow River capture histories. Capture probabilities were the biggest concern for

this study, because capture probabilities are used on conjunction with the number of fish

captured for each sampling occasion to estimate population size. Biological and life

history characteristics were considered during final model selection to ensure selected

models did not report unrealistic estimates for capture probability and survival (i. e.,

capture probability of 100% or survival estimates of 10%). I used reported mortality

rates for sturgeon for comparison against the models (Table 1). Models reporting

mortality and capture probability rates that were unrealistic were not considered for final

model selection.

Population estimates (Ni) for Gulf sturgeon in the Yellow River were obtained

using the recapture probabilities ( pi ) estimated by the model, and the total number of fish

captured in each sampling occasion (Ci).

$NCpi

i

i= (2)

where Ni is the population estimate for sampling occasion i. Variance around these

estimates were calculated using Equation 1 with the reported 95% confidence intervals

for capture probabilities supplied by Program MARK.

Tag Loss Estimates

Tag loss is important to understand when mark and recapture data are used to

estimate population size (Robson and Regier 1966; Clugston 1996). To determine tag

loss for Gulf sturgeon in the Yellow River, I examined individual fish capture-recapture

13

data for the loss of one of the two T-bar tags over time in relation to presence of the PIT

tag. Recaptured fish with one missing Floy tag were recorded and their time-at-large was

noted. Studies have shown that loss of T-bar tags in sturgeon is directly related to time at

large (Clugston 1996). Tag loss was related to time-at-large using a logistic regression

(Miranda et al. 1997; SAS 2000; Henry 2002).

logit(l) = a + b1 (time), (3)

where logit(l) is the probability of tag loss, a is the intercept estimate, b1 is the parameter

estimate and (time) is the number of days-at-large. The logistic regression was weighted

for fish with multiple recaptures. Fish that were recaptured multiple times were entered

into the regression each time they were recaptured.

Mortality Estimates

Total mortality estimates were derived for Gulf sturgeon ≥88.1-cm FL in the

Yellow River. A von Bertalanffy growth curve was fit to the age-length data using non-

linear regression (SAS 2000) as:

Lt = L∞ (1-e-k(t-to)), (4)

where Lt is the fork length of the fish at time t, L∞ is the asymptotic length, k is the Brody

growth coefficient, t is age in years, and to is the age in years at length equal to zero if the

fish had always grown according to the von Bertalanffy growth equation. The resulting

equation was used in conjunction with a Beverton-Holt instantaneous mortality equation

to estimate instantaneous total mortality (Z) (Gulland 1983, cited in Pine et al. 2001) as:

Z =LcLxLxLk

−−∞ )( , (5)

where Lx is the mean fork length at capture, and Lc is the minimum fork length at which

Gulf sturgeon were vulnerable to capture.

14

The age data were also used to create an age-length key. An age-length key assigns

ages to fish of a certain size class, based upon the proportion of ages in the same size

class from the age data. The number of fish at each age over all sizes was summed to get

a total number of fish at each age. The resulting age-length key was used to assign an

age to each sturgeon that was measured but not aged directly, and create a catch curve.

The instantaneous total mortality was estimated by the slope of the descending limb of

the catch curve (Ricker 1975). Sturgeon were grouped into 4-cm size groups for analysis

with an age-length key and catch curve. Four centimeters was selected out of

convenience, due to the maximum FL of Gulf sturgeon and in an attempt to ensure each

size group contained age samples because of a low sample size. Ages 0, 1, 2 and 3 were

eliminated because these ages were not fully recruited to the sampling gear (Dadswell

1979).

Calculated instantaneous total mortality (Z) from the Von Bertalanffy growth

equation and catch curve were used to calculate percent total annual mortality (A) for

each method using the equation:

A = 1-e-Z (6)

I compared the size composition data from the Yellow River (2001 – 2002) to data

available for the Suwannee River for the same years (UF and USGS unpublished data).

To do so, I used a Chi-Square test to test for differences in the proportion of fish in three

size groups. The size groups were 85 – 134.9 cm, 135 – 179.9 cm, and 180 – 225 cm FL.

I used an alpha (α) value of 0.05 for the test.

15

To compare the growth equations of the two populations, I used a likelihood ratio

test as described by Haddon (2001) to determine if the parameters in the von Bertalanffy

growth equations differed for each population at an alpha 0.05.

Results

There were 13 sampling days during the summer of 2001, 13 in 2002, and 18 in

2003. The fall census period varied in length from September to October with 25 days in

2001, 22 in 2002, and 13 in 2003. A total of 522 Gulf sturgeon captures/recaptures were

made. Of these, 399 unique fish were captured and tagged, and 123 were recaptures.

The number of fish captured during each sampling period ranged from 40 to 101 (Table

2).

There were 11 sampling days in the Blackwater River during the summers of 2002

and 2003 in an attempt to quantify emigration (exchange between the Yellow River and

Blackwater River). Seventy-four captures of 69 unique Gulf sturgeon were recorded in

the Blackwater River. In the summer of 2002 a total of 48 Gulf sturgeon captures were

recorded, with 41 first captures, and seven recaptures of Yellow River fish. The 2003

sampling resulted in 19 first captures, and two recaptures, one of a Yellow River fish.

Five within season captures of Gulf sturgeon were made between the 2002 and 2003

sampling seasons.

The most parsimonious model, using a Cormack-Jolly-Seber in Program MARK

based upon the best fit AICc values, was the Φ(.) ρ(t) model. This model represented

constant survival [Φ(.)] and a time-dependent catch probability [ρ(t)], with an AICc value

of 684.4. The two models with the 2nd and 3rd lowest AICc values were the [Φ(t) p(t)] and

the [Φ(.) p(.)] models. These models returned corresponding AICc values of 688.4 and

689.4 respectively. For comparison, the [Φ(.) p(t)] model with apparent survival fixed at

16

0.88 returned an AICc value of 5647.2, the highest AICc value of all considered models.

Examination of the parameter estimates for the [Φ(t) p(t)] and [Φ(.) p(.)] models

eliminated them as adequate models, because the [Φ(t) p(t)] model returned capture

probabilities of 96%, which was unrealistic for this study or this species, and the [Φ(.)

p(.)] model only allowed for one estimate of capture probability for the entire study,

which is unrealistic given the data. The model with the lowest AICc value did not report

unrealistic parameter estimates. Capture probabilities ranged from 0.05-0.17 between

sampling periods (Table 2). Population estimates, for each occasion based upon the

capture probabilities, ranged from 500 to 911 across time periods (Table 2).

To correct estimates for tag loss, logistic regression was used to determine the rate

of tag loss based upon time-at-large, but the relationship between tag loss and time-at-

large was not significant. I recorded only 16 instances of fish losing one T-bar tag and 4

instances of fish losing both T-bar tags. Three fish were recaptured during the study with

missing PIT tags. However, in all cases of T-bar tag loss, fish retained their PIT tags.

Therefore, I did not correct for tag loss in my analysis. I do not believe any fish lost all

three tags, because we did not capture fish that showed signs of previous tagging without

having one tag still present.

Sections of the leading edge of the pectoral fin-ray were removed from 92 Gulf

sturgeon during the summer and fall of 2001 for aging back at the laboratory. Fish

ranged in size from 80.5 cm FL to 184.4 cm FL, and 2 to 20 years in age. However,

because I effectively captured fish only ≥ 88.1 cm FL, fish less than 88.1 cm FL were not

used in the age analysis. Precision of between reader age estimates was calculated to be

3.357% using the coefficient of variation. The age bias plot shows that slight age under

17

estimation bias is present (Figure 4). For analysis, 87 fish were used, ranging in age from

3 to 20 years. A von Bertalanffy growth curve was fit to data for the Yellow River

population of Gulf sturgeon (Figure 7):

Lt=180.3 (1-e-0.1681(t+1.5711)) (7)

Estimates of instantaneous total mortality (Z) based on a Beverton and Holt

mortality equation using data from Eqn (5), based on Eqn (7) was -0.126 and the estimate

of percent total annual mortality (A) was 11.88%.

The von Bertalanffy growth equation was used for the Suwannee River as reported

by Pine et al. (2001):

Lt=222.2 (1-e-0.08142(t+2.18)) (8)

Results of the age-length key can be seen in Table 3. Instantaneous total mortality

(Z) from the catch curve (slope of the regression) was -0.089 (Figure 5) and the resulting

total annual mortality rate was 8.5%. Number-at-age data were used from the age-length

key for catch curve analysis, but lengths were variable at any given age, and some ages

were under-represented (Table 3).

The proportions of fish in each size class differed (X2=23.16, df =2, p=0.001)

between the Yellow River and Suwannee River populations. In the Suwannee River,

56.4% of fish were 85-134.9 cm FL, 41.6% were 135-179.9 cm FL, and 1.8% were 180-

225 cm FL (Figure 6). The proportions of each size group in the Yellow River were

40.8%, 52.3%, and 6.9%, respectively (Figure 6). The likelihood ratio test showed that

there was a significant difference between the von Bertalanffy growth equations for the

Yellow River and Suwannee River populations of Gulf sturgeon (X2=54.15, df =3,

p=0.001) (Figure 7). There were significant differences between the growth coefficients

18

(k) (X2=6.02, df =1, p=0.014) and to (X2=5.38, df =1, p=0.020), and slight significance in

asymptotic length (X2=3.41, df =1, p=0.065).

Discussion

My estimates of the Gulf sturgeon population size for fish ≥ 100 cm TL were

greater than or equal to 500 individual fish for each sampling period and each estimate

was within the confidence intervals of all other estimates, except for the summer 2002

sample and the fall 2003 sample. The summer 2002 sample had an upper confidence

limit of 816 while the lower limit for the fall 2003 sample was 550 (Table 2). In general,

the estimates for each sampling period increased over the three years. This increase

resulted due to recaptures of fish that were at large since initial tagging in 2001. I

recaptured multiple fish during the summer and fall of 2003 that had not been

encountered since they were initially tagged in the summer and fall of 2001. The

resulting capture histories for these fish caused the model to recognize that they had not

necessarily died, but simply had not been recaptured.

My data suggest that the Yellow River supports the second largest population of

Gulf sturgeon (319-1,550). Population estimates for Gulf sturgeon are only available for

the Suwannee, Apalachicola, and Pearl river systems, and the estimates from the

Apalachicola River only estimate the population below the Jim Woodruff Lock and Dam.

Zehfuss et al. (1999) estimated the population of Gulf sturgeon in the Apalachicola River

to be 62-218 individuals. The Pearl River was estimated to have 292 individuals, over

age three (Morrow et al. 1998). Estimates for the Suwannee River net-vulnerable (>100

cm TL) subadult/adult population are much higher and have been conducted on four

occasions. Carr et al. (1996b) estimated the population to be between 1,504 and 3,066

fish. Chapman et al. (1997) presented a higher estimate of 2,097 to 5,312 fish. Sulak and

19

Clugston (1999) estimated the population at 7,650 total individuals, and Pine et al. (2001)

estimated the population at 5,500. The large variation among population estimates on the

Suwannee River are due to the manner of sampling in each study. Carr et al. (1996b) and

Chapman et al. (1997) sampled the returning adult and sub-adult populations each spring,

and had few recapture data. Sulak and Clugston (1999) had a large number of recaptures,

encompassing a longer time frame and a broader range of mesh sizes.

The assumption that emigration is permanent during sampling occasions was

violated during the course of this study. Gulf sturgeon immigration and emigration in the

Yellow River was apparent over the three-year study. Natal homing capabilities have

been extensively studied for salmonid species. The range of natility in salmon is 80-

100%, and percentage of fish straying for most populations is believed to be 2-5% based

on hatchery fish (Hasler and Scholz 1983). Earlier work in the Yellow River showed that

Gulf sturgeon tagged in the Yellow River were sometimes relocated in the Blackwater

River system and as far away as Louisiana (Craft et al. 2001). Sampling in the

Blackwater River was conducted to assess the amount of emigration from the Yellow

River into the Blackwater River. Eight fish, tagged in the Yellow River during this study,

were recaptured in the Blackwater River, and 23 instances of immigration into or

emigration from the Yellow River were documented over the three-year study, not

including seven fish of unknown origin (Table 4). Data from USFWS also shows that

fish tagged in the Yellow River with acoustic tags have been relocated in other river

systems (Frank Parauka, USFWS, personal communication). River interchange has been

documented by other researchers throughout the Gulf of Mexico (Carr et al. 1996b; Craft

20

et al. 2001; Fox and Hightower 1998; Dugo 2003; Frank Parauka, USFWS, personal

communication; Ken Sulak, USGS, personal communication).

