Evaluation of Lake Sturgeon Habitat in the Genesee River”

Final Report

Assessment of Habitat Use by Experimentally Stocked Juvenile Lake Sturgeon

Submitted to:

United States Environmental Protection Agency - Great Lakes National Program Office

Submitted by U.S. Geological Survey, Tunison Laboratory of Aquatic Science 3075 Gracie Rd. Cortland NY 13045-9357

Partially Funded by United States Environmental Protection Agency Great Lakes National Program Office

Interagency Agreement Numbers DW-14-947993-01-0 & DW-14-947991-01-0 “Evaluation of Lake Sturgeon Habitat in the Genesee River”

Co-Principal Investigator Dr. Dawn E. Dittman USGS Tunison Lab. of Aquatic Science Co-Principal Investigator Emily C. Zollweg USFWS Lower Great Lakes FRO

EXECUTIVE SUMMARY

Lake sturgeon (Acipenser fulvescens) is a native fish species that is a species of concern across the Great Lakes Region. Historically abundant in Lake Ontario, this large, primitive, macroinvertivore has virtually disappeared due to over fishing and habitat degradation. Management and restoration of any threatened species requires careful reassessment of the habitats in which the species was once common. The Genesee River is one of the major tributaries to Lake Ontario. Historically, the lower portion of the river had a substantial sturgeon presence, but it was extirpated before the 1930’s. River health has improved to the point that there was a window of opportunity to explore lake sturgeon restoration possibilities. One management tool used in threatened species conservation is the experimental stocking of hatchery-reared fish into areas where the original populations have been extirpated for an applied evaluation of the current available habitat suitability. In September 2003, 900 fingerling lake sturgeon were planted at Genesee river kilometer (rkm) 9.1. One hundred and sixty seven juvenile sturgeon were captured or recaptured during the first year of habitat use assessment. The most successful capture site was the first deep area downstream of the release site, (rkm 8.2), just downstream of the State Route 104 Bridge. This site averages over 6 m depth and has gravelly-shelly substrate. The second most successful capture site (rkm 6.2) was a deeper area (9 to 10 m) with gravelly-rocky substrate and substantial woody debris. In October 2004, the Schnabel population estimate was 366 individuals (95 % CI 248 to 563) present in the river more than one year after introduction. These 2003 year class (03YC) sturgeon had an average length of 210 mm and an average weight of 44 g when released. In October of 2004, 57 captured fish averaged 374 mm and 195 g. In September of 2004, an additional 1,000 fingerlings were released. These 2004 year class (04YC) fish averaged 169 mm and 23 g when released. During the 2005 field season, the majority of 441 captures were in the deepest parts of each sampled river reach with the most successful sites the same as in 2004. For the most part these sites had gravelly to sandy substrates and were spread throughout the assessment area. Sturgeon presence was not correlated with the water condition factors measured. The Schnabel population estimate as of August of 2005 was 392 individuals still present of the 900 released in the 03YC (95% CI 319 to 481) and 679 individuals still present of the 1,000 released in the 2

04YC (95% CI 498 to 952). As of August of 2005 the average size of the 03YC fish was 437 mm and 340 g (N = 48). The August of 2005 average size of the 04YC fish was 298 mm and 113 g (N = 89). Diet samples taken in June, July, and August (N = 120) consisted of 98.56% Chironomidae with low numbers of other insects and mollusks. These results indicate that the released juvenile sturgeon are successfully using the available Genesee River habitat as nursery habitat in a manner consistent with habitat suitability predictions. Future assessments are needed to confirm long term success of these fish and their continuing use of the Genesee River.

TABLE OF CONTENTS

Executive Summary Page 2

Table of Contents Page 4

List of Tables Page 5

List of Figures Page 6

Introduction Page 7 Lake Sturgeon Biology and Life History Study Area/Genesee River History Project Significance to Rochester RAP and Lake Ontario LaMP Problem Definition: Assessment Genesee Habitat for Lake Sturgeon Page 11 Experimental Stocking as a Habitat Evaluation Tool Pre-stocking Research in the Genesee

Objectives Page 13

Methods Page 14 Experimental Stocking Evaluation of Habitat Use by Stocked Sturgeon

Results Page 20 Sturgeon Mark-Recapture Experiment. Capture Locations and Sturgeon Movement Between Recaptures. Page 21 Habitat Evaluation. Overall and at the Capture Sites. Physical Factors Page 27 Invertebrate Community Sturgeon Diet. Page 38 Sturgeon Growth Patterns Page 39

Discussion Page 44 Success of Juvenile Sturgeon in the Genesee River Habitat Evaluation and Habitat Suitability Implications and next steps.

Acknowledgements Page 46

References Page 46

List of Tables

Table 1. Composition of sediment in spaced transects Page 28

Table 2. Invertebrate composition and #/m2 in spaced transects (1-12). Page 29

Table 3. Invertebrate composition and #/m2 in spaced transects (13-23). Page 30

Table 4. Sediment composition in sturgeon capture locations. Page 31

Table 5. Physical factors by site with catch, November 2004 Page 33

Table 6. Physical Factors by site with catch, May 05 Page 34

Table 7. Physical Factors by site with catch, July 05 Page 35

Table 8. Physical Factors by site with catch, August 05 Page 36

Table 9. Average size the 03YC fish from stocking to October 2004 Page 39

Table 10. Average size the 03YC fish May 2005 to August 2004. Page 40

Table 11. Average size the 04YC fish May 2005 to August 2004. Page 40

List of Figures

Figure 1. Geographic location of the Genesee River. Page 8

Figure 2. Lower Falls of the Genesee River. Page 9

Figure 3. Rochester AOC and potential sturgeon habitat. Page 10

Figure 4. Scute marking sturgeon. Page 15

Figure 5. Stocking site. Page 15

Figure 6. Lake Sturgeon in the net Page 17

Figure 7. Weighting Lake Sturgeon Page 17

Figure 8. Tagging. Page 18

Figure 9. Ponar in action. Page 19

Figure 10. Stomach Flushing. Page 20

Figure 11. Capture locations of 03YC sturgeon. Page 21

Figure 12. Map of the most successful capture sites. Page 22

Figure 13. Below 104 Bridge. Primary sturgeon capture site, #2. Page 23

Figure 14. 30 ft Hole, second most successful capture site, #4. Page 23

Figure 15. Capture locations of 04YC sturgeon. Page 24

Figure 16. 03YC moving downstream, 2003 to 2005. Page 25

Figure 17. 03YC moving upstream, 2003 to 2005. Page 25

Figure 18. 03YC moving upstream in 2005. Page 26

Figure 19. Locations of spaced environmental samples. Page 27

Figure 20. Large fraction of sediment from the 30 ft Hole, rkm 6.3. Page 30

Figure 21. Macroinvertebrates at sturgeon capture sites. Page 32

Figure 22. Overall invertebrate community composition Summer 2005. Page 37

Figure 23. Diversity represented in the juvenile sturgeon diet. Page 38

Figure 24. Size distribution at stocking 03YC. Page 41

Figure 25. Size distribution at stocking 04YC. Page 41

Figure 26. Change in the size distribution of the 03YC sturgeon in 2004. Page 42

Figure 27. Change in the size distribution of 03YC in 2005. Page 42

Figure 28. Change in size distribution of 04YC fish in 2005. Page 43

Figure 29. Example of individual growth of recaptured individuals. Page 43

INTRODUCTION

Sturgeon species, which historically have been an important component of native fish communities and have supported lucrative fisheries, are in serious decline throughout the world (Beamesderfer and Farr 1997, Birstein 1997, Auer 1999, Secor et al. 2002). Loss of large, long- lived species has been observed to be characteristic of stressed ecosystems (Kelso et al. 1996, Busch and Lary 1996, Musick 1999, Gardmark et al. 2003). Lake sturgeon (Acipenser fulvescens) is listed as either locally threatened or endangered across the majority of its range (Auer 1999, Holey et al. 2000, Welsh 2004). Adaptive management practices combined with restoration and enhancement projects for lake sturgeon are being conducted by Canadian and United States agencies throughout the Great Lakes basin (Carlson 2000, Hay-Chmielewski and Wheland 1997, Auer 2003). Lake sturgeon has been identified as a target species for restoration and enhancement of self-sustaining populations in Lake Ontario by the U.S. Fish and Wildlife Service (USFWS) and the New York State Department of Environmental Conservation (NYS DEC, (Carlson 1995, Lowie et al. 2000, Carlson 2000). The stated goal by the NYS DEC is to "reestablish lake sturgeon as a viable, self-sustaining component of the fish community in New York State to the point of it no longer being classified as threatened." (Bouton 1994, Carlson 2000, Carlson 2005). Sound conservation theory recommends that multiple populations of species in danger be maintained (Hess 1996, Young 1999, Pikitch et al. 2005). Lake sturgeon restoration to areas where they were historically abundant is considered essential to overall Great Lakes management goals of restoring native fish communities and improving ecosystem function (Auer 1999, Holey et al. 2000). This study was designed to investigate the practicality of restoration of lake sturgeon to an area in New York where the species was once abundant.

Lake Sturgeon Biology and Life History

Lake sturgeon is a primitive, long-lived, late-maturing, bottom feeding fish species (Harkness and Dymond 1961, Auer 1999, Galarowicz 2003). Lake sturgeon is a river and nearshore warm water species that prefers waters above 10OC and 5 to 10 meters depth (Bemis and Kynard 2002). They engage in extensive migration for feeding and spawning (Auer 1999). Adult lake sturgeon can average 75 to 198 cm in length and grow up to an average of 45 kg. The maximum recorded size was 274 cm and 125 kg. Females mature between 14 and 33 years, males between 7

8 and 12 years. Spawning is in stream rapids in the spring, with each female spawning at 4 to 9 year intervals and males every 2 to 7 years (Harkness and Dymond 1961, Nilo et al. 1996, Threader et al. 1998). The diet of lake sturgeon consists of invertebrates (aquatic insect larvae and mollusks) and some fish (Harkness and Dymond 1961, Kempinger 1996, Jackson et al. 2002). This species is a classic case for an easily threatened species, vulnerable to overfishing, habitat fragmentation, and compromises in spawning and feeding habitat quality and access.

Study Area/Genesee River History

The Genesee River is the one of the major tributaries to Lake Ontario in New York (Figure 1, Clune 1963, Carlson 1995). It drains 6,390 km2, contains 8,122 km of rivers and streams, and 31 major lakes and ponds. The area drained is agriculturally diverse and contains highly urbanized Rochester, NY. Thus there have been significant water quality issues, involving sediment, nutrients, and fish consumption advisories (NYSDEC 2004).

Figure 1. Geographic location of the Genesee River.

Biological and chemical monitoring by the New York State Department of Environmental Conservation in the Genesee River has indicated an increasing improvement in river habitat and water quality in the past 20 years (Elliott 1997, Sherwood 2003). As of 2000, the USEPA 8

watershed indicator rating of the river was 3: less serious problems and low vulnerability.

Figure 2. Lower Falls of the Genesee River. First barrier to migration.

There is a 33.5 m waterfall at river kilometer 10.2 (Figure 2.) restricting the potential sturgeon habitat to the lower Genesee from the falls north to Lake Ontario. Assessment of changing physical and biotic habitat conditions is critical to fisheries and environmental management projects, including restoration of native species. In an account of the early history of the Genesee River, very large sturgeon (45 to 70 kg) existed in the lower river and congregations of spawning sturgeon were reported at the falls (Black 1944, Clune 1963, Carlson 1995). However there have been no records of spawning sturgeon in the river since the 1920’s (Greeley 1927, Carlson 1995). Management of a threatened species includes a careful assessment of the habitats in which the species was once common (Hess 1996, Bain and Stevenson 1999, Ireland et al. 2002). The reported improvement in Genesee River water quality has created a window of opportunity for lake sturgeon restoration and enhancement in this river in keeping with the Lake Ontario fish community objectives (Stewart et al 1999, Carlson 2000).

Project Significance to the Rochester RAP and the Lake Ontario LaMP This project has direct significance to the Rochester Embayment Remedial Action Plan (RERAP) and the Lake Ontario Lake Management Plan (USEPA 2002). The Area of Concern (AOC) addressed in the RERAP is defined as: "that portion of Lake Ontario inside a contiguous line between Nine Mile Point (east end) and Bogus Point (west end) and the lower Genesee River, from the lower falls to the mouth" (Figure 3.)

Figure 3. Rochester AOC and potential sturgeon habitat.

Habitat degradation and degraded aquatic populations have been identified as use impairments in the Stage I RERAP. The Habitat Oversight Committee, which addressed habitat degradation, realized that much of the degradation is irreversible. Stage II was completed in 1997 and documented ongoing programs and remedial measures to restore water quality. In addition, Stage II described studies and monitoring programs needed to complete identification 10

of problems and track progress in restoration. This process is long-term, spanning 10 to 30 years or more, which is how this lake sturgeon research project will directly assist the RERAP process. Biological indicators such as lake sturgeon are being used to set de-listing criterion for the AOC. One such de-listing criteria states that, when lake sturgeon of all life stages inhabit the Genesee River or when the physical and biological habitat is suitable for lake sturgeon, the impairment can be removed. This criteria is based on 3-5 year monitoring of lake sturgeon presence and studying habitat suitability (Threader et al. 1998). Initiating a lake sturgeon research project and monitoring their utilization (i.e. feeding, growth, eventually spawning) and habitat conditions in the river will provide important information regarding the habitat quality in the AOC.

Problem Definition: The Genesee River as Sturgeon Habitat

Pre-stocking Research in the Genesee:

Successful species restoration requires an assessment of any remnant population and the evaluation of the availability and quality of habitat for all life stages of the threatened species over multiple years (Grogan and Boreman 1998). Due to the infrequent spawning periodicity of lake sturgeon, 5 consecutive years were sampled to test the conclusion that no lake sturgeon were using the Genesee River habitat. Extensive gill netting during optimal spawning conditions each year from 1999 to 2002 did not detect sturgeon. Thus, supporting the conclusion that there were no adult lake sturgeon using the Genesee River, and thus confirming the population classification as extirpated (Lowie et al. 2000). An evaluation of spring spawning habitat and adult and juvenile summer foraging habitat was conducted along transects spaced throughout the accessible part of the Genesee River 1999 to 2002, as stage one of work in the Genesee River (Dittman 2006). Habitats were sampled and mapped from Lake Ontario to the first natural barrier (Lower Falls). Water flow, depth, temperature, and substrate characteristics were recorded. Habitat data were rated using a surgeon habitat suitability index model (HSI) developed for Ontario rivers (Threader et al. 1998). This is an empirical model that used several suitability index curves of environmental variables to rate the habitat suitability. Spawning habitat variables in the HSI were water temperature (10 to150C), depth 2-6 m, rocky to gravelly substrate composition, and water velocities >1 m/sec.