One problem associated with interchange between river systems is determining the

sturgeon’s true natal river. River transfer data from my study suggests that sturgeon

move between rivers. A fish tagged initially in the Choctawhatchee River and relocated

in the Yellow River may actually be a fish spawned in the Yellow River which happened

to be captured for the first time in the Choctawhatchee River system. The amount of

inter-river exchange documented in the Yellow River over three years may indicate fish

in the Panhandle (i.e., Choctawhatchee River to Pearl River) act as one large population.

However, Stabile et al. (1996) and Dugo (2003) report that the Choctawhatchee River,

Escambia River, and Yellow River populations of Gulf sturgeon are genetically distinct

from one another. Relatively high rates of interchange between the Blackwater River and

Yellow River, as well as their close proximity, suggests that Gulf sturgeon in these two

rivers may regularly interbreed. Limited sampling has been conducted on the Escambia

River but ongoing tagging studies by the USFWS will shed light on the role of the

Escambia River in relation to the Yellow River. Tag-recapture data from this study, as

well as telemetry data from Craft et al. (2001), show that some fish moving upriver

during the spring spawning migration drop downstream and relocate to different rivers

later during the same spring or summer. Gulf sturgeon in this area may have the option

of changing rivers during the spring if spawning conditions are not suitable in their target

river.

Temporary emigration can have a large impact on the estimates from population

models (Burnham 1993). The population estimates for the Yellow River may be

21

positively biased (overestimated) if the system experiences high rates of temporary

emigration. Zeufuss et al. (1999) conducted simulations to determine the impact of

temporary emigration on their estimates in the Apalachicola River system. In situations

with random temporary emigration where capture probabilities were high (≥0.50), they

showed that population size could be estimated with no bias. However, low capture

probabilities resulted in underestimates of population size when Markovian emigration

(fish remember they have left the study area) was occuring.

Tag loss was to be accounted for in each of the sampling occasions based on time-

at-large for each captured fish because high rates of tag loss would have an impact on the

population estimates due to the inability of the researchers or the model to recognize the

actual identity of fish with lost tags. If tag loss was occurring, tagged fish would not be

recognized as previously being tagged and would be counted as new or virgin fish. This

decrease in apparent recaptures would result in a decrease in survival estimates, and may

result in an overestimate of population size. Studies have shown PIT tag retention rates

to be 90-100% (Jenkins and Smith 1990; Prentice et al. 1990; Smith et al. 1990; Clugston

1996) and T-bar tag loss has been shown to be related to time-at-large (Clugston 1996).

Tag loss was examined in this study using logistic regression, but the relationship

between T-bar tag loss and time at large was not significant. One explanation may be the

combination of small sample size and low number of recaptures. It was unlikely that

sturgeon tagged during this study would lose all three tags, and thus, tag loss was

considered insignificant.

The total annual mortality estimates for Gulf sturgeon in the Yellow River were

lower than the reported range for this species, and within the reported range for other

22

species of sturgeon (Miller 1972a; Huff 1975; Kohlhorst 1980; Dadswell 1979; Devore et

al. 1995; Beamesderfer et al. 1995; Stevenson 1997; Bruch 1999; Sulak and Clugston

1999; Pine et al. 2001) (Table 1). Due to the commercial fishing ban in 1984 for Gulf

sturgeon in Florida, my mortality estimates for the Yellow River should only be dealing

with natural mortality. The catch curve resulted in an estimate of 8.5% total annual

mortality (Figure 5). This mortality rate is lower than the mortality estimate from the

Beverton and Holt equation of 11.8%. Due to a low sample size, under-represented (< 5

fish) age classes were present, but had to be included in the catch curve. I have less

confidence in the catch curve estimate due to low sample size, missing year classes and

high variation in length-at-age data (Table 3). The high variation in length-at-age for

Gulf sturgeon makes them a poor candidate for estimating age structure with an age-

length key. For example, fish ranging in size from 172-175.9 cm FL ranged in age from

10-20 years in age (Table 3).

The age bias plots between readers shows that there was slight bias present, most

likely due to the difficulty in assigning ages to older fish. The major problem

encountered in older fish was crowding of annuli, which is not uncommon for long-lived

species (Huff 1975; Dovel and Berggren 1983; Brennan and Cailliet 1989; Rien and

Beamesderfer 1994, Laura Jenkins, USFWS, personal communication). Age precision

(CV) for Yellow River Gulf sturgeon pectoral fin rays was 3.357% between readers.

This is lower than reported by Stevenson and Secor (1999) for Atlantic sturgeon (4.5%),

and by Rien and Beamesderfer (1994) for white sturgeon (7.8%), although, it is within

the range of reported values for other species (Rien and Beamesderfer 1994; Stevenson

and Secor 1999). However, Stevenson and Secor (1999) and Rien and Beamesderfer

23

(1994) were dealing with longer-lived sturgeon species and increased ages may be

responsible for less precise age estimates.

Inaccurate age estimates for any species, including Gulf sturgeon can cause

problems for resource managers (Archibald et al. 1983; Leaman and Nagtegaal 1987;

Rien and Beamesderfer 1994; Pine et al. 2001; Tate and Allen 2002) because

underestimating the age of sturgeon can affect estimates of life history parameters and

population dynamics. Fin ray sections in this study were removed at 15% from the point

of articulation, resulting in some loss of annuli. Underestimating the ages of Gulf

sturgeon could result in over-estimates of mortality and growth for the population. In

white sturgeon, ages determined from pectoral fin rays underestimate the true age of large

fish (Rien and Beamesderfer 1994; Paragamian and Beamesderfer 2003). Management

decisions regarding sturgeon are in part influenced by estimates of population parameters

(ie., size, mortality, growth) supplied by researchers (Dadswell 1979; Smith 1984; Smith

and Clugston 1997), and care must be exercised.

Based on the number of large sturgeon in the river, the estimates of population

size over three years, and the capture of age-0 sturgeon, the Yellow River Gulf sturgeon

population seems to be a viable (i.e., regularly reproducing) population. The population

produces offspring with the capability of reproducing, and the population seems to be

stable under the present conditions, although three years may not be sufficient to

recognize changes in population size. The catch data were skewed towards larger fish,

which is most likely not attributable to gear bias because the mesh size used in this study

effectively captures any fish over 88.1 cm FL. Although our nets were not targeting fish

smaller than 100 cm TL, we captured 15 fish in the Yellow River <100 cm TL, the

24

smallest being only 80 cm TL. However, a 30.5-cm (young-of-the-year) Gulf sturgeon

was collected by USGS using an electrofishing boat. Thus, age 0-1 fish were present,

indicating successful reproduction at some level. However, attempts to capture eggs at

probable spawning locations in the Yellow River through use of egg pads have been

unsuccessful to date (USGS unpublished data). The Yellow River experiences a great

variation in springtime river conditions which makes it difficult to sample for eggs. High

water and fast currents do not allow for easy access and maneuverability in the upriver

sections of the river where spawning most likely occurs. High water is often followed by

extreme low water creating log jams and exposing the river bottom making navigation

impossible.

Nevertheless, three age-0 Gulf sturgeon have been collected on the Yellow River

(Philip Kilpatrich, Alabama Game and Fish, personal communication, USGS unpublished

data). Two of the collected fish were ~ 15.0 cm TL and were captured near “Dripping

Rock” in Alabama. Fish of this size were undoubtedly spawned in the Yellow River,

since larvae and juveniles of most sturgeon species are intolerant of salt water (Jenkins et

al. 1993; McCabe and Tracy 1994; Kynard 1997; Sulak and Clugston 1999). It is highly

unlikely these age-0 fish were spawned in a nearby river and traversed Blackwater Bay to

reach the Yellow River. In November of 2003, another age-0 sturgeon measuring 26.1

cm FL was collected by USGS ~ 3.5 km upriver of the Highway 90 bridge (Figure 8).

This approximately 7 month old fish offers the first photographic proof that spawning

occurs in the Yellow River.

Although there is an apparent difference in Gulf sturgeon length frequencies

between the Suwannee River and the Yellow River, the maximum TL (~225 cm)

25

reported for other rivers (Fox and Hightower 1998; Morrow et al. 1998; Slack and Ross

1998; Slack et al. 1999; Fox et al. 2000), including the Suwannee (Sulak and Clugston

1999; Sulak and Randall 2002), is the same as the Yellow River. Reasons for the

differences in size may be related to one of three possibilities: 1) selective adaptation due

to selective harvest; 2) differences in population parameters (i.e., mortality, growth,

recruitment, sex ratio); or 3) mix of successful year classes for point-in-time snapshots of

the respective river populations.

Differences in commercial fishing efforts between rivers may have contributed to

differences in size structure between populations. The Suwannee River was fished

commercially for nearly 100 years (Hoover 2002). During the period of commercial

fishing, effort was concentrated during the spring when Gulf sturgeon were migrating

into the river to spawn. A century of commercial fishing, and the removal of large

breeding males and females, may be responsible for genetically selecting for smaller fish.

While 100 years of fishing would only allow for four generations of large breeding males

and females, impacts of selective harvest have been shown for other fish species in fewer

generations. In salmon hatcheries, where natural selection is relaxed, the overall size of

salmon eggs has rapidly decreased, and smaller egg sizes are found in wild populations

heavily supplemented by hatcheries (Heath et al. 2003). Multiple studies have noted the

reduction of length-at-age, length-at-maturity, age-at-maturity, and growth rates for fish

species exposed to size-selective harvest (Harris and McGovern 1997; Heino 1998; Chen

and Mello 1999; Haugen and Vollestad 2001). In some cases, after selective harvest was

ended, some of these life history parameters began to increase. However, Conover and

26

Munch (2002) warn that genetic changes in a population from selective harvest may be

irreversible.

Differences in population parameters may be responsible for the greater numbers of

large fish found in the Yellow River. The reported mortality rates for the Suwannee

River Gulf sturgeon (ages 4 to 25) are 16-17% (Sulak and Clugston 1999; Pine et al.

2001). These estimates are considerably higher than the mortality estimates found in the

Yellow River (11.8%). Yellow River Gulf sturgeon experience faster growth between

the ages of 3 to 15, based on the likelihood ratio test, and there are fewer older fish in the

Suwannee River population. Lower mortality and faster growth in the Yellow River,

may be responsible for the larger fish size.

Sex ratio is an important dynamic of the population to consider when making

comparisons between different populations. The sex ratio for the Suwannee River

population is reported as 50:50 (Huff 1975). Minimal data has been gathered on the sex

of fish in the Yellow River, and was not examined during this study. A higher ratio of

females to males in the Yellow River may explain the differences in the proportions of

large fish in the Yellow River compared to the Suwannee River, due to sexual dimorphic

growth. If the Yellow River population is composed of a high proportion of large,

reproductive females, it would have significant management implications. I did not

measure the fecundity or sex ratios for the Yellow River population, but the proportion of

large fish in the population indicates potential for increased reproductive capacity relative

to the Suwannee River population, which warrants further investigation.

A third alternate explanation is that the length/age frequency observed in the

Yellow River during each year is simply an instantaneous picture of population

27

dynamics. Years of successful and unsuccessful recruitment can create modes in the

length/age frequency structure of a population. In the Suwannee River, Sulak and

Clugston (1999) showed that length/age frequency structure in any given year was

controlled by strong and weak year classes. Over time, as those year classes grew, they

progressively changed the length/age frequency structure of the population. Therefore, it

could be hypothesized that the higher proportions of large fish in the Yellow River during

this 3-year study period was due to successful year classes dominating the population in

the years sampled. On average, fish in the Yellow River live longer than fish in the

Suwannee River. However, except for one occasion, fish in both populations reach a

maximum age of ~ 25 years (Huff 1975; Sulak and Clugston 1999; Pine et al. 2001;

Sulak and Randall 2002).

Sampling during 2001 yielded a length/age structure indicating a subadult/adult

population with two dominant modes (Figure 9), one at ca 135 - 140 cm FL (= ca 7 - 8

years old) and another at ca 160 – 170 cm FL (= ca 12 - 17 years old). A valley exists at

ca 150 cm FL (= ca 10 years old), indicating weak recruitment. Examination of the catch

data for 2002 (Figure 10) and 2003 (Figure 11) shows a similar pattern of two major

dominating modes and corresponding valleys. The valleys and peaks are not signs of

population growth or decline, but of relative strength of recruitment to the year-classes

contributing to them. The Gulf sturgeon populations dominated by widely spaced

dominate year-classes seem typical for both the Suwannee and Yellow rivers (Sulak and

Clugston 1999).