Probable spawning habitat was found from the Lower Falls to the down river end of Seth Green Island. The substrate consisted of boulders and cobbles at depths of 0.5-2.5 m. Spring water velocities in 1999 ranged from 50 to 240 cm/sec with temperatures between 10 and 180C. Spring water velocities in May 2000 ranged from 50 to 150 cm/sec at similar temperatures. Analysis with the HSI model rated this area in 1999 and 2000 as good or optimal spawning habitat (Dittman 2006). Foraging habitat HSI variables for adults include silt and sand as the optimal substrates and benthic production of macroinvertebrates, while juvenile foraging variables also included as optimal water velocities between 10 and 40 cm/sec and depths between 1 and 7 meters. Probable foraging habitat was found from Seth Green Island to the river mouth area (rkm 1 to 9.2). Substrates included sand, silt, silty clay, and sandy gravel at depths of 2 to 7 m. Water velocities were 0 to 50 cm/sec. Application of the HSI model resulted in rating this area as good or optimal foraging habitat for adults and juveniles. A pre-stocking assessment of the benthic community as a potential food resource found Megaloptera, Ephemeroptera, Mollusca, and high densities of Chironomidae and Oligochaeta. The highest densities of these animals were in the silty-sandy dredged areas within four km of Lake Ontario. The highest diversity of invertebrates was found in the most upstream sandy-silty sites. The burrowing mayfly (Hexagenia sp.), which is considered an indicator of ecosystem health (USEPA 2002), was found in low numbers in the upstream transects between rkm 8.3 and 9.2. Based on this pre-stocking habitat evaluation, the Genesee River appeared to provide good physical and biological juvenile lake sturgeon habitat (Dittman 2006).

Experimental Stocking as a Habitat Evaluation Tool:

One management tool used in threatened species conservation and restoration is the experimental stocking of hatchery-reared fish into areas where the original populations have been extirpated for an applied evaluation of the current habitat suitability (Young 1999, Wiley 1999, Secor et al. 2000, Bearlin et al. 2002, Gross et al. 2002, Ireland et al. 2002). In the short term, there is a two-phase process that would likely occur regarding the experimentally stocked lake sturgeon in the Genesee. For the first year, the likelihood they would remain in the river was very high. In later years, they likely will move downstream within 12

the river. How far they would move in a given year was unknown. To accommodate the loss of some sturgeon to Lake Ontario, stocking was done for two years to ensure adequate fish presence for the habitat use evaluation. This decision was based on information from a past stocked lake sturgeon study conducted by USFWS-LGLFRO (Schlueter 2000). That study showed that while many newly stocked individuals in the Oswegatchie River remaining fairly close to the stocking sites, some moved as much as 70 km downstream. Fish that initially stayed close slowly moved downstream, possibly cued by population density or changing habitat requirements as they grew. In the St. Louis River, Wisconsin, stocked lake sturgeon migrated downstream that season; but remained in the river for four years before entering Lake Superior (Schram et al. 1999). There is little additional information on the movements of stocked lake sturgeon, which makes it difficult to predict how long they will stay in the Genesee River system. Under natural conditions it is expected that the sturgeon move out of Genesee River into the near shore habitats of Lake Ontario for foraging after a few years. The expected degree of success in being able to accurately locate marked sturgeon and identify habitat use patterns with the use of nets was high. From tagged individuals, recapture data can show how long these individuals remain within certain habitats. Lastly, habitat variables were collected in areas with high and low catch rates to determine habitat differences and suggest habitat suitability or preference. This method was also applied in the St. Louis River investigation of stocked lake sturgeon (Schram et al. 1999) and in a study of wild juvenile lake sturgeon in the St. Lawrence River (Nilo et al. 1996).

OBJECTIVES

The primary objectives of this project were: • Measurement of habitat use by experimentally stocked juvenile lake sturgeon. • Evaluation of the predictions of the sturgeon HSI model generated using data from previous habitat assessment by comparison with the habitat use by experimentally stocked juveniles. Hypothesis: • The Genesee River contains habitats that juvenile sturgeon find suitable for use as nursery habitat. 13

Evaluation of post-stocking survival and habitat use by hatchery-reared fish is essential for any efficient restoration program (Secor et al. 2000, Ireland et al. 2002, Gerrity 2005). Studies that generate information to aid in producing juvenile sturgeon that are best able to survive in the wild are critically needed (Wiley 1999). This project is focused on lake sturgeon population assessment, habitat use, and possible restoration in a southern Lake Ontario tributary, but results are applicable to many historic sturgeon waters. Results of this research in the Genesee River provide information and validation of methods needed for future steps in the restoration and enhancement of lake sturgeon in Lake Ontario and its tributaries, and will have implications for sturgeon restoration and management plans across the Great Lakes Basin (Auer 2000, Holey et al. 2000, Hickey 2003).

METHODS

Fish Rearing and Experimental Stocking

An effort by the NYS DEC in the St. Lawrence River below Moses Saunders Dam is ongoing to collect adults at the time of spawning (Carlson 2000, Carlson 2005). Gillnets were set overnight in sites in the channel to the south of Moses Saunders Dam (Klindt and Town, 2004). In both 2003 and 2004, the NYSDEC standard procedure for sturgeon egg take was followed (Klindt 2005). Sturgeon were reared through the summer at the NYSDEC Oneida Fish Cultural Station in Constantia. Levels of production in 2003 and 2004 led to prioritization of stocking sites across New York. Nine hundred fingerling lake sturgeon were stocked in the lower Genesee River in September 2003 and 1000 fingerlings were stocked in September 2004. An informal effort was made in the hatchery to divert the smallest fish to other waters. Prior to being released, all stocked lake sturgeon received a permanent mark by removing two lateral scutes from one side of the fish with a scalpel (Figure 4). Marks were right 1st and 2nd for the 03YC and right 4th and 5th for the 04YC. This allows identification during this study and will allow identification of stocked lake sturgeon in the river for at least 4 years.

Figure 4. Scute marking sturgeon. Experimental stocking occurred in September of 2003 and 2004. The hatchery truck transported the fingerlings from Constantia, NY to the boat ramp at Lake Ontario Park in Rochester, where they were transferred to aerated live wells on USFWS and USGS boats. The fish were transported upstream to the stocking site (Figure 5.) and released.

Figure 5. Stocking site in the Genesee River (rkm 9.1), just downstream of Seth Green Island. 15

The stocking site was selected as far upstream as possible in the good quality juvenile sturgeon habitat. This site was at the fishing access off St. Paul Boulevard, just downstream of Seth Green Island, at rkm 9.2. This is a sandy-silty site, < 1 m deep, and out of the main flow of the river. This site was selected to give the hatchery fish a protected place to become accustomed to the river. It is 1 km downstream of the Lower Falls and the Rochester Gas and Electric power project (RG&E).

Evaluation of Habitat Use by Experimentally Stocked Juvenile Lake Sturgeon

A standardized mark - recapture protocol was followed during the capture and habitat use phase of the project, using experimental gillnets (Pine et al. 2003). The river was divided into six reaches from the waterfall downstream to the first marina at Lake Ontario. An assessment using standardized gill netting from river km 2.5 to 9.1 was conducted with experimental gill nets, 38 m long and 2.4 m deep, with 5 panels of graduated bar mesh sizes 2.54 cm to 7.62 cm. The first reach was the area from the falls to the Route 104 Bridge (rkm 10.2 to 8.4). This area is primarily shallow and rocky, with faster flow than the downstream reaches. Therefore, only gillnetting in the slower edges was conducted in this area. Boat electrofishing was conducted one week after stocking in 2003 as a trial collection method. Unfortunately, while we caught many large salmon, the conductivity and lack of visibility in the Genesee River reduced effectiveness to zero for benthic fishes, and use of electrofishing was discontinued. The other five sections were sampled from the Route 104 Bridge to the marina at river kilometer 2.1. Up to eight monofilament, 38 m long, 2.4 m deep, gillnets, ranging in size from 5 cm to 15 cm stretched mesh were deployed periodically (monthly during field season) after stocking. Initial sampling was September to November 2003. Sampling began again during the late-winter to early-spring period, as weather and river conditions allowed. Presence and habitat use evaluation was conducted during May to October of 2004 and May to August of 2005. Gillnets were fished for 24 hour periods for two to four days each month throughout these sampling periods. Due to higher catch rates of lake sturgeon in the smallest mesh (5 cm stretched) during Fall 2003; additional nets with 4 cm to 10 cm stretch mesh, 38 m long and 1.83 m deep were also used in 2004 and 2005.

Figure 6. Lake Sturgeon in the gill net.

The standard six nets were fished approximately 24 hrs at a time in their respective river reaches. Nets were pulled up, all fish removed, and then reset. Between sampling days they were often relocated to sample different areas within the reach, or due to excessive catch of other fish in a given location. Juvenile lake sturgeon were held in an aerated holding tank on the boat until measured, (total length, girth, and weight).

Figure 7. Weighing Sturgeon 17

Captured lake sturgeon were tagged with a yellow FloyTM spaghetti tag for individual identification upon repeated recapture (Pine et al. 2003), photographed, and returned to the river within 25 m of the capture location. Each tag has a unique number and a phone number.

Figure 8. Tagging

Recaptured lake sturgeon provided snapshots of distribution, movement and individual growth rates. Distribution and movement data were used to determine residence locations and associated habitat preferences. Capture and recapture data were used to compare habitat preferences within and between reaches in the river.

Habitat Assessment

Habitat assessment and suitability estimates are essential for any ecological community evaluation or restoration project (Bain and Stevenson 1999). At each gillnet site, Global Positioning Systems (GPS) location, named site location, and habitat conditions were recorded. Habitat variables included water temperature, velocity, depth, dissolved oxygen (DO) concentration, and substrate type. Temperature, DO, pH, and conductivity were measured using a YSI 6600 multiparameter sonde. Water velocity was measured at a depth of 1 m from the surface with a Marsh-McBirney current meter attached to a cable. After successful sturgeon captures, physical and biological community parameters were measured at that gillnet site. Sediment and benthic community sampling was conducted with a petite Ponar sampler (0.0232 m2, Figure 9.). The ponar was dropped to the riverbed, activated to close its jaws, and retrieved. The integrity of each sample was determined visually when the grab was brought into

the boat. Samples that were compromised because the jaws of the ponar were not completely closed were discarded and a replacement sample was collected. The ponar was positioned over a large sieve (0.5 mm mesh), opened and the sediment in it flushed into the sieve with river water. This sieve allowed the fine sediment to be washed out and macroinvertebrates retained. Samples taken for benthic community analysis were preserved in 10% buffered formalin, and after a week stored in 70% alcohol. In the laboratory, all organisms were picked from the sample using a dissecting microscope and identified to the lowest functional taxonomic level (Peckarsky et al. 1990, Moulton et al. 2000). Sediment type was quantified on a modified Wentworth scale (Wentworth 1922). Transect samples were analyzed for percentage composition.

Figure 9. Ponar in action.

During the spring and summer of 2005, a gastric lavage technique modified from Brosse et al. 2002, was performed on a subset of captured individuals to characterize the diet of stocked lake sturgeon. Sturgeon were knocked out with a common fish tranquillizer. A lift pump was used to flush river water down a tube, into the fish stomach, and then wash the food items out into a field tray (Figure 10). Fish were held in the river until they recovered sufficiently to swim away. During laboratory experiments to develop the technique, there was no mortality, and the lavaged fish fed normally within a few hours. Flushed stomach contents were preserved in 92 % alcohol in a cup. Each cup was labeled with date, site, a unique serial number of the sample site, and tag number of the sturgeon.

All macroinvertebrates were removed from the samples, counted, and identified to the lowest functional taxonomic level (Peckarsky et al. 1990, Moulton et al. 2000), using a dissecting microscope. Diet analysis was completed using standard techniques.

Figure 10. Stomach Flushing.

A habitat suitability index model has been developed for lake sturgeon (Threader et al. 1998) using an extensive review of the literature on lake sturgeon ecology and input by numerous sturgeon researchers. To use this model to evaluate the extent of habitats suitable for juvenile sturgeon in the Genesee, habitat data were collected in equally spaced transects from just downstream of the Seth Green Island, downstream to the marina areas near the river mouth, which is dredged for navigation. The standard model variables include: substrate type, water depth, water velocity, and water temperature. In addition, as an environmental quality variable and as a measure of food availability, the composition and densities of the benthic macroinvertebrate community including Ephemeroptera, Diptera, and Trichoptera, were measured using standard techniques (Reice and Wohlenberg 1993, Chiasson et al. 1997). Global Positioning Systems (GPS) was used to map the habitat data and locations in the river.

RESULTS Measurement of habitat use by experimentally stocked juvenile lake sturgeon.

Despite the possibility based on other sturgeon stocking studies, that the most likely outcome of the experimental stocking would be a quick downstream exit of most or all of the stocked fish to Lake Ontario, many fish survived the introduction into the Genesee and remained

in the river. From September of 2003 to October 2004, sturgeon were captured 167 times, including initial captures and 12 recaptures. For the 03YC the Schnabel population estimate (assuming 100% over winter survival) was 366 individuals (95 % CI 248 to 563) in the river (as of October 2004), more than one year after introduction. From May to August 2005 juvenile sturgeon were captured 441 times, including initial captures and 75 recaptures. These were both the 03YC and 04YC fish. The Schnabel population estimate for the 03YC (assuming 100% over winter survival) as of August of 2005 was 392 fish (95% CI 319-481) individuals still present out of the 900 fish released in September 2003, 23 months after introduction. The Schnabel population estimate for the 04YC fish (assuming 100% over winter survival) as of August of 2005 was 679 fish (95% CI 498-952) still present in the river 11 months after 1,000 fish were released.

5 5 2003 2004 004 004 004

9/24/ 5/11/ 8/2/2 8/3/2 8/3/2 8/5/2004 9/1/2004 10/19/200410/20/200410/21/20046/13/20057/11/20057/11/20057/13/20057/14/20058/1/200 8/4/200 0 1= Above 104 Bridge 2= Below 104 Bridge 3= near Kodak 4= Deep hole 5= Waterfalls 6= Barge area dT i B i 1

3 Site

Figure 11. Capture locations of 03YC sturgeon, from just after stocking to August of 2005. Nine juveniles were captured during the initial Fall 2003 assessment. All were tangled in the 2.5 cm mesh of the gill net. Eight of these fish were captured at site 2 (rkm 8.2) and the remaining one was captured at site 4 (rkm 6, Figure 11). Variable capture patterns were seen among the river sites during the rest of the study Figures 11, 12 and 15.

Figure 12. The most successful capture sites in the Genesee are indicated by bold numbers. 22

The successful capture sites were spread through the river (Figure 12). The most successful capture site was the first deep area downstream of the release site, (Below Route 104 bridge, Site 2, rkm 8.2). It averages over 6 m depth and has gravelly substrate with the shells of dead mollusks abundant (Figure 13).

Figure 13. Below Route 104 Bridge. Site # 2.

Figure 14. 30 Ft Hole, Site #4. The second most successful capture site (Site 4, 30 ft Hole, rkm 6.2) was a deeper area (9 23

to 10 m) with gravelly-rocky substrate on an outside river bend (Figure 14). During the 2005 field season, the majority of the 441 captures were in the deepest parts of each sampled river reach (5 to 10 m), were the most successful sites were the same as in 2004. For the most part, these sites had gravelly to sandy substrates and were spread throughout the assessment area. The site where the 04YC sturgeon were captured were similar to sites where the 03YC fish were found (Figure 15), with more found at sites 1 and 3. Six fish were captured in October of 2004. They were captured at site 2 (rkm 8.2), site 3 (rkm 6.9) and site 6 (rkm 2.5). This was a different pattern than shown by the 03YC in their first October in the river.