The Yellow River Gulf sturgeon population seems to be a dynamic population

impacted by years of successful and unsuccessful recruitment, translating into strong and

28

weak year classes. These year classes are the driving force behind the length/age

structure of the population and may change drastically from year to year. Size and age

structure of the population may change as strong year classes move through the

population and are replaced by weaker year classes. Years of high numbers of large fish

dominating the population may be followed by years when the population is dominated

by smaller subadult and adult fish.

Management Implications

The Yellow River is critical habitat for Gulf sturgeon (Federal Register 2003).

That is, the Yellow River is a geographic area that is essential for the conservation of a

threatened species that may require special management consideration or protection. The

Yellow River Gulf sturgeon population appears to be a fairly large, viable population.

Poor management decisions regarding the Yellow River Gulf sturgeon, or the critical

habitat for the species, may have long-term detrimental effects on the population in the

Yellow River and on the entire Gulf of Mexico population. Sufficient spawning habitat

and access to this habitat are the most important aspects of sturgeon life history and in the

continued survival of the species. In the nearby Escambia River, Gulf sturgeon spawning

occurs only at rkms 161 and 170 in Alabama. Similarly, allcases of age-0 fish collection

in the Yellow River have been in Alabama (Craft et al. 2001; Philip Kilpatrich, Alabama

Game and Fish, personal communication) except for one fish collected by USGS. Two

young-of-the-year fish have been collected above the proposed dam site for the Yellow

River, and the third just downstream. Large fish have been tracked far upriver near the

border using sonic and radio tags, and fish have been collected inside Conecuh National

Forest (USGS unpublished data). Impeding the passage of Gulf sturgeon to upriver

29

spawning locations, through dams and other man-made structures would have long-term

detrimental effects, and would likely greatly reduce or eliminate the population.

Gulf sturgeon are modern fish descended from an ancient lineage, with fossil

records dating back 200 million years. Based on current population estimates, it seems

the Yellow River supports the second largest population of Gulf sturgeon. Protection and

preservation of this natural resource for future generations should be a high priority for

public, state, and federal officials.

Future Research

Throughout the three years of research I conducted on the Yellow River, I observed

patterns of habitat use as well as other aspects of sturgeon behavior that may be worthy of

future study. Gulf sturgeon in the Yellow River do not follow the same “holding”

strategies which are common in other river systems. Typically during the summer, Gulf

sturgeon in other river systems are found in “holding areas” usually characterized as a

deep river area and a shallow sandy section (Wooley and Crateau 1985; Foster and

Clugston 1997; Sulak and Clugston 1999; Sulak and Randall 2002). Sturgeon were

captured in deep areas of the Yellow River, described as holding areas (e.g., Sturgeon

Lake) by Craft et al. 2001 during the spring. Sturgeon Lake is an oxbow in the Yellow

River virtually cutoff from the main stem. The deeper Sturgeon Lake (5-9 m)

experiences little current as compared to the rapid, shallow (1-2 m) main channel.

However, after the spring migration upriver was complete, fish were no longer captured

in these deep areas. Sturgeon were captured in shallow water straight-aways during all

sampling seasons. During the three-year study, 44 fish were captured in Sturgeon Lake

(Figure 2) and other deep holes, whereas 104 fish were captured in shallow straight-

aways. The fish captured in Sturgeon Lake were captured up until June 14th, afterwhich

30

no fish were ever captured in Sturgeon Lake. Fish may be using Sturgeon Lake as a

staging area to rest, out of swift currents, before continuing their upriver migration to the

spawning areas. Fishing in the shallow straight-aways was successful during all

sampling periods until the sturgeon emigrated to the bay in the fall.

The possibility of tagging response is another aspect of sturgeon behavior that may

be worthy of future consideration, especially when dealing with population estimates.

There may be a positive bias in my estimates related to a tagging response in the fish

which caused fish to leave the tagging area after being captured and tagged. The

increased number of fish never recaptured after first release suggests permanent

emigration. Telemetry studies could be implemented to determine if a tagging response

occurs, and to what degree. If Gulf sturgeon display a tagging response, it would be

important to quantify the response when estimating population size and survival.

In the Blackwater River, we observed a juvenile sturgeon hooked on a trot-line set

for catfish. This may be a considerable source of juvenile mortality (Figure 12).

Although juvenile mortality was not examined in this study, small increases in juvenile

Gulf sturgeon mortality rates can have negative impacts on the viability of the population

and should be examined in greater detail (Tate and Allen 2002).

31

Table 1. Reported total annual mortality rates for sturgeon species. Species Location Percent Total

Annual Mortality

Explanation Source

Acipenser brevirostrum

Saint John River New Brunswick

11.3-13.9 Dadswell 1979

Acipenser fulvescens

Lake Winnebago, Wisconsin

16.7 17.3

Males Females

Bruch 1999

Moose River, Ontario

12.1 Ages 8-28 Threader and Brousseau 1986

Saint-Laurent River

22.9 Lamoureux and LaForce 1991

Aciepenser oxyrinchus desotoi

Suwannee River, Florida

46 Huff 1975

Pearl River, Mississippi

33.6 Morrow et al. 1998

Suwannee River, Florida

16 Ages 2-25 Sulak and Clugston 1999

Suwannee River, Florida

16-17 Pine et al. 2001

Acipenser oxyrinchus oxyrinchus

Hudson River, New York

16 4

Females Males

Stevenson 1997

Acipenser transmontanus

Sacramento-San Joaquin Estuary, California

13.9 Miller 1972a

Lower Columbia River

46 Ages 12-17 Devore et al. 1995

Sacramento- San Joaquin Estuary, California

12-16 Kohlhorst 1980

Columbia River, Oregon-Washington

24 18

Two different populations

Beamesderfer et al. 1995

32

Table 2. A summary table for the Yellow River, Florida, Gulf sturgeon population estimate including capture probability and number of fish captured.

Sampling Occasion

Number of First Captures

Number of Recaptures

Capture Probability

Population Estimate

Confidence Interval

Summer 2001 101 N/A N/A N/A N/A

Fall 2001 82 16 0.173 566 378-943 Summer 2002 48 23 0.142 500 319-816

Fall 2002 29 11 0.053 754 408-1428

Summer 2003 75 26 0.120 841 487-1507

Fall 2003 59 29 0.102 911 550-1550

33

Table 3. An age-length key created for the Yellow River age and catch data. The numbers in the table correspond to the number of fish at a given age for each size group.

Age in Years FL(cm) 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 88.1-91.9 92-95.9 4 96-99.9 100-103.9 3 2 104-107.9 1 2 108-111.9 3 112-115.9 2 116-119.9 5 1 2 120-123.9 2 2 2 124-127.9 3 1 128-131.9 1 3 3 2 1 132-135.9 3 2 1 2 136-139.9 4 3 2 140-143.9 1 3 1 2 144-147.9 2 1 148-151.9 2 2 1 4 4 152-155.9 156-159.9 1 1 3 2 160-163.9 3 5 1 164-167.9 4 2 4 168-171.9 4 4 2 5 4 172-175.9 2 2 3 176-179.9 5 180-183.9 5 184-187.9 4 4

34

Table 4. A table of all Gulf sturgeon that were captured in the Yellow or Blackwater rivers, Florida, that were initially tagged in a different river. This does not include fish located in other rivers via sonic tags. In Tagging Agency, the following organizations are noted: Northwest Florida Aquatic Preserves (NWFAP), United States Geological Survey (USGS), United States Fish and Wildlife Service (USFWS), and University of Southern Mississippi (USM).

Fish Number Recapture River Recapture Date Pit Tag Number Tagging Agency River Tagged

Date Tagged

10,022 Blackwater 7/10/2002 4229011E5E USGS Yellow 6/12/2001 10,024 Blackwater 5/31/2002 422616447D USGS Yellow 6/12/2001 10,028 Yellow 6/12/2001 4179327266 USM Pascagoula 6/14/2000 10,044 Blackwater 7/10/2002 417928165A USGS Yellow 6/14/2000 10,051 Blackwater 5/29/2003 41794D401D USGS Yellow 6/19/2001 10,064 Blackwater 7/10/2002 422067637B USGS Yellow 7/25/2001 10,069 Yellow 7/26/2001 4179506F76 NWFAP Escambia 9/14/2000 10,077 Blackwater 6/19/2002 522067637B USGS Yellow 7/26/2001 10,133 Yellow 10/9/2001 42354B1D68 Unknown Unknown Unknown 10,150 Blackwater 8/2/2002 423558254C USGS Yellow 10/15/2001 10,184 Blackwater 6/19/2002 423A64213 USGS Yellow 10/23/2001 10,193 Yellow 5/6/2002 000-328-628 Unknown Unknown Unknown 10,231 Yellow 9/30/2002 422E1D2F78 Unknown Unknown Unknown 10,256 Yellow 6/18/2002 420A783F47 USFWS Choctawhatchee 10/30/1999 10,257 Yellow 5/29/2002 4204083037 USFWS Choctawhatchee 10/23/1999 10,259 Yellow 10/16/2002 4238062155 Unknown Unknown Unknown 10,260 Yellow 10/16/2002 422F4C727D USFWS Choctawhatchee 10/15/2000 10,274 Yellow 5/30/2003 4203786A17 USFWS Choctawhatchee 10/25/1999 10,330 Yellow 6/19/2002 42304E5C12 USFWS Choctawhatchee 11/8/2001 10,332 Yellow 7/10/2002 422F35137D USFWS Choctawhatchee 11/11/2000 10,334 Yellow 7/10/2002 422E145240 Unknown Unknown Unknown 10,336 Yellow 7/10/2002 420B10024F Unknown Unknown Unknown 10,337 Yellow 7/10/2002 7F7D377924 Unknown Unknown Unknown 10,341 Yellow 6/19/2002 7F7E6B3F5E USFWS Escambia 6/29/1995 10,343 Yellow 7/21/2003 423050085F USFWS Choctawhatchee 10/18/2001

35

Table 4. Continued. Fish Number Recapture River Recapture Date Pit Tag Number Tagging Agency River

Tagged Date Tagged

10,355 Yellow 7/22/2003 420B215C00 USFWS Choctawhatchee 10/25/1999 10,356 Yellow 7/22/2003 422F2B7E28 USFWS Escambia 6/19/2002 10,361 Yellow 7/22/2003 42304A1D44 USFWS Choctawhatchee 10/22/2000 10,373 Yellow 7/31/2003 42286F2D1A USFWS Escambia 6/12/2002 10,392 Yellow 8/21/2003 422F4F0878 USFWS Escambia 6/20/2002

36

Figure 1. A map of the northern Gulf of Mexico with rivers inhabited by Gulf sturgeon

highlighted.

37

Figure 2. A map and aerial photographs representing the Yellow River and Blackwater

River, Florida, including the major sampling sites.

38

Figure 3. Photograph of the two tag types used during this study. A T-bar tag is shown

on top with a PIT tag underneath.

39

Figure 4. An age bias plot of pairwise age comparisons between two agers for 92 fish.

The errors bars represent the 95% confidence interval about the mean age assigned by ager 2 for all fish at a given age, aged by ager 1. The 1:1 reference line is also plotted for comparison.

40

0

0.5

1

1.5

2

2.5

3

3.5

0 5 10 15 20 25

Age in Years

ln N

umbe

r of

Fis

h

.

Figure 5. Catch curve for Yellow River Gulf sturgeon based on number-at-age data

collected during the summer and fall of 2001. Ages with no fish were not included in the catch curve.

41

Figure 6. The top chart is a length frequency histogram for Gulf sturgeon captured in

the Yellow River, Florida, during 2001-2002, and the bottom is a percent frequency histogram of Gulf sturgeon captured in the Suwannee River, Florida during 2001-2002.

N=247

0

2

46

8

10

12

85 95 105

115

125

135

145

155

165

175

185

195

>205

Fork Length (cm)

Perc

ent F

requ

ency

N=395

0

2

4

6

8

10

12

14

85 95 105

115

125

135

145

155

165

175

185

195

>205

Fork Length (cm)

Perc

ent F

requ

ency

9

42

Figure 7. Von Bertalanffy growth model fit to observed length-at-age data for Yellow

River, Florida, Gulf sturgeon, fall and summer 2001, and a von Bertalanffy growth model fit to observed length-at-age data for Suwannee River, Florida Gulf sturgeon.

Figure 8. Photograph of a 26.1-cm FL Gulf sturgeon captured in the Yellow River,

Florida, approximately 3.5 km upriver of the Highway 90 bridge.