005 005 005 005 005 05 05 05 05

10/18/20045/19/20056/13/20057/11/20057/11/2 7/11/2 7/12/2 7/12/20057/13/20057/13/20057/14/2 7/14/2 8/1/20 8/2/20058/2/20058/3/20058/4/20 8/4/20 8/4/20 0 1= Above 104 Bridge, 2= Below 104 Bridge, 3= near Kodak, 4= Deep Hole, 5= Waterfalls, 6= Barge area

3 Site

Figure 15. Capture locations of 04YC sturgeon.

Many sturgeon were recaptured in the same location as the initial capture, 37 of the 03YC and 15 of the 04YC did not change locations between captures. The locations of these repeat recapture sites reflect the overall pattern of most successful capture sites, primarily sites 2 and 4 (Figure 11). Many fish moved downstream and upstream between repeat captures. Twelve of the 03 YC moved downstream and much of the movement was from sites 2 and 4 to downstream sites (Figure 16). However; eleven of them did move upstream, from site 4 to site 2 (Figure 17).

7 w inter 2004-5

4 Site 3 6= Barge area and Turning Basin 2 5= Waterfalls 4= Deep hole 3= near Kodak 1 2= Below 104 Bridge 1= Above 104 Bridge

5 004 004 004 004 005 005 005 005 005 00 2 2004 2004 7/7/2 8/2/2 8/4/2004 /20/ /16/2 8/2/2005 8/4/2005 6/15/ 8/31/2 5 5/18/2 6/13/2 6/16/2 7/12/2 7/14/2 10/18/ 10

Figure 16. 03YC moving downstream, 04 to 05. Connected symbols represent individual fish.

7 w inter 2004-2005 6= Barge area 6 and Turning Basin 5= Waterfalls 5 4= Deep hole 3= near Kodak 4 2= Below 104 Bridge 1= Above 104 Bridge Site 3

04 04 05 004 004 005 005 005 /2 /2 /2 /2 /2005 /2005 /2 /2005 8/2004 0/2004 7/7/20 8/2/20 8/4/2004 8/2/20 8/4/2005 6/15 8/31 5/16 5/18 6/13 6/16 7/12 7/14 10/1 10/2

Figure 17. 03YC moving upstream 2004 to 2005. Connected symbols represent individual fish.

In 2005 the 03YC fish primarily moved upstream, 14 individuals (Figure 18). Only 4 moved downstream during the same period. Equal but small numbers of the 04YC fish moved up and downstream in 2005, 7 moved downstream and 6 moved upstream.

4 6= Barge area

Site and Turning Basin 3 5= Waterfalls 4= Deep hole 2 3= near Kodak 2= Below 104 Bridge 1 1= Above 104 Bridge

05 05 05 005 005 005 005 005 005 005 /2005 /2005 /2 /2 /2 /2005 /2005 /2005 /2 /2 /2 /2 8/1/20 8/2/20 8/3/20 8/4/2005 5/16 5/17 5/18 5/19 6/13 6/15 6/16 7/11 7/12 7/13 7/14 8/18

Figure 18. 03YC moving upstream in 2005. Connected symbols represent individual fish.

Habitat Assessment: Assessment of the quality and suitability of Genesee River fish habitat for lake sturgeon by standard assessment methods and sturgeon HSI proceeded in conjunction with the juvenile sturgeon mark-recapture experiment. In November 2004 spaced transects were sampled to characterize the sediment characteristics and invertebrate community of the target area. The sample locations were numbered from 1 at the most upstream site to 23 at the mouth of the river. Sediment analysis results were that cobble and gravel were more abundant in the upriver sites (Table 1).

Figure 19. Locations of spaced environmental samples in the lower Genesee River. The locations of transects 1, 16, and 23 are shown for reference.

Table 1. Composition of sediment in spaced transects in the lower Genesee River, November 2004. Sample locations are shown in Figure 19. Depth Course Medium Fine Silt & Location Name Site (m) Gravel Sand Sand Sand Clay Below Seth Green 1 2.1 0.17 0.08 0.12 0.51 0.12 East Side Above 104 3 2 0.29 0.06 0.02 0.2 0.43 West Side Below 104 4 4.3 0 0.02 0.19 0.36 0.43 West Below TLAS Tree 5 3.3 0 0 0.03 0.87 0.1 Kodak at Walkway 6 5 0.01 0.01 0.01 0.51 0.46 Kodak at Willows 7 3.1 0 0 0.02 0.66 0.32 Across Kodak Dock 8 4 0.07 0.23 0.22 0.18 0.3 River Bend Below Kodak 9 4 0.02 0.05 0.47 0.44 0.02 E Across from Flume 10 2.1 0 0 0.02 0.17 0.81 E Bend Below Flume 11 1.6 0 0 0 0.75 0.25 E Above Deep Hole 12 2 0 0.02 0 0.23 0.75 E Across Deep Hole 13 2.1 0 0 0.01 0.7 0.29 E Side Dock 14 2.1 0 0 0.01 0.21 0.78 2nd Willow 15 2.4 0 0.01 0.05 0.32 0.62 Water Falls 16 6 0 0.08 0.06 0.07 0.79 Turning Basin 17 1 0 0 0.01 0.02 0.97 Below Turning Basin 18 4.9 0 0 0.01 0.2 0.79 Above Barge 19 4.9 0 0.01 0.01 0.13 0.85 Marina 20 3.1 0.04 0.4 0.11 0.07 0.38 Above Memorial Bridge 21 5 0 0.05 0.02 0.12 0.81 Below Memorial Bridge 22 2 0 0 0.01 0.02 0.97 Swing Bridge 23 3.1 0 0.02 0.18 0.28 0.52

From the middle of the target area to the harbor area sites had a mix of sandy and silty substrates (transects 13 to 23, Table 1). Some sites have a large amount of wood debris, (Deep Hole, transect 13), or leaves (Large Dock, transect 14). 28

Invertebrate community composition samples were taken at the same time in the same locations. Benthic invertebrate abundance was fairly high. The two most common and abundant taxa were Chironomidae and Oligochaeta (Tables 2 and 3). Amphipoda and Sphaeriidae were also common, with lower numbers of other insect larvae and macroinvertebrates.

Table 2. Invertebrate composition and #/m2 in spaced transects in the target area. Locations are shown in Figure 19. Site numbers correspond to the numbers in Table 1. Site # 1 2 3 4 5 6 7 8 9 10 11 12 Chironomidae - 87 130 130 606 130 303 1,039 - 4,804 46 693 Oligochaeta 43 - 390 995 1,428 432 390 2,640 87 1,385 736 43 Amphipoda - 87 - 43 346 43 476 - 43 43 43 - Sphaeriidae - - 87 43 87 173 - 649 - 87 43 43 D. polymorpha - 25 ------Gastropoda - - 1,082 43 - - - 130 - - 130 87 Other Diptera - - - 43 - - - - - 43 43 - Ostracoda - - 173 ------43 - Plecoptera - - - 43 43 ------Trichoptera - - - - 43 ------Odonata ------43 - - - 43 Coleoptera - 43 - - - - 87 - - 130 - - Hydracarina 43 ------Ceratopogonidae - - - - - 43 ------Other - - - 43 ------87 -

Table 3. Invertebrate composition and #/m2 in spaced transects in the target area. Locations are shown in Figure 19. Site numbers correspond to the numbers in Table 1. Site # 13 14 15 16 17 18 19 20 21 22 23 Chironomidae 5,150 606 856 216 3,246 3,029 1,601 173 1,774 1,644 1,342 Oligochaeta 65 26 33 31 222 88 106 11 73 99 253 Amphipoda 43 - - 606 592 - 87 303 43 43 - Sphaeriidae - - 43 - 692 346 866 649 - 260 563 D. polymorpha - - - 2,770 - - 173 173 - - - Gastropoda - 130 - 43 - 43 260 - 173 173 43 Diptera 216 - - - 216 - - - - - 43 Ostracoda ------43 - - - - Trichoptera - - 43 - - - - 43 43 43 43 Odonata - - - 43 - 43 43 - 87 - - Coleoptera 43 43 ------43 - Hydracarina 87 - - - - - 43 - 43 - - Ceratopogonidae ------130 - Other - 43 43 - - - 130 43 - - -

In October 2004 sediment analysis was done in the sites of the most successful sturgeon captures (Figure 12). In general these sites had gravel, mostly sand, and little silt and clay (Figure 20, Table 4).