43

N=175

0

5

10

15

20

25

85 95 105

115

125

135

145

155

165

175

185

195

More

Fork Length (cm)

Num

ber

of F

ish

Figure 9. A length frequency histogram for Yellow River, Florida, Gulf sturgeon

captured during 2001.

N=72

0123456789

10

85 95 105

115

125

135

145

155

165

175

185

195

More

Fork Length (cm)

Num

ber

of F

ish

Figure 10. A length frequency histogram for Yellow River, Florida, Gulf sturgeon

captured during 2002.

44

N=129

0

2

4

6

8

10

12

14

16

85 95 105

115

125

135

145

155

165

175

185

195

More

Fork Length (cm)

Num

ber

of F

ish

Figure 11. A length frequency histogram for Yellow River, Florida, Gulf sturgeon

captured during 2003.

Figure 12. A 61.8 cm TL Gulf sturgeon captured on a fisherman’s catfish trot-line in

Coopers Basin on the Blackwater River, found and released by my research team.

APPENDIX CATCH DATA FOR THE YELLOW AND BLACKWATER RIVERS (2001-2003)

46

Table A-1. Catch data for the yellow and blackwater rivers (2001-2003) Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,001 0 10/14/2002 Yellow V 9503 9504 420B2C1470 1482 1316 17750 10,002 0 6/9/2001 Yellow V G1082 G1083 4179454169 1426 1256 18000 10,003 0 6/9/2001 Yellow V G1085 G1084 4179466A48 1604 1412 30500 9 10,003 1 6/27/2003 Yellow R G1085 G1084 4179466A48 1650 1450 30750 10,004 0 6/9/2001 Yellow V G1087 G1086 4179123959 1450 1266 18000 7 10,005 0 6/9/2001 Yellow V G1089 G1088 4179541738 1788 1570 40000 10 10,006 0 6/9/2001 Yellow V G1091 G1092 422637085B 1921 1736 50000 10 10,006 1 8/21/2002 Yellow R G1091 G1092 422637085B 1919 1732 40000 10,006 2 7/31/2003 Yellow R G1091 G1082 422637085B 1962 1772 50500 10,007 0 6/9/2001 Yellow V G1093 G1094 4179291A12 1000 888 5500 10,007 1 10/7/2001 Yellow R G1093 G1094 4179291A12 1002 898 5500 10,007 2 5/6/2002 Yellow R G1093 G1094 4179291A12 1098 976 9000 10,007 3 10/10/2002 Yellow R G1093 G1094 4179291A12 1096 974 7000 10,008 0 6/9/2001 Yellow V G1096 G1095 41790E0913 1424 1240 18300 6 10,008 1 10/11/2001 Yellow R G1096 G1095 41790E0913 1450 1264 18500 10,009 0 6/9/2001 Yellow V G1098 G1097 4179475F18 1540 1374 21250 8 10,009 1 7/26/2001 Yellow R G1098 G1097 4179475F18 1538 1370 19500 10,010 0 6/10/2001 Yellow V G1076 G1077 41793A6158 1818 1622 45000 10 10,011 0 6/10/2001 Yellow V G1079 G1078 4179335E2D 1874 1650 47000 10 10,012 0 6/10/2001 Yellow V G1080 G1081 41791D5828 1264 1090 11750 10,012 1 10/12/2003 Yellow R G2963 G1081 41791D5828 1520 1310 22500 10,013 0 6/11/2001 Yellow V G1002 G1001 422G0F2111 1478 1340 23250 10,013 1 10/5/2001 Yellow R G1002 G1001 42260F2111 1486 1335 22250 10,014 0 6/11/2001 Yellow V G1004 G1005 4226185056 1970 1760 53000 10,015 0 6/11/2001 Yellow V G1022 G1023 42261F6058 1546 1378 26250 10,016 0 6/11/2001 Yellow V G1024 G1025 4228722B17 1812 1636 47500 10 10,017 0 6/11/2001 Yellow V G1452 G1451 41792F6621 1640 1482 27750 16

47

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,017 1 7/22/2003 Yellow R G1452 G1451 41792F6621 1638 1472 24250 10,018 0 6/11/2001 Yellow V G1454 G1453 4226381C17 1232 1040 11000 10,018 1 10/6/2001 Yellow R G1454 G1453 4226381C17 1232 1102 10750 10,019 0 6/11/2001 Yellow V G1455 G1456 41791B7D79 1162 1034 11000 3 10,019 1 7/26/2001 Yellow R G1455 G1456 41791B7D79 1160 1103 7600 10,019 2 6/18/2002 Yellow R G1455 G1456 41791B7D79 1274 1126 13000 10,019 3 10/12/2003 Yellow R G1455 G1456 41791B7D79 1490 1331 17800 10,020 0 6/11/2001 Yellow V G1457 G1458 4179086821 2052 1840 62200 18 10,020 1 7/31/2003 Yellow R G1457 G1458 4179086821 2050 1837 60900 10,021 0 6/12/2001 Yellow V 8595 G1461 7F7D353B7B 1788 1590 41000 8 10,022 0 6/12/2001 Yellow V G1007 G1006 4229011E5E 1758 1540 39000 10,022 1 7/10/2002 Blackwater R G1007 G1379 4229011E5E 1831 1600 32500 10,022 2 8/2/2002 Blackwater R G1007 G1379 4229011E5E 1830 1610 41500 10,023 0 6/12/2001 Yellow V G1008 G1009 42257A1C02 1430 1250 17000 10,023 1 7/27/2001 Yellow R G1008 G1009 42257A1C02 1414 1250 15000 10,024 0 6/12/2001 Yellow V G1010 G1011 422616447D 1630 1450 30000 8 10,024 1 5/31/2002 Blackwater R G1010 G1011 422616447D 1700 1510 32500 10,025 0 6/12/2001 Yellow V G1012 G1013 42261D6A32 1670 1480 30500 12 10,026 0 6/12/2001 Yellow V G1014 G1015 42287E4067 1780 1580 41000 9 10,027 0 6/12/2001 Yellow V G1016 G1017 4226116064 910 810 4100 10,027 1 10/17/2001 Yellow R G1016 G1017 42376F7E69 938 832 4500 3 10,027 2 10/10/2003 Yellow R G1016 G1017 42376F7E69 1172 1032 9000 10,028 0 6/12/2001 Yellow V G1460 G1459 4179327266 1820 1644 41250 9 10,029 0 6/12/2001 Yellow V G1462 G1463 4179345614 1888 1690 51500 14 10,029 1 8/21/2002 Yellow R G1462 G1825 4179345616 1880 1676 47500 10,030 0 6/12/2001 Yellow V G1465 G1464 4179424950 1016 892 5750 10,030 1 10/8/2001 Yellow R G1465 G1464 4179424950 1032 907 5750

48

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,031 0 6/12/2001 Yellow V G1466 G1467 41794F407A 1514 1362 21250 7 10,032 0 6/12/2001 Yellow V G1468 G1469 41792F0910 1616 1447 28250 10,033 0 6/12/2001 Yellow V G1470 G1471 4179541873 2024 1844 56500 14 10,034 0 6/13/2001 Yellow V G1019 G1018 42286D3652 1160 1080 9800 10,035 0 6/13/2001 Yellow V G1177 G1178 4179243721 1906 1714 49000 12 10,036 0 6/13/2001 Yellow V G1179 G1180 4179535E5B 1768 1596 43500 9 10,037 0 6/13/2001 Yellow V G1252 G1251 4229073349 1096 952 7600 10,038 0 6/13/2001 Yellow V G1253 G1254 42286E5241 1880 1680 46000 10 10,038 1 7/22/2003 Yellow R G1253 G1254 4313120D60 1924 1722 45000 10,039 0 6/13/2001 Yellow V G1255 G1256 4226034F58 1820 1680 45000 10 10,039 1 6/18/2002 Yellow R G1255 G1256 4226034F58 1834 1622 43500 10,039 2 5/28/2003 Yellow R G2877 G1256 4226034F58 1848 1632 46000 10,039 3 7/31/2003 Yellow R G2827 G1256 4226034F58 1842 1636 40900 10,040 0 6/13/2001 Yellow V G1474 G1473 4179067B74 1226 1074 10500 10,040 1 10/17/2001 Yellow R G1474 G1473 4179067B74 1248 1092 11000 10,040 2 10/22/2002 Yellow R G1474 G1473 4179067B74 1290 1130 11000 10,041 0 6/13/2001 Yellow V G1475 G1176 4179443757 1349 1188 14000 10,041 1 10/6/2001 Yellow R G1475 G1176 4179443757 1360 1200 13250 10,042 0 6/14/2001 Yellow V G1181 9542 42034F5F57 1966 1828 59750 12 10,043 0 6/14/2001 Yellow V G1182 G1183 4179113455 1458 1286 17500 10,044 0 6/14/2001 Yellow V G1184 G1185 417928165A 2000 1778 51000 11 10,044 1 7/10/2002 Blackwater R G1184 G1185 417928165A 2006 1780 55000 10,045 0 6/14/2001 Yellow V G1186 G1187 41792B3709 1568 1390 27500 10,046 0 6/14/2001 Yellow V G1188 G1189 4179410506 1476 1318 18750 10,047 0 6/14/2001 Yellow V G1190 G1191 41792F5246 1782 1606 41000 10,048 0 6/14/2001 Yellow V G1257 G1258 422571315A 1560 1360 24000 10,048 1 10/16/2001 Yellow R G1257 G1258 422571315A 1568 1372 24250

49

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,049 0 6/14/2001 Yellow V G1259 G1260 417923202D 1410 1290 21000 8 10,049 1 7/25/2001 Yellow R G1259 G1260 417923202D 1404 1293 20250 10,049 2 10/9/2003 Yellow R G1260 G1261 4232676F5B 1335 1190 13500 10,050 0 6/14/2001 Yellow V G1262 G1261 42256C4753 1420 1250 18000 10,051 0 6/19/2001 Yellow V G1028 G1029 41794D401D 1498 1308 19958 6 10,051 1 10/6/2001 Yellow R G1028 G1029 41794D401D 1482 1306 19500 10,051 2 5/3/2002 Yellow R G1028 G1029 41794D401D 1568 1380 25500 10,051 3 5/29/2003 Blackwater R G1028 G1029 41794D401D 1620 1428 30000 10,051 4 6/26/2003 Blackwater R G1028 G1029 41794D401D 1600 1480 27000 10,052 0 6/19/2001 Yellow V G1031 G1030 4179526757 1505 1346 18938 11 10,053 0 6/19/2001 Yellow V G1033 G1032 41793BDE7D 1359 1181 12701 5 10,054 0 6/19/2001 Yellow V G1035 G1034 4179440F6C 1397 1257 16551 6 10,054 1 10/8/2003 Yellow R G2673 G2674 4179440F6C 1222 1386 15500 10,055 0 7/24/2001 Yellow V 9533 G1482 41792D063C 1791 1592 44750 10,055 1 6/18/2002 Yellow R G1828 G1482 41792D063C 1802 1600 41000 10,056 0 7/24/2001 Yellow V G1244 G1245 42287D1409 1040 920 11000 4 10,057 0 7/24/2001 Yellow V G1248 N/A 4226304635 1085 1040 16500 4 10,058 0 7/24/2001 Yellow V G1250 G1249 4225676E11 955 835 7500 2 10,058 1 10/27/2001 Yellow R G1250 G1249 4225676E11 996 870 4000 10,059 0 7/24/2001 Yellow V G1477 G1476 41790A370A 1270 1200 12000 4 10,060 0 7/24/2001 Yellow V G1478 G1479 41794A4062 1319 1064 13000 5 10,061 0 7/24/2001 Yellow V G1481 G1480 4179623E4E 1857 1684 46000 10,062 0 7/24/2001 Yellow V G1483 G1484 41791F0F45 1368 1200 15000 7 10,063 0 7/24/2001 Yellow V G1485 G1486 41790A5544 1878 1702 51500 10,063 1 5/3/2002 Yellow R G1485 G1486 41790A5544 1892 1702 57000 10,064 0 7/25/2001 Yellow V G1238 G1239 422067637B 1774 1568 34500 7 10,064 1 7/10/2002 Blackwater R G1238 G1239 422067637B 1812 1600 37000

50

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,064 2 8/2/2002 Blackwater R G1238 G1239 423A4E380F 1806 1590 35400 10,065 0 7/25/2001 Yellow V G1240 G1241 42256D0A41 1510 1330 21000 6 10,066 0 7/25/2001 Yellow V G1242 G1243 41791D1A65 1558 1352 24250 7 10,067 0 7/25/2001 Yellow V G1487 G1488 41790A4120 1350 1218 15250 7 10,067 1 8/21/2003 Yellow R G1750 G1550 41790A4120 1355 1220 14500 10,067 2 10/3/2003 Yellow R G1550 G1750 41790A4120 1336 1230 15200 10,068 0 7/25/2001 Yellow V G1490 G1489 4179287C52 1759 1648 38000 9 10,069 0 7/26/2001 Yellow V 10055 10056 4179506F76 1800 1588 33500 10,070 0 7/26/2001 Yellow V G1152 G1153 41792A2A1C 1886 1678 41000 10,070 1 10/18/2001 Yellow R G1152 G1153 41792A2A1C 1884 1672 40000 10,071 0 7/26/2001 Yellow V G1155 G1154 417916727D 1490 1310 21000 10,072 0 7/26/2001 Yellow V G1156 G1157 4179194D63 2058 1827 51000 10,073 0 7/26/2001 Yellow V G1158 G1159 4179207A2B 1574 1394 25600 10,073 1 6/25/2003 Yellow R G1158 G1159 4179207A2B 1650 1464 30000 10,074 0 7/26/2001 Yellow V G1230 G1231 4179214E58 1810 1622 41200 10,075 0 7/26/2001 Yellow V G1232 G1233 4229122B05 1102 960 5750 3 10,076 0 7/26/2001 Yellow V G1234 G1235 4179293F28 1530 1342 22750 6 10,076 1 10/6/2001 Yellow R G1234 G1051 4179293F28 1538 1350 24500 10,077 0 7/26/2001 Yellow V G1236 G1237 41790E0D09 1198 1050 8000 3 10,077 1 10/13/2001 Yellow R G1236 G1790 41790E0D09 1212 1060 9500 10,077 2 6/19/2002 Blackwater R G1236 G1239 522067637B 1812 1600 37500 10,078 0 7/26/2001 Yellow V G1491 G1493 4179565431 1668 1464 29000 7 10,079 0 7/26/2001 Yellow V G1495 G1494 41792B024D 1123 1000 8500 3 10,079 1 6/27/2003 Yellow R G1495 G1494 41792B024D 1370 1216 16800 10,080 0 7/26/2001 Yellow V G1497 G1496 417918196A 968 865 5500 3 10,081 0 7/26/2001 Yellow V G1499 G1498 41792D7222 1326 1182 13000 4 10,081 1 8/20/2002 Yellow R G1499 G1498 41792D7222 1449 1292 16000

51

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,082 0 7/26/2001 Yellow V G1500 G1151 41790E1705 1510 1310 18750 7 10,083 0 7/27/2001 Yellow V G1160 G1161 4179560E44 2010 1800 52750 10,083 1 10/11/2003 Yellow R G1160 G1161 4179560E44 2014 1860 50500 10,084 0 7/27/2001 Yellow V G1163 G1162 41793B190E 1132 1032 8750 4 10,085 0 7/27/2001 Yellow V G1165 G1164 4226306B49 1541 1358 22500 8 10,086 0 7/27/2001 Yellow V G1166 G1167 41791D5640 1492 1316 18750 6 10,086 1 4/18/2003 Yellow R G2886 G2885 41791D5640 1510 1340 22750 10,086 2 10/12/2003 Yellow R G2886 G2885 41791D5640 1514 1340 18000 10,087 0 7/27/2001 Yellow V G1168 G1169 41793F3250 1778 1580 36750 10,088 0 7/27/2001 Yellow V G1226 G1227 4179401261 1511 1340 18500 10,089 0 7/27/2001 Yellow V G1229 G1228 4226376067 1780 1590 40750 10,089 1 10/7/2001 Yellow R G1229 G1275 4226376067 1496 1770 41000 10,090 0 9/10/2001 Yellow V G1171 G1170 7F7D381668 1480 1308 12000 11 10,090 1 6/18/2002 Yellow R G1171 G1170 7F7D381668 1310 1488 16000 10,091 0 9/10/2001 Yellow V G1172 G1173 7F7D41520F 1438 1296 17000 5 10,091 1 8/20/2002 Yellow R G1172 G1173 4232077715 1520 1368 22500 10,092 0 9/10/2001 Yellow V G1174 G1175 42304D0614 1880 1680 45000 10,093 0 9/10/2001 Yellow V G1770 G1771 7F7D364D7B 1450 1300 18000 7 10,094 0 9/10/2001 Yellow V G1772 G1773 7F7D264B7B 1295 1130 11000 4 10,095 0 9/10/2001 Yellow V G1775 G1774 7F7D365B06 1585 1405 21000 9 10,096 0 9/12/2001 Yellow V G1759 G1758 7F7D37181A 1258 1110 9000 5 10,097 0 9/12/2001 Yellow V G1760 G1761 7F7D354245 1900 1710 46000 11 10,098 0 9/12/2001 Yellow V G1763 G1762 41793D170D 1912 1680 42750 9 10,099 0 9/12/2001 Yellow V G1765 G1764 4179481B53 1320 1164 11000 4 10,099 1 10/9/2002 Yellow R G1765 G1764 4179481B53 1402 1230 15000 10,100 0 9/12/2001 Yellow V G1766 G1767 42261F0938 1410 1220 13500 6 10,100 1 5/4/2002 Yellow R G1767 G1766 42261F0938 1454 1270 19000

52

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,100 2 8/21/2002 Yellow R G1766 G1767 42261F0938 1482 1296 16750 10,101 0 9/12/2001 Yellow V G1769 G1768 417921461E 1680 1500 24000 7 10,101 1 5/4/2002 Yellow R G1769 G1768 417921461E 1750 1560 30500 10,101 2 10/17/2002 Yellow R G1769 G1768 417921461E 1726 1536 27500 10,101 3 10/7/2003 Yellow R G1769 G1768 417921461E 1792 1600 31000 10,102 0 10/4/2001 Yellow V G1072 G1073 7F7D35307B 1272 1178 11500 10,102 1 5/8/2002 Yellow R G1072 G1073 7F7D35307B 1286 1148 11500 10,102 2 8/21/2002 Yellow R G1072 G1073 7F7D35307B 1276 1142 11250 10,103 0 10/4/2001 Yellow V G1075 G1074 5221121414 1532 1364 21500 10,104 0 10/5/2001 Yellow V G1055 G1056 420B402614 1814 1632 40500 10,104 1 6/18/2002 Yellow R G1055 G1056 420B402614 1840 1652 52500 10,105 0 10/5/2001 Yellow V G1057 G1058 4233697C6A 2002 1828 53250 10,106 0 10/5/2001 Yellow V G1060 G1059 4235435423 1480 1309 19500 10,107 0 10/5/2001 Yellow V G1061 G1062 4433631E14 1476 1318 20000 10,108 0 10/5/2001 Yellow V G1067 G1063 423372715D 1864 1662 40000 10,108 1 4/18/2003 Yellow R G1067 G1063 423372715D 1912 1706 54000 10,109 0 10/5/2001 Yellow V G1069 G1068 42327D392E 1324 1155 13000 4 10,110 0 10/5/2001 Yellow V G1071 G1070 42353B7C2B 1532 1386 23000 10,111 0 10/6/2001 Yellow V G1052 9846 42033F0538 1917 1746 41250 10,112 0 10/6/2001 Yellow V G1053 G1054 423321553A 1515 1334 19500 10,113 0 10/6/2001 Yellow V G1264 G1263 4233076D7D 1596 1408 24500 10,114 0 10/6/2001 Yellow V G1266 G1265 42332D7756 1542 1366 20250 10,115 0 10/6/2001 Yellow V G1268 G1267 4232201A78 1602 1404 22750 10,115 1 10/5/2003 Yellow R G1268 G1267 4232201A78 1602 1410 23000 10,116 0 10/6/2001 Yellow V G1270 G1269 42355D6719 1542 1354 20000 10,117 0 10/6/2001 Yellow V G1271 G1272 4234003A47 1832 1630 45250 10,118 0 10/6/2001 Yellow V G1273 G1274 42336F3333 1660 1490 28500 12

53

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,119 0 10/7/2001 Yellow V G1291 G1291 423366647A 958 846 4750 10,120 0 10/7/2001 Yellow V G1293 G1294 42332A5D58 1510 1348 19500 10,121 0 10/7/2001 Yellow V G1296 G1295 42354F6D60 1672 1482 28000 10,121 1 5/28/2003 Yellow R G1296 G1768 417921461E 1790 1590 35000 10,122 0 10/7/2001 Yellow V G1297 G1298 4233294C76 1774 1584 36500 10,122 1 5/3/2002 Yellow R G1297 G1298 4233294C76 1806 1614 37000 9 10,122 2 7/22/2003 Yellow R G1297 G1298 4233294C76 1802 1610 39250 10,123 0 10/7/2001 Yellow V G1300 G1299 423321191F 1400 1298 18000 10,123 1 6/18/2002 Yellow R G1300 G1299 423321191F 1318 1480 21000 10,124 0 10/8/2001 Yellow V G1281 G1280 4232676F5B 1141 1021 8000 10,124 1 6/18/2002 Yellow R G1281 G1280 4232676F58 1100 1210 11000 10,125 0 10/8/2001 Yellow V G1284 G1282 423321407D 1980 1850 42750 10,126 0 10/8/2001 Yellow V G1288 G1287 42340A0078 1656 1477 24750 10,126 1 8/20/2002 Yellow R G1288 G1287 42340A0078 1654 1476 24000 10,126 2 8/21/2003 Yellow R G1288 G1287 42340A0078 1662 1480 24500 10,127 0 10/8/2001 Yellow V G1290 G1289 4238032640 1444 1302 19250 10,128 0 10/9/2001 Yellow V G10070 G1756 421C042507 1942 1720 46000 10,128 1 4/9/2003 Yellow R G2896 G2897 421C042507 1978 1758 64000 10,129 0 10/9/2001 Yellow V G1194 G1193 4233186A34 1716 1554 31250 10,130 0 10/9/2001 Yellow V G1276 G1277 4235460105 812 725 3500 10,130 1 10/7/2003 Yellow R G1276 G1277 4235460105 1042 932 6500 10,131 0 10/9/2001 Yellow V G1278 G1757 42332E1266 1758 1570 36500 10,132 0 10/9/2001 Yellow V G1753 G1752 42327B7443 1018 895 5900 10,133 0 10/9/2001 Yellow V G1755 G1754 42354B1D68 1574 1409 25750 10,134 0 10/10/2001 Yellow V G1196 G1195 4233314A63 1920 1696 45000 10,135 0 10/10/2001 Yellow V G1198 G1197 42321C410E 1896 1704 53500 10,136 0 10/10/2001 Yellow V G1199 G1200 42332F466F 1355 1176 13750

54

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,136 1 7/31/2003 Yellow R G1509 G1200 42332F466F 1392 1210 14000 10,137 0 10/10/2001 Yellow V G1776 G1777 42321E6D36 1904 1706 45000 10,138 0 10/10/2001 Yellow V G1779 G1778 423559547F 1900 1686 44500 10,138 1 9/20/2002 Yellow R G1779 G1570 ------ 1914 1705 41250 10,139 0 10/11/2001 Yellow V G1780 G1781 42353D701C 1236 1010 10500 4 10,140 0 10/11/2001 Yellow V G1783 G1782 4237786642 798 698 3250 10,141 0 10/11/2001 Yellow V G1785 G1784 423409231F 1428 1268 17500 10,141 1 10/4/2003 Yellow R G1785 G1784 423409231F 1490 1312 19000 10,142 0 10/11/2001 Yellow V G1786 G1787 4232746621 1452 1286 17000 7 10,142 1 7/31/2003 Yellow R G1786 G1787 4232746621 1478 1310 16500 10,143 0 10/12/2001 Yellow V G1788 G1789 4232303065 1811 1605 40500 11 10,144 0 10/14/2001 Yellow V G1792 G1791 42326F1354 1882 1680 44000 10,145 0 10/14/2001 Yellow V G1793 G1794 42335F617B 1644 1449 27500 10,146 0 10/14/2001 Yellow V G1795 G1796 4233142147 1582 1414 24500 14 10,147 0 10/15/2001 Yellow V G1797 G1798 4235642342 1618 1438 28000 10,148 0 10/15/2001 Yellow V G1800 G1799 42331A6102 1772 1580 37000 10,149 0 10/15/2001 Yellow V G1963 G1964 4232084D32 1534 1404 21500 11 10,150 0 10/15/2001 Yellow V G1966 G1967 423558254C 1888 1704 44250 9 10,150 1 8/21/2003 Yellow R G1966 G1967 423558254C 1920 1726 46500 10,150 1 8/2/2002 Blackwater R . G1967 423558254C 1880 1710 47500 10,151 0 10/15/2001 Yellow V G1969 G1968 423331037F 1884 1660 45000 10,151 1 10/18/2002 Yellow R G1969 G1968 423331037F 1905 1685 44500 10,151 2 8/21/2003 Yellow R G1969 G1741 423331037F 1918 1695 46660 10,152 0 10/15/2001 Yellow V G1970 G1971 4232740F3E 1608 1420 21000 6 10,153 0 10/15/2001 Yellow V G1973 G1972 4233200010 1544 1362 23000 7 10,154 0 10/15/2001 Yellow V G1975 G1974 4234072A46 1440 1296 19000 10,154 1 8/20/2002 Yellow R G1975 G1974 4234072A46 1440 1294 18000