Figure 20. Large fraction of sediment from the 30 ft Hole, rkm 6.3.

Table 4. Sediment composition of the most successful sturgeon capture locations Course Medium Fine Silt & Location Depth (m) Gravel Sand Sand Sand Clay Seth Green Isl. Site 1 2 0 0.02 0.14 0.54 0.3 Below 104 Site 1 6.4 0.02 0.45 0.29 0.22 0.02 LAS tree below 104, Site 2 6 0.01 0.17 0.5 0.31 0.01 Kodak Site 3 4.9 0.01 0.14 0.59 0.25 0.01 Flume Site 3 6 0 0.01 0.13 0.81 0.05 Deep Hole Site 4 8.5 0 0.01 0.79 0.2 0 Water Fall, Site 5 8.5 0.01 0.09 0.81 0.09 0 Large Dock 5.5 0 0 0 0.37 0.63

Analysis of the invertebrate community at these sites showed some zebra mussels (D. polymorpha, Figure 21). The detection of these invasive mussels was dependent on the sample including small cobbles or branches that are substrate for them. In some sites a significant part of the substrate sample consisted of dead mussel and snail shells (Below 104 for example). The other common groups were Chironomidae, Oligochaeta, and Amphipoda with other insect larvae and macroinvertebrates at lower densities (Figure 21).

104 Bridge October 04

200 150 100 50

Number / m sq / m Number 0

e a ra pha da da era po i t te chaeta nionid op o U h lig Plecopter Amphi O hironom Tric D. polymor C Ephemerop

Kodak October 04

600 500 400 300 200 100

Number / m sq Number 0

e a a da d ta ida o od ter ni c p Other ro nio dona phipoda om stra strop e U O orixidae m ligochaeta ron O a m C A Sphaeriidae O hi G he Trichoptera C Ep

30 ft Hole October 04

700 600 500 400 300 200

Number / m sq Number 100 0 Amphipoda Sphaeriidae Oligochaeta Chironomidae Gastropoda Trichoptera Other

Waterfall October 04 300 200 100 0 Number / m sq

e ta ae a e d d iida i ha m morpha o Diptera y haer goc stropo ol ron a p Amphipoda Sp Oli G Trichoptera D. Chi

Figure 21. Taxa and density of macroinvertebrates at sturgeon capture sites, October 2004.

Tables 5, 6, 7 and 8 contain representative the physical variables of capture locations along with the number of sturgeon captured on that date at that location. Full details of all locations and physical variables measured will be available in a data archive.

Table 5. Physical factors by site with sturgeon catch, November 2004. Sturgeon Depth Temp. Cond. DO pH ORP Turb. Chlor. Day Pulled Site Name Site # Captured (m) 10/20/2004 104 Bridge 2 4 6.1 10.46 807 11.02 8.15 46.1 650 1.1 LAS tree 2 0 6.1 10.5 810 10.93 8.1 43.2 640 1.1 A Kodak 3 0 7.6 10.78 827 10.82 8.09 34.6 630 1.1 Deep Hole 4 11 9.1 10.46 807 11.1 8.08 660 1.3 Waterfall 5 0 9.1 10.6 666 11.08 8.12 44.5 625 1.1 Above Barge 6 5 6.1 10.75 825 12.86 8.1 35.9 648 1.4 10/21/2004 104 Bridge 2 4 6.7 10.48 680 10.96 8.12 28 562 1.7 Kodak 2 1 4.3 10.49 680 11.14 8.12 32.4 596 1 Flume 3 3 6.1 10.79 688 11.07 8.12 37.3 520 0.8 Deep Hole 4 2 7.6 10.79 688 10.78 8.12 42.7 467 0.7 Waterfall 5 3 7.6 10.88 672 11.04 8.11 46.2 503 1 Above Barge 6 0 6 10.79 704 10.67 8.11 49 519 1 10/22/2004 104 Bridge 2 1 5.8 10.22 647 11.2 8.14 36.2 626 1 Kodak 2 1 4.6 10.21 646 11.27 8.14 38 620 1.1 Flume 3 3 6.1 10.57 661 11.08 8.12 41.1 628 1 Deep Hole 4 1 9.1 10.6 665 11.08 8.12 44.5 625 1.1 Waterfall 5 5 8.5 10.64 667 11.22 8.14 51.3 614 1.5 Above Barge 6 1 6.1 10.91 677 10.9 8.13 52.9 614 1.2

Table 6. Physical Factors by site with sturgeon catch, May 05. Flow Date Site Name Catch Depth Temp. Cond. DO pH ORP (m/sec) Turb. Chlor. 5/16/2005 Seth Green 0 1.7 15.2 492 10.31 8.04 83.1 0.9 x x LAS tree 2 6.1 15.1 495 10.6 8.05 64.1 0.16 x x Flume 0 5.8 15.3 622 10.2 7.99 21.98 0.23 x x 30ft hole 0 8.8 15.3 506 10.1 7.96 14.2 0.16 x x Falls 0 7.6 15.3 509 9.24 7.9 15.1 0.11 x x Above Barge 0 6.4 15.4 516 8.92 7.91 14.2 0.14 x x 5/17/2005 Seth Green 0 1.8 x x x x x 0.37 x x LAS tree 2 6.1 14.9 599 10.63 8.08 56.4 0.18 7.3 4.2 Flume 0 6.1 15.1 618 11.66 8.04 23.1 0.15 8.3 3.3 30ft hole 2 8.8 15.4 638 11.77 8.02 18.21 0.05 7.5 3.2 Falls 0 8.5 15.2 507 10.31 7.98 17 0.1 x x Above Barge 3 7.6 15.6 676 11.85 8.07 x 0.05 8.2 4 5/18/2005 Below 104 Br. 2 4.5 15.5 594 9.09 8.01 x x 4.9 4.2 LAS tree 1 5.2 15.5 592 9.97 8.1 x x 6 3.1 Kodak 0 4.8 15.6 615 10.83 8.08 x x 6.4 3.2 Flume 0 6.7 15.6 610 11.07 8.21 x x 7.2 2.9 30ft hole 5 8.5 16.1 610 10.61 8.21 x x 4.5 2.7 Falls 0 8.2 15.7 611 11.28 8.13 x x 5.8 3 Above Barge 7 6.4 16.1 617 10.98 8.13 x x 5.4 3.8