55

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,155 0 10/16/2001 Yellow V G1953 G1952 42330F002F 1481 1322 19250 10,156 0 10/16/2001 Yellow V G1955 G1954 42337E6178 1322 1150 13500 4 10,157 0 10/16/2001 Yellow V G1957 G1956 42355F5414 1540 1362 18500 9 10,158 0 10/16/2001 Yellow V G1958 G1959 42325E4E43 1168 1022 9500 3 10,159 0 10/16/2001 Yellow V G1961 G1960 4233220F3C 1790 1610 39500 10,160 0 10/16/2001 Yellow V G1977 G1951 4234062D5F 1942 1722 53000 11 10,160 1 5/6/2002 Yellow R G1977 G1951 4234062D5F 1978 1766 70750 10,160 2 8/21/2003 Yellow R G1977 G1951 4234062D5F 2006 1782 55500 10,161 0 10/16/2001 Yellow V G1978 G1979 4233323371 1351 1198 16000 6 10,161 1 10/3/2003 Yellow R G1532 G1531 4233323371 1370 1268 16500 10,162 0 10/16/2001 Yellow V G1980 G1981 4233264002 1748 1620 35500 10,162 1 5/30/2002 Yellow R G1980 G1981 4233264002 1762 1630 38000 10,163 0 10/16/2001 Yellow V G1984 G1982 4233206E02 1834 1631 40250 10,164 0 10/16/2001 Yellow V G1985 G1986 42326E086F 1356 1264 17250 10,165 0 10/17/2002 Yellow R 8439 G2000 4233143400 1426 1270 16000 10,165 0 10/17/2001 Yellow V 8439 G2000 4233143400 1436 1274 17500 10,166 0 10/17/2001 Yellow V G1874 G1875 4232071B33 920 805 4500 3 10,167 0 10/17/2001 Yellow V G1988 G1987 4232111E0D 1716 1518 35500 10,168 0 10/17/2001 Yellow V G1989 G1990 4235556C1F 1150 1000 7750 10,169 0 10/17/2001 Yellow V G1992 G1993 4235447920 1052 928 6750 10,170 0 10/17/2001 Yellow V G1994 G1995 423050B01 1366 1220 14000 10,171 0 10/17/2001 Yellow V G1996 G1997 4233301315 1480 1314 18500 10,172 0 10/17/2001 Yellow V G1998 G1999 42355F3E1C 1501 1334 21500 10,173 0 10/18/2001 Yellow V G1870 G1871 4232621969 868 774 4200 10,174 0 10/18/2001 Yellow V G1873 G1872 423275747F 1026 1010 4250 10,175 0 10/19/2001 Yellow V G1865 G1866 42354D3E17 1528 1354 19000 10,176 0 10/20/2001 Yellow V G1864 G1863 4232716851 1272 1120 11500

56

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,176 1 8/21/2002 Yellow R G1864 G1863 4232716851 1276 1124 12000 10,177 0 10/21/2001 Yellow V G1862 G1861 4202750B65 2000 1790 58500 10,178 0 10/23/2001 Yellow V G1860 G1859 4232184867 1378 1200 16600 10,179 0 10/24/2001 Yellow V G1855 G1858 42355C024E 1486 1317 20250 8 10,180 0 10/25/2001 Yellow V G1853 G1854 4235621043 1090 950 7000 4 10,180 1 10/12/2003 Yellow R G2997 G1854 4235621043 1244 1006 11500 10,181 0 10/27/2001 Yellow V G1851 G1852 4232670644 1505 1330 20000 10,182 0 10/29/2001 Yellow V G1897 G1898 4233134255 1662 1498 29000 10,183 0 10/29/2001 Yellow V G1899 G1900 42376E125B 2244 2046 71500 10,184 0 5/2/2002 Yellow V G1877 G1876 423A642133 1802 1598 41250 10,184 1 6/19/2002 Blackwater R G1877 G1876 423A642133 1802 1694 39500 10,185 0 5/3/2002 Yellow V G1101 G1102 421E551219 1912 1797 55000 10,186 0 5/3/2002 Yellow V G1879 G1878 423A764061 2010 1810 72000 10,187 0 5/3/2002 Yellow V G1880 G1881 42352A2F43 1550 1374 23500 10,188 0 5/3/2002 Yellow V G1882 G1883 422E15755A 1536 1376 26000 10,189 0 5/4/2002 Yellow V G1884 G1885 42380E3F14 1308 1160 10,190 0 5/4/2002 Yellow V G1886 G1887 423B6B3A50 1172 1044 10750 10,191 0 5/4/2002 Yellow V G1889 G1888 000-373-832 1608 1440 27750 10,192 0 5/4/2002 Yellow V G1890 G1891 423A6C2273 1759 1570 49500 10,193 0 5/6/2002 Yellow V G1892 G1893 000-328-628 1820 1636 41500 9 10,194 0 5/6/2002 Yellow V G1895 G1894 423364670A 1790 1604 48250 10,195 0 5/6/2002 Yellow V G1947 G1948 423317390C 1910 1722 66000 20 10,196 0 5/6/2002 Yellow V G1950 G1949 423B70252D 1672 1494 40250 11 10,196 1 4/9/2003 Yellow R G2898 G1949 423B70252D 1682 1502 42000 10,197 0 5/8/2002 Yellow V G1936 G1935 4238093337 1470 1302 19000 10,198 0 5/8/2002 Yellow V G1937 G1939 4235162A5A 1766 1578 48000 10,198 1 6/20/2002 Yellow R G1937 G1939 4235162A5A 1764 1578 46000

57

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,199 0 5/8/2002 Yellow V G1940 G1941 421F01404F 1842 1648 47500 17 10,200 0 5/8/2002 Yellow V G1942 G1944 4235360B6D 1278 1200 11750 4 10,200 1 10/23/2002 Yellow R G1942 G1944 4235360B6D 1264 1110 11000 10,200 2 10/12/2003 Yellow R G1942 G1944 4235360B6D 1400 1238 16000 10,201 0 5/8/2002 Yellow V G1945 G1946 4234462807 1260 1003 14500 7 10,201 1 10/9/2003 Yellow R G1946 G1945 4234462807 1342 1166 17000 10,202 0 5/29/2002 Yellow V 9842 9840 42037E431A 1878 1692 43250 10,202 1 6/18/2002 Yellow R 9840 9842 42037E431A 1874 1689 41500 10,203 0 5/29/2002 Yellow V G1201 G1204 000-792-776 1952 1754 60000 10,204 0 5/29/2002 Yellow V G1208 G1209 4238105E1D 1836 1610 38500 10,205 0 5/30/2002 Yellow V G1210 G1211 422E046251 1624 1438 34000 10,205 1 7/9/2002 Yellow R G1210 G1211 422E046251 1628 1441 31750 10,205 2 10/17/2002 Yellow R G1210 G1211 422E046251 1615 1430 30750 10,206 0 6/18/2002 Yellow V G1220 G1221 422E024C51 1806 1608 42000 10,206 1 10/17/2002 Yellow R G1220 G2689 422E024C51 1840 1660 38500 10,207 0 6/18/2002 Yellow V G1363 G1362 423A6B5731 1895 1700 47500 10,208 0 6/18/2002 Yellow V G1364 G1365 42351C2A6A 1896 1660 53000 10,208 1 8/21/2003 Yellow R G1364 G1365 42351C2A6A 1895 1662 47250 10,209 0 6/18/2002 Yellow V G1367 G1366 42343B425A 1872 1668 47000 10,210 0 6/18/2002 Yellow V G1369 G1368 421E7A6A64 1500 1340 21000 10,210 1 8/21/2002 Yellow R G1369 G1368 421E7A6A64 1524 1351 20500 10,210 2 6/25/2003 Yellow R G1369 G1368 421E7A6A64 1528 1356 23500 10,211 0 6/18/2002 Yellow V G1372 G1373 4233033B58 2022 1786 55000 10,211 1 8/20/2002 Yellow R G1372 G1373 4233033B58 2026 1786 51500 10,212 0 6/18/2002 Yellow V G1375 G1374 4234523671 1502 1358 20500 10,212 1 10/12/2003 Yellow R G1375 G1374 422E240626 1530 1380 20000 10,213 0 6/20/2002 Yellow V G1827 G1826 4179554331 1672 1476 30500

58

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,213 1 8/21/2003 Yellow R G1827 G1826 4179554331 1728 1532 32000 10,214 0 7/9/2002 Yellow V G1848 G1846 422E170F4B 1464 1292 20500 10,215 0 7/9/2002 Yellow V G1849 G1850 4179411B10 1562 1415 24250 10,216 0 7/25/2002 Yellow V G1385 G1386 4235366D39 1840 1650 42250 10,216 1 10/12/2002 Yellow R G2684 G1386 4235366D39 1820 1630 41000 10,217 0 8/20/2002 Yellow V G1802 G1801 423B5F6A20 1452 1288 17000 10,217 1 10/13/2003 Yellow R G1802 G1801 423B5F6A20 1460 1296 16000 10,218 0 8/20/2002 Yellow V G1803 G1804 4235230F03 1882 1700 42250 10,219 0 8/20/2002 Yellow V G1805 G1806 42336E4117 1427 1294 19000 10,220 0 8/20/2002 Yellow V G1807 G1808 422E1A4115 1832 1648 41500 10,221 0 8/20/2002 Yellow V G1809 G1810 422E194748 1550 1358 21500 10,222 0 8/20/2002 Yellow V G1812 G1811 42326B1742 1612 1430 27000 10,222 1 10/5/2003 Yellow R G1812 G1811 42326B1742 1635 1452 26500 10,223 0 8/20/2002 Yellow V G1814 G1813 423A6B3A34 1740 1528 34000 10,224 0 8/21/2002 Yellow V G1815 G1816 42351F7476 1412 1269 15250 10,225 0 8/21/2002 Yellow V G1818 G1817 4232726H16 1076 944 6000 10,225 1 10/7/2003 Yellow R G1916 G1817 422E18202B 2050 1840 74000 10,226 0 8/21/2002 Yellow V G1819 G1820 4235424F18 1382 1230 14000 10,227 0 8/21/2002 Yellow V G1822 G1821 4233132401 898 782 4000 10,228 0 8/21/2002 Yellow V G1824 G1823 4235470874 1052 922 6250 10,229 0 9/15/2002 Yellow V G1571 G1572 422E241C2A 878 774 3750 10,230 0 9/15/2002 Yellow V G1575 G1573 423A4B0C70 1544 1376 21000 10,231 0 9/30/2002 Yellow V G1568 G1569 422E1D2F78 1394 1248 14000 10,232 0 10/8/2002 Yellow V G1566 G1567 423A510070 1910 1719 40150 10,233 0 10/9/2002 Yellow V G1558 G1559 ----- 1930 1711 42000 10,233 1 10/24/2002 Yellow R G1559 G1558 423A573D19 1936 1720 43000 10,234 0 10/9/2002 Yellow V G1562 G1563 422E00490 1071 940 1250

59

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,235 0 10/9/2002 Yellow V G1829 G1830 42352B513B 1142 1010 7100 10,235 1 10/12/2002 Yellow R G1829 G1830 42352B513B 1142 1010 7000 10,236 0 10/9/2002 Yellow V G2676 G2677 4232794926 1510 1338 19500 10,237 0 10/10/2002 Yellow V G2678 G2679 423A531B38 1524 1342 19500 10,237 1 10/21/2002 Yellow R G2678 G2679 423A531B38 1620 1360 19000 10,238 0 10/10/2002 Yellow V G2681 G2680 423224736B 888 870 3500 10,238 1 10/4/2003 Yellow R G2681 G2681 423224736B 1500 960 6100 10,239 0 10/10/2002 Yellow V G2682 G2683 42332C2571 960 810 3750 10,240 0 10/12/2002 Yellow V G2686 G2685 422E06207B 1386 1238 15000 10,240 1 10/12/2003 Yellow R G2686 G2685 422E06207B 1382 1224 16500 10,241 0 10/17/2002 Yellow V G2691 G2690 422E105462 1552 1396 24000 10,242 0 10/17/2002 Yellow V G2692 G2693 4238153639 1440 1274 17500 10,242 1 10/11/2003 Yellow R G2692 G2693 4238153639 1460 1329 19500 10,243 0 10/17/2002 Yellow V G2695 G2694 4235112B06 1380 1256 17000 10,244 0 10/17/2002 Yellow V G2697 G2696 423B700639 1840 1642 40250 10,244 1 7/22/2003 Yellow R G2697 G2698 423B700639 1852 1666 51500 10,245 0 10/17/2002 Yellow V G2699 G2698 42354411213 1508 1360 20250 10,246 0 10/17/2002 Yellow V G2700 G2950 4237710F1E 1562 1744 39000 10,247 0 10/18/2002 Yellow V G2346 G2347 4235355048 1460 1312 20000 10,248 0 10/18/2002 Yellow V G2948 G2949 423B085A2F 1910 1714 43000 10,248 1 5/28/2003 Yellow R G2948 G1588 423B085A2F 1940 1739 52000 10,249 0 10/19/2002 Yellow V G2943 G2942 422E130F47 1060 932 5500 10,250 0 10/19/2002 Yellow V G2944 G2945 423A627D03 962 847 5000 10,250 1 10/13/2003 Yellow R G2344 G2845 423A627D03 1136 1000 9000 10,251 0 10/20/2002 Yellow V G2941 G2940 42330B051A 1032 926 6000 10,252 0 10/23/2002 Yellow V G2937 G2936 4235156438 1220 1064 9000 10,253 0 10/23/2002 Yellow V G2939 G2938 4238083323 1620 1412 24000

60

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,254 0 10/24/2002 Yellow V G2935 G2934 42380A0339 1852 1646 40000 10,255 0 6/9/2001 Yellow V G1100 8492 41791D7259 1682 1490 33500 8 10,255 1 10/9/2001 Yellow R G1100 8492 41791D7259 1680 1490 31000 10,256 0 6/18/2002 Yellow V 8370 8369 420A783F47 1638 1470 29500 10,257 0 5/29/2002 Yellow V G1205 G1206 4204083037 1611 1432 28250 10,258 0 6/18/2002 Yellow V G1370 G1371 000-620-100 2110 1910 74000 10,259 0 10/16/2002 Yellow V G1392 G1391 4238062155 1990 1770 50250 10,260 0 10/16/2002 Yellow V G2688 G2687 422F4C727D 1668 1486 28000 10,261 0 3/17/2003 Yellow V G2899 G2900 42353A6F56 1480 1380 24000 10,262 0 4/9/2003 Yellow V G2894 G2895 423777003E 1338 1260 20500 10,263 0 4/11/2003 Yellow V G2893 G2892 4233243A13 1764 1560 40000 10,264 0 4/18/2003 Yellow V G2890 G2889 42376D0824 1988 1770 57000 10,264 1 6/25/2003 Yellow R G2890 G2889 42376D0824 2000 1786 43900 10,265 0 4/18/2003 Yellow V G2887 G2888 4234235605 1608 1424 29500 10,266 0 4/29/2003 Yellow V G2881 G2880 420270367F - - 45750 10,267 0 5/28/2003 Yellow V G2878 G2879 423B124368 1000 876 7250 10,268 0 5/28/2003 Yellow V G2876 G1576 4233770256 1824 1640 43500 10,269 0 5/28/2003 Yellow V G1578 G1577 423271714A 1906 1742 61000 10,270 0 5/28/2003 Yellow V G1580 G1579 423A691335 1446 1320 21500 10,271 0 5/28/2003 Yellow V G1582 G1581 4234092B59 1424 1276 19500 10,272 0 5/28/2003 Yellow V G1583 G1584 42343F0716 1092 965 9500 10,273 0 5/28/2003 Yellow V G1585 G1586 422E216767 1668 1494 34750 10,274 0 5/30/2003 Yellow V 3960 G2856 4203786A17 1998 1881 59000 10,275 0 5/30/2003 Yellow V G2857 G2858 42380D0C0D 1330 1192 17500 10,276 0 5/30/2003 Yellow V G2859 G2860 422D795D21 1294 1140 14000 10,277 0 5/30/2003 Yellow V G2861 G2862 4235362F74 1465 1365 24000 10,277 1 6/25/2003 Yellow R G2861 G2862 4235362F74 1452 1356 21500

61

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,278 0 5/30/2003 Yellow V G2863 G2864 423A5F3D4E 1881 1720 57250 10,279 0 5/30/2003 Yellow V G2865 G2866 423A585034 1328 1180 18250 10,280 0 6/25/2003 Yellow V G2867 G2868 4235186477 1832 1650 49000 10,281 0 6/25/2003 Yellow V G2869 G2870 423275601B 1610 1430 24500 10,282 0 6/25/2003 Yellow V G2872 G2871 41794D1F51 1974 1782 58000 10,283 0 4/18/2003 Yellow V G2882 G2883 423A6D3948 1424 1265 20500 10,284 0 5/31/2002 Blackwater V G1213 G1212 423A583E26 1806 1628 43500 10,285 0 5/31/2002 Blackwater V G1215 G1214 7F7D322522 1676 1488 30500 10,286 0 5/31/2002 Blackwater V G1216 G1217 423B5D6035 1938 1734 50000 10,287 0 5/31/2002 Blackwater V G1219 G1218 423A693E49 2022 1826 69500 10,288 0 6/19/2002 Blackwater V G1351 G1222 423320190B 1362 1186 16500 10,289 0 6/19/2002 Blackwater V G1353 G1352 423A545B3E 1634 1444 26000 10,290 0 6/19/2002 Blackwater V G1355 G1354 7F7D35232A 2120 1930 72000 10,291 0 6/19/2002 Blackwater V G1357 G1356 423513692C 1760 1608 42500 10,291 1 7/10/2002 Blackwater R G1357 G1356 423513692C 1760 1606 41250 10,292 0 6/19/2002 Blackwater V G1359 G1358 4235106E52 1820 1634 49500 10,293 0 6/19/2002 Blackwater V G1360 G1361 422E222B31 1610 1794 42750 10,293 1 7/10/2002 Blackwater R G1360 G1361 422E222B31 1784 1600 42000 10,294 0 7/10/2002 Blackwater V G1378 G1377 423534672C 1731 1534 35500 10,295 0 7/10/2002 Blackwater V G1381 G1380 4235453E40 1800 1651 47250 10,296 0 7/10/2002 Blackwater V G1384 G1383 4234042047 1944 1756 54750 10,297 0 8/2/2002 Blackwater V G1388 G1387 422D0E3D 1510 1350 22000 10,298 0 8/2/2002 Blackwater V G1390 G1389 42351C6F2A 1740 1560 34000 10,299 0 8/2/2002 Blackwater V G1392 G1391 4238062155 1970 1755 53000 10,300 0 8/2/2002 Blackwater V G1394 G1393 4235386654 1790 1590 39500 10,301 0 7/10/2002 Blackwater V G1832 G1376 42377A1A7D 1691 1476 33000 10,302 0 7/10/2002 Blackwater V G1834 G1833 7F7D403E42 1876 1682 54500

62

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,303 0 7/10/2002 Blackwater V G1840 G1839 4235254E32 1655 1476 30500 10,304 0 7/10/2002 Blackwater V G1842 G1843 7F7D36426C 1716 1542 36250 10,305 0 7/10/2002 Blackwater V G1844 G1845 42351F6408 1610 1439 27500 10,306 0 6/19/2002 Blackwater V G1903 G1904 42380A6759 1724 1540 36000 10,307 0 6/19/2002 Blackwater V G1907 G1906 4235303727 1532 1344 24000 10,308 0 6/19/2002 Blackwater V G1909 G1908 42354B6013 2070 1890 63000 10,309 0 6/19/2002 Blackwater V G1910 G1911/G1912 522104331D 1614 1420 30500 10,310 0 6/19/2002 Blackwater V G1914 G1913 41793E2A7C 1818 1614 41500 10,311 0 6/19/2002 Blackwater V G1915 G1223 5220607F26 1796 1582 42500 10,312 0 6/19/2002 Blackwater V G1916 G1917 422E18202B 2052 1840 65250 10,312 1 6/26/2003 Blackwater R G1916 G1917 422E18202B 2064 1850 65000 10,313 0 6/19/2002 Blackwater V G1918 G1224 42352A5238 1806 1624 41500 10,314 0 6/19/2002 Blackwater V G1920 G1919 42380F1452 1694 1490 32250 10,315 0 6/19/2002 Blackwater V G1922 G1921 4237711E43 1732 1580 38000 10,316 0 6/19/2002 Blackwater V G1924 G1923 4179540451 1612 1422 29000 10,317 0 5/29/2003 Blackwater V G1590 G1587 4233044468 1769 1559 37000 10,318 0 5/29/2003 Blackwater V G1591 G1592 423B202637 1868 1672 45500 10,319 0 5/29/2003 Blackwater V G1593 G1594 4235371D29 1604 1410 25000 10,320 0 5/29/2003 Blackwater V G1595 G1596 42320B320E 1802 1622 42000 10,321 0 5/29/2003 Blackwater V G1598 G1597 42326A5B73 1956 1750 61000 10,322 0 5/29/2003 Blackwater V G1600 G1599 42353C177F 1746 1529 36250 10,323 0 5/29/2003 Blackwater V G2855 G2852 4235255729 1706 1529 37500 10,324 0 6/26/2003 Blackwater V G2873 G2874 4179387375 1875 1652 45500 10,325 0 6/26/2003 Blackwater V G1703 G1701 423B336E17 2000 1794 54500 10,326 0 6/26/2003 Blackwater V G1705 G1704 422D7F692D 1466 1325 18000 10,327 0 6/26/2003 Blackwater V G1706 G1707 42327A2A38 1780 1565 43000 10,328 0 6/26/2003 Blackwater V G1708 G1709 423B65497F 1785 1590 40500

63

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,329 0 6/26/2003 Blackwater V G1710 G1711 4235233873 1910 1695 57000 10,330 0 6/19/2002 Blackwater R/V 05764 05763 42304E5C12 1928 1736 53000 10,331 0 6/26/2003 Blackwater V G1714 G1713 423B726D75 1580 1392 25900 10,332 0 7/10/2002 Blackwater R/V 08587 G1838 422F35137D 1582 1402 26000 10,333 0 6/19/2002 Blackwater R/V 10147 G1905 4226205704 1550 1474 30500 10,334 0 7/10/2002 Blackwater R/V A1161 A1162 422E145240 1600 1448 29000 10,335 0 7/10/2002 Blackwater R/V G1382 9838 420B3E4903 1523 1334 22500 10,335 1 8/21/2003 Yellow R/V G1832 9838 420B3E4903 1619 1421 24500 10,336 0 7/10/2002 Blackwater R/V G1837 G1835 420B10024F 1776 1586 43750 10,337 0 7/10/2002 Blackwater R/V G1841 8636 7F7D377924 1952 1774 54000 10,338 0 6/27/2003 Yellow V G1715 G1716 423B3F451E 1820 1635 41500 10,339 0 6/27/2003 Yellow V G1717 G1718 4237793C23 1488 1315 18500 10,340 0 6/27/2003 Yellow V 9238 8486 4233030C28 1981 1794 52000 10,341 0 7/19/2003 Yellow V G1719 G1720 435F7E5C66 n/a 1280 10,342 0 7/21/2003 Yellow V G1721 G1722 43103D427E 1950 1788 50250 10,343 0 7/21/2003 Yellow V G1724 G1725 423050085F 1876 1670 46100 10,344 0 7/21/2003 Yellow V G1676 G1677 42355E522E 1638 1446 25100 10,345 0 7/21/2003 Yellow V G1679 G1678 42377B5D1D 1902 1740 55000 10,346 0 7/21/2003 Yellow V G1681 G1680 43132B4A26 1826 1640 41000 10,347 0 7/21/2003 Yellow V G1682 G1683 4235423263 1430 1278 17900 10,348 0 7/22/2003 Yellow V G1685 G1684 4311051E6D 1836 1646 42500 10,349 0 7/22/2003 Yellow V G1686 G1687 430E722838 1800 1616 34500 10,350 0 7/22/2003 Yellow V G1688 G1689 431072515E 1944 1738 51100 10,351 0 7/22/2003 Yellow V G1690 G1692 4310466460 1964 1732 48750 10,351 1 8/21/2003 Yellow R G1690 G1692 431046646D 1960 1732 48500 10,352 0 7/22/2003 Yellow V G1695 G1693 42354C1A1A 1946 1740 48900 10,353 0 7/22/2003 Yellow V G1697 G1696 423797203D 1683 1542 28000