Table 7. Physical Factors by site with sturgeon catch, July 2005 Flow Day Pulled Site Site # Catch Depth Temp Cond. DO pH ORP (m/sec) 7/12/2005Above 104 1 8 1 24.2 473 9.48 7.69 69.4 0.04 Below 104 2 28 5.1 25.05 463 9.22 7.79 28.1 0.12 LAS Tree 2 15 5.8 25.82 457 9.01 7.85 26.6 0.01 Kodak 3 14 4.3 26.2 486 9.03 7.85 3.8 x Falls 5 13 8.5 26.28 495 9.03 7.77 12.9 x Above Barge 6 06.7xxxxxx 7/13/2005Above 104 1 8 3 25.41 409 8.52 7.73 8.1 0.11 Below 104 2 12 4.9 25.54 411 8.02 7.76 9.2 0.08 LAS Tree 2 5 5.5 26.11 406 7.56 7.83 -6.2 0.07 Kodak 3 14 5.2 25.89 435 8 7.66 13.2 0.05 Falls 5 5 8.2 26.98 437 8.26 7.68 20.8 0.07 Above Barge 6 06.4xxxxxx 7/14/2005Above 104 1 8 3 26.68 443 8.41 7.82 -8 0.04 Below 104 2 18 4.6 27.29 442 8.22 7.85 31.4 x LAS Tree 3 10 5.5 27.16 441 8.36 7.86 -7.4 0.05 Kodak 3 13 5.2 28.55 447 8.37 7.85 -6 0.07 Falls 5 1 8.5 26.69 446 8.13 7.63 12.5 0.06 Above Barge 6 16.4xxxxxx 7/15/2005Above 104 1 5 2.8 27.13 430 8.56 7.88 -12.6 0.13 Below 104 2 12 5.5 27.16 431 8.35 7.87 36.5 x LAS Tree 2 2 5.4 27.53 431 8.65 7.9 -5.8 0.04 Kodak 3 7 5.3 27.67 444 8.4 7.89 -6 0.08 Falls 5 13 7.7 26.98 457 8.09 7.78 6.8 0.16 Above Barge 6 2 6.2 27.96 435 8.2 7.89 1.6 x

Table 8. Physical Factors by site with sturgeon catch, August 2005 Flow Date Site Name Site # Catch Depth Temp Cond. DO pH ORP (m/sec) 8/1/2005 Below 104 2 9 5.8 25.94 576 9.3 9.59 73 0.13 30ft hole 4 33 9.1 26.29 596 10 9.63 68 0.05 8/2/2005 Above 104 1 4 2.7 26.42 610 7.6 9.58 56 0.04 Kodak 3 3 3.3 27.23 612 7.1 9.48 50 0.006 Flume 3 1 6.7 27.43 609 7.2 9.41 47 0.003 Falls 5 16 8.5 27.71 585 9.2 9.64 44 0 Large Dock 5 1 3.3 30.04 590 8.8 9.66 18 0 Above Barge 6 5 6.1 28.96 583 11 9.93 21 0 8/4/2005 Above 104 1 1 2.7 26.9 594 7.3 9.58 32.5 0.1 Kodak 3 3 5.1 27.6 636 6.9 9.46 46.8 0.17 30ft hole 4 10 8.8 27.7 645 7.7 9.59 54.3 0.1 Falls 5 10 8.5 28.07 648 8 9.67 67.1 0.1 Large Dock 5 1 3.3 27.87 646 8.8 9.67 51.3 0 Above Barge 6 1 6.7 27.28 620 8.3 9.59 60.7 x 8/5/2005 Below 104 2 10 4.9 27.8 602 8.4 9.57 33.5 0.05 Kodak 3 4 4.9 27.86 639 7.9 9.35 57 0 30ft hole 4 15 7.8 28.69 617 9.1 9.58 42.3 x Falls 5 5 6.1 28.39 627 10 9.69 49.4 0.12 Large Dock 5 4 3.3 28.33 627 10 9.75 22.7 0.25 Above Barge 6 6 6.7 28 628 11 9.82 25.9 0.2

Sturgeon were present in all sections of the river that had been rated as good foraging habitat (Tables 5, 6, 7 and 8). Of all of the physical variables, only depth has any good correspondence with the successful captures. In November 2004, at temperature just above 10oC sturgeon were spread fairly evenly in the river (Table 5). In May 2005, there were few sturgeon caught and they were concentrated at the two deeper sites and the most downstream site. (Table 6). In the summer months the number of sturgeon caught at a given site was not predictable using physical variables other than depth (Tables 7 and 8). Even depth only predicted that some sturgeon would be caught, but not if it would be 1 fish or 15 fish.

Genesee River Benthos June 2005 Oligochaeta Other 26.6% Collembola 0.2% 0.1%

Copepoda 0.2% Sphaeriidae 1.1% Coleoptera 0.1% Amphipoda Chironomidae D. polymorpha 2.3% 67.2% 2.1%

Genesee River Benthos July 2005 Amphipoda D. polymorpha 5.5% 26.2% Ostracoda 0.7% Trichoptera 0.6%

Unionid 7.3%

Chironomidae Other 37.1% 0.0%

Oligochaeta 22.0%

Genesee River Benthos August 2005 D. polymorpha Gastropoda 3.7% 3.1%

Chironomidae Unionid 56.6% 3.2%

Other 0.0% Oligochaeta 32.5%

Figure 22. Invertebrate community composition, Summer 2005.

Assessment of the invertebrate communities was done during the same time (Figure 22). Chironomidae were numerically the most abundant taxon followed by Oligochaeta in June, July,

and August of 2005 (Figure 22).

Sturgeon Diet:

Diet samples taken in June, July and August from a subsample of the fish captured (N=120). Stomach contents consisted of 98.6 % Chironomidae. The other 1.4% consisted of a diverse array of macroinvertebrates and fish (Figure 23). Whole Chironomidae were over- represented in the diet compared to their availability. Oligochaeta were clearly under- represented in the diet (Figure 22). This may indicate a positive selection (preference) for Chironomidae and negative selection (avoidance) for Oligochaeta. However the absence of Oligochaeta in juvenile lake sturgeon diets may also be due to the potentially rapid digestion rate of this taxa, coupled with the 24-hour duration of the gill net sets, which likely allowed considerable digestion to occur.

Genesee River Sturgeon Stomach Contents 2005 Excluding Chironomidae Fish Simulidae Arachnida Tipulidae 0.06% Glossosomatidae 0.03 Diptera Emergent 0.01% 0.01% 0.01% 0.01% Hydropsychidae 0.06% Baetidae Corydalidae 0.11% 0.01% Ostracoda 0.01% Ephemerellidae 0.15%

Copepoda 0.46% Heptagenidae 0.01%

Daphnia 0.14% Elmidae Corixidae 0.01% Amphipoda 0.28% 0.05%

Figure 23. Diversity represented in the juvenile sturgeon diet.

Fish were only found in the stomachs of two sturgeon in August, 2005. The largest sturgeon caught was 543 mm and 790 g and when the stomach was pumped it contained fish parts and chironomids.

Size and Growth of Juvenile Sturgeon in the Genesee River.

One good measure of the success of any introduction experiment is measurement of the growth rate of the stocked fish. The 03 YC fish grew an average of 130 mm and gained an average of 138 g during the growing season of 2004 (Table 9).

Table 9. Average length and weight and range of lengths of the 03YC fish from stocking to October 2004. Average Length Average Weight N Length Length Month mm g Smallest Largest Sept 03 210 43.6 100 100 255 0ctober 03 236 52.75 4 220 250 May 04 244.5 57.0 2 224 265 June 04 273.4 74.8 5 262 289 July 04 294.6 90.9 15 271 320 August 04 328.7 137.0 60 265 384 September 04 347.4 162.4 9 284 408 October 04 374.2 194.9 52 290 445

The average 03YC sturgeon grew 50 mm and gained 145 g from May 2005 to August 2005. (Table 10). The smallest fish caught in August was 347 mm and 135 g. The average 04YC sturgeon grew 128.9 mm and gained 89.6 g in the 11 months from stocking in September of 2004 to August 2005 (Table 11).