64

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,354 0 7/22/2003 Yellow V G1698 G1699 430E762F39 1874 1742 43250 10,355 0 7/22/2003 Yellow V 3648 G1700 420B215C00 - - 54250 10,356 0 7/22/2003 Yellow V G1675 G1674 422F2B7E28 2046 1858 63000 10,357 0 7/22/2003 Yellow V G1672 G1673 430E6ADE2E 1370 1220 15000 10,358 0 7/22/2003 Yellow V G1670 G1671 422E0C2746 1896 1688 40500 10,359 0 7/22/2003 Yellow V G1668 G1669 42380B4277 1738 1540 33000 10,359 1 10/11/2003 Yellow R G1668 G2980 42380B4277 1756 1557 32500 10,360 0 7/22/2003 Yellow V G1667 G1666 4315453502 1710 1510 32250 10,361 0 7/22/2003 Yellow V G1665 G1664 42304A1D44 1766 1578 38500 10,362 0 7/22/2003 Yellow V G1662 G1663 4310435854 1788 1582 38000 10,363 0 7/22/2003 Yellow V G1661 G1660 4313103231 1820 1624 43250 10,363 1 10/2/2003 Yellow R G1661 G1660 4313103231 1800 1664 41000 10,364 0 7/22/2003 Blackwater V G1658 G1659 423A67122A 1986 1818 46500 10,365 0 7/22/2003 Blackwater V G1656 G1657 42351D512B 1738 1554 34500 10,366 0 7/22/2003 Blackwater R G1655 G1654 42261F6D58 1574 1406 24500 10,367 0 7/30/2003 Blackwater V G1652 G1653 423B6D380F 1676 1530 29500 10,368 0 7/30/2003 Blackwater V G1651 G1501 42286D2002 1742 1512 30000 10,369 0 7/31/2003 Yellow V G1503 G1502 430E67284C 1835 1666 42200 10,370 0 7/31/2003 Yellow V G1504 G1505 42355F3832 1482 1310 18750 10,370 1 10/10/2003 Yellow R G1504 G1505 42355F3832 1480 1310 20000 10,371 0 7/31/2003 Yellow V G1506 G1507 4235260816 1742 1548 35500 10,371 1 10/11/2003 Yellow R G1506 G1507 4235260816 1816 1618 36000 10,372 0 7/31/2003 Yellow V G1510 G1511 43132D4201 1480 1310 21500 10,373 0 7/31/2003 Yellow R/V G1513 G1512 42286F2D1A - 1412 22200 10,374 0 7/31/2003 Yellow V G1514 G1515 43132A742D 1504 1332 21000 10,374 1 10/12/2003 Yellow R G1514 G1515 43132A742D 1540 1362 22000 10,375 0 7/31/2003 Yellow V G1517 G1516 43131A7662 - 1804 54000

65

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,376 0 7/31/2003 Yellow V G1518 G1519 43103F0E3C 1754 1560 34000 10,377 0 7/31/2003 Yellow V G1521 G1520 423B47063D 1585 1408 23500 10,378 0 7/31/2003 Yellow R/V G1522 8436 423802207A 1654 1472 24500 10,379 0 7/31/2003 Yellow V G1523 G1524 423B5E587D 1999 1880 68750 10,380 0 7/31/2003 Yellow V G1726 G1525 4232637B33 1576 1390 23900 10,381 0 7/31/2003 Yellow V G1728 G1727 423A6C1420 1847 1618 38000 10,382 0 8/21/2003 Yellow V G1729 G1730 431307006B 2010 1810 56250 10,383 0 8/21/2003 Yellow V G1731 G1732 43130C2929 1876 1648 37000 10,384 0 8/21/2003 Yellow V G1733 G1734 4315674A3D 1834 1632 40000 10,385 0 8/21/2003 Yellow V G1736 G1735 4310595D31 1786 1575 40000 10,386 0 8/21/2003 Yellow V G1738 G1737 4312723BF3B 1795 1590 33333 10,387 0 8/21/2003 Yellow V G1740 G1739 436010547A 1608 1430 24000 10,388 0 8/21/2003 Yellow V G1743 G1742 4310436D10 2062 1848 52500 10,389 0 8/21/2003 Yellow V G1744 G1745 43106249DA 1955 1745 44500 10,390 0 8/21/2003 Yellow V G1747 G1746 43153A400D 1746 1535 31500 10,391 0 8/21/2003 Yellow V G1549 G1548 43112E2E23 1945 1710 44000 10,392 0 8/21/2003 Yellow R/V G1546 G1547 422F4F0878 1698 1522 31000 10,393 0 8/21/2003 Yellow V G1544 G1545 4233161838 1792 1600 38750 10,394 0 10/10/2003 Yellow V G2807 G2806 42337A2868 1554 1380 19500 10,394 0 6/19/2002 Blackwater R/V G1902 G1901 7F7E6B3F5E 1800 1590 43000 10,395 0 10/10/2003 Yellow V G2805 G2804 423332455B 1350 1290 14250 10,396 0 10/10/2003 Yellow V G2803 G2802 423364D78 1424 1259 17000 10,397 0 10/10/2003 Yellow R/V 9240 G2801 42331C1359 1993 1766 54500 10,398 0 10/10/2003 Yellow V G2976 G2977 4232677557 1160 990 7000 10,399 0 10/11/2003 Yellow R/V G2978 G2979 42286F564F 1550 1378 21000 10,400 0 10/11/2003 Yellow V G2982 G2981 423310352F 1941 1718 49000 10,401 0 10/11/2003 Yellow V G2984 G2983 4238140464 950 934 5000

66

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,402 0 10/11/2003 Yellow V G2986 G2985 42337F6358 1452 1276 19000 10,403 0 10/11/2003 Yellow V G2988 G2987 42321A1041 1449 1286 18500 10,404 0 10/11/2003 Yellow V G2990 G2989 4232710768 1774 1580 37100 10,405 0 10/11/2003 Yellow V G2991 G2992 42327B3945 1026 910 6000 10,406 0 10/11/2003 Yellow V G2993 G2994 4238025F35 1362 1239 15800 10,407 0 10/11/2003 Yellow V G2954 G2952 423409796A 1647 1502 29500 10,408 0 10/11/2003 Yellow V G2956 G2955 42355C2540 - - 45000 10,409 0 10/11/2003 Yellow V G2958 G2957 423775672E 1170 1046 10000 10,410 0 10/12/2003 Yellow V G2960 G2959 42327D3A39 1590 1420 24000 10,411 0 10/12/2003 Yellow V G2962 G2967 42355C6E68 1480 1332 20000 10,412 0 10/12/2003 Yellow V G2964 G2965 423369561B 1729 1530 34000 10,413 0 10/12/2003 Yellow V G2968 G2967 42355C4C5F 1592 1420 24250 10,414 0 10/12/2003 Yellow V G2970 G2969 4234056727 1658 1420 27600 10,415 0 10/12/2003 Yellow V G2995 G2996 423452551C 1429 1272 17500 10,416 0 10/12/2003 Yellow V G2999 G2998 4233036C52 1502 1370 21000 10,417 0 10/12/2003 Yellow V G3000 G2971 4233323145 1674 1470 28000 10,418 0 10/12/2003 Yellow V G2828 G2827 42353A6524 1852 1704 46000 10,419 0 10/12/2003 Yellow R/V G2829 G2830 4233706253 1785 1594 37000 10,420 0 10/12/2003 Yellow V G2831 G2832 4233134E09 1550 1385 22500 10,421 0 10/12/2003 Yellow V G2833 G2834 42327B5D25 1034 920 6800 10,422 0 10/12/2003 Yellow R/V G2972 G2973 42303D7D5B 1948 1732 44000 10,423 0 10/13/2003 Yellow R/V G2974 G2975 422F3F6D21 1716 1612 43000 10,424 0 10/13/2003 Yellow V G2836 G2835 42355F1659 1922 1750 49000 10,425 0 10/13/2003 Yellow V G2838 G2837 4234082979 1742 1588 38500 10,426 0 10/13/2003 Yellow V G2840 G2839 42331F0B12 980 866 5750 10,427 0 10/13/2003 Yellow R/V 06942 06943 42354B4856 1296 1140 12000 10,428 0 10/13/2003 Yellow V G2842 G2841 4233793334 1000 880 5750

67

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,429 0 10/13/2003 Yellow V G2844 G2843 4235491915 1525 1326 21500 10,430 0 10/2/2003 Yellow V G1643 G1642 422E115761 990 880 5000 10,431 0 10/2/2003 Yellow V G1541 G1540 42380F380D 2000 1796 56500 10,432 0 10/2/2003 Yellow R/V G1539 9230 7F7D37492A 1810 1616 35000 10,433 0 10/2/2003 Yellow V G1538 G1537 42331F266E 1100 978 7500 10,434 0 10/3/2003 Yellow V G1536 G1535 42327C4B06 1278 1126 10200 10,435 0 10/3/2003 Yellow V G2653 G2652 4233647B28 1474 1336 1800 10,436 0 10/3/2003 Yellow V G1533 G1534 42330B393B 1260 1009 11000 10,437 0 10/4/2003 Yellow V G2655 G2654 423770257B 1520 1390 21500 10,438 0 10/4/2003 Yellow V G2657 G2656 42322E4A43 1784 1610 45000 10,439 0 10/4/2003 Yellow V G1529 G1530 43131B2752 1846 1650 44000 10,440 0 10/4/2003 Yellow V G2659 G2658 423406134A 1534 1366 22000 10,441 0 10/4/2003 Yellow V G2660 G2661 42336A4038 1520 1444 24000 10,442 0 10/5/2003 Yellow V G2663 G2662 4233081339 1880 1701 40000 10,443 0 10/5/2003 Yellow V G2664 G2665 43103F0A26 1620 1420 22500 10,444 0 10/5/2003 Yellow V G2666 G2667 423A585A46 1618 1460 27000 10,445 0 10/6/2003 Yellow V G1528 G1527 4233641845 1638 1466 26000 10,446 0 10/6/2003 Yellow V G1526 G2668 42321B3F1D 1845 1662 43500 10,447 0 10/6/2003 Yellow V G2670 G2669 4233742E7A 838 730 2000 10,448 0 10/6/2003 Yellow V G2672 G2671 423379593C 1588 1412 23500 10,449 0 10/7/2003 Yellow V G2824 G2825 423320740E 1382 1204 16000 10,450 0 10/7/2003 Yellow V G2822 G2823 43127E244F 1558 1430 24500 10,451 0 10/7/2003 Yellow V G2821 G2820 4235585A03 1356 1220 14750 10,452 0 10/7/2003 Yellow V G2819 G1818 4238007D65 1026 912 5250 10,453 0 10/7/2003 Yellow V G2817 G2816 4233102B39 1482 1314 19500 10,454 0 10/7/2003 Yellow V G2815 G2814 42332C5F07 900 800 5000 10,455 0 10/9/2003 Yellow V G2812 G2813 4232673A65 1980 1788 58000

68

Table A-1. Continued. Number Obs Capture Date River Status T-bar Left T-bar Right Pit Tag TL(mm) FL(mm) Wt(gm) Age 10,456 0 10/9/2003 Yellow V G2810 G2811 4233033704 1444 1310 19250 10,457 0 10/10/2003 Yellow V G2809 G2808 430E471826 1292 1162 8500

69

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BIOGRAPHICAL SKETCH

Jim Berg was born on December 21, 1978, in Philadelphia, Pennsylvania, the son

of William and Donna Berg. He was raised in Reeders, a small town in the Pocono

Mountains of Pennsylvania. His love of the aquatic environment and particularly the

ocean stems from growing up on a small lake in the Poconos and yearly trips to the

Atlantic coast with his family. After high school, he entered Long Island University-

Southampton College in the fall of 1996, and graduated in May of 2000 with a B.S. in

marine biology. After graduation, he moved to Gainesville, Florida, to work with the

United States Geological Survey. In the fall of 2001, he began his graduate work in the

Department of Fisheries and Aquatic Sciences at the University of Florida. He will

graduate with a Master of Science degree in May 2004. He plans on moving back to the

Northeast to pursue a career as a research biologist working with marine or anadramous

fisheries.