Table 10. Average length and weight and range of lengths of the 03YC fish from May 2005 to August 2005. Average Length Average Weight N Length Length Month mm g Smallest Largest May 05 387.4 243.7 22 309 432 June 05 400.1 268.1 29 320 471 July 05 425.0 324.3 76 339 504 August 05 437.1 339.1 48 347 542

Table 11. Average length and weight and range of lengths of the 04YC fish from stocking to August 2005. Average Length Average Weight N Length Length Month mm g Smallest Largest Sept. 04 169.1 23.4 100 104 220 October 04 217 35.3 6 190 243 May 05 242.7 61.9 9 196 276 June 05 263.6 79.4 21 209 303 July 05 281.3 94.3 108 225 345 August 05 298.0 113.0 89 239 413

The average size of the 03YC stocked fish was larger than the 04YC stocked fish partly due to between year variation at the hatchery and partly due to some size selection when allocating fish to the Genesee in 2003. To compare the growth rates of the 2003 and 2004 stocked fish we contrast the growth between May and August in the 1st year after stocking. The 03YC fish grew 84 mm and gained 80 g from May 2004 to August 2004. The 04 YC fish grew 55 mm and gained 51 g over the associated time period (Table 11). There is very little data in the literature on the overall growth patterns of age 0 and age 1 sturgeon. By examining the change in size distribution over time we can see how the size of the general sturgeon populations changes with time.

Genesee Stocked Sturgeon 03YC

80.0 70.0 y = 5.2021x - 65.495 2 60.0 R = 0.8959 50.0 40.0 30.0

Weight (g) Weight 20.0 10.0 0.0 8.010.012.014.016.018.020.022.024.026.028.0 Length (cm)

Figure 24. Size distribution of 03YC at stocking in September. Green dots represent the size of fish caught in October 2003.

There was a significant linear relationship between total length and weight (R2 =0.896, Zar 1984).

Genesee River Stocked Sturgeon 04YC

80 70 60 y = 0.3685x - 38.869 2 50 R = 0.9386 40 30 Weight (g) Weight 20 10 0 80 105 130 155 180 205 230 255 280

Total Length (mm)

Figure 25. Size distribution of 04YC at stocking in September. Green dots represent the size of fish caught in October 2004.

Representative Monthly Size Distributions of 03YC in 2004 May 350 June August August 300 y = 1.3081x - 293.05 2 October 250 R = 0.8481 Linear (August) 200 Linear (October) 150 October

Weight (g) y = 1.622x - 412.46 100 R2 = 0.9258 50 0 200 250 300 350 400 450 500 Length(mm)

Figure 26. Change in the size distribution of the 03YC sturgeon in 2004

Size Distribution of 03YC in 2005

800

600 May

) y = 1.9299x - 503.93 May R2 = 0.9175 August 400 Linear (May)

Weight (g August Linear (August) 200 y = 2.6549x - 821.54 R2 = 0.8957

0 300 350 400 450 500 550 600 Lenght (mm)

Figure 27. Change in the size distribution of 03YC in 2005. 42

Size Distribution of 04YC in 2005

250

200 May May ) y = 0.7196x - 112.81 August 150 R2 = 0.9499 Linear (May) 100 Linear (August) Weight (g August 50 y = 1.1253x - 227.77 R2 = 0.9382 0 150 200 250 300 350 400 450 Length (mm)

Figure 28. Change in size distribution of 04YC fish in 2005.

As of August of 2005 the relationship of weight and length was still best described by a linear relationship (R2=0.9382), Zar 1984)

Growth of 03YC Aug. 04 to July 05

41 600 42 500 45 400 52 300 54 200 58 Weight (g) 61 100 64 0 72 250 300 350 400 450 500 550 81 Length (mm) 104

Figure 29. Growth of individuals captured in August 2004 and recaptured July of 2005. Numbers are the tag numbers of the individual fish. 43

Recapture data provided information on the growth patterns of individuals. One example is given in figure 29. All of the individuals of the 03YC showed similar growth trajectories from August 2004 to July 2005. As of August 2005, the relationship of weight and length was still best described by a linear relationship (Figure 27). Details of the data on growth patterns of all recaptured individuals will be available in a data archive.

DISCUSSION

The first two years of examining stocking as a sturgeon rehabilitation strategy has been highly successful. The basic hypothesis tested in this experiment was that the Genesee River contains habitats that stocked juvenile sturgeon would find suitable as nursery habitat. Total habitat available in the lower Genesee for foraging is 9.3 km long with an area of 256 ha, which constitutes a fairly small system. This area was rated as good foraging habitat using a sturgeon habitat suitability index (Threader et al. 1998, Dittman 2006). The stocked sturgeon stayed in the target habitat of the lower 9 rkm of the Genesee River in high numbers, 43.5% of the 03YC and 68% of the 04YC were in this section of the river as of August 2005, when the second stage of this experimental test ended. Most captures were in the deepest sections of the given river reach. Nets set in shallower locations produced very few sturgeon, but did catch larger numbers of redhorse suckers and walleye. The observation of congregations of very young sturgeon is consistent with some reports from other systems (Chiasson et al. 1997, Hayes and Warner 2004, Benson et al. 2005, Smith & King 2005). Although, the numbers reported here are much higher than in any other study. The habitat in which the fish were captured was gravely to sandy except at the lowest silty site in the river. This lowest part of the river is in a dredged area and is consistent with observed sturgeon use of dredged areas (Schram et al 1999). In the hatchery, juvenile sturgeon show a preference for sandy substrate (Peake 1999). Evaluation of HSI predictions to juvenile lake sturgeon capture sites in the Genesee River resulted in agreement, (Threader et al. 1998). Foraging habitat HSI variables include silt and sand as the optimal substrates and benthic production of macroinvertebrates, optimal water velocities between 10 and 40 cm /sec, and depths between 1 and 7 meters. These variables match the habitat attributes in this target area of the Genesee River. 44

Growth for the year classes was similar to other systems (Schlueter 2000, Jackson et al. 2002, Holtgren and Auer 2004). Juvenile sturgeon diet consisted primarily of Chironomidae, which is similar to diets in other systems (Choudhury et al.1996, Kempinger 1996, Chiasson et al. 1997) Post stocking assessment is a critical component of management using hatcheries as a tool (Wiley 1999). The results of this research show that the released juvenile lake sturgeon survive in the Genesee River and are successfully using the available river habitat as nursery habitat in a manner consistent with the habitat suitability predictions done before stocking (Dittman 2006). Measurement of post-stocking river retention, growth, and habitat use by hatchery reared fish has provided valuable information for assessment of this management tool and habitat suitability for juvenile sturgeon in this river. The Genesee River is thus considered by the NYS Department of Environmental Conservation to be an excellent candidate for restoration to a self-sustaining lake sturgeon population through stocking (Keeler 2005). The initial success of sturgeon in the Genesee provides a start toward meeting the sturgeon based de-listing criteria for the Rochester Area of Concern. Possible next research steps in the Genesee could involve radio or sonic tagging for tracking juvenile movements and habitat use. There are two questions that could be investigated. The first would involve short term (diel cycles, up to one month intensive) to determine diel movements, and possible identification of microhabitat use not detected by gill net surveys (Smith and King 2005). The second could involve longer term tracking of seasonal movements of older fish in the river and into the shallow areas of Lake Ontario (Hughes et al. 2005).

Long Term Research and Monitoring

This study was designed as an evaluation of current Genesee River fish habitat that focused on an experimental stocking strategy to assess juvenile habitat use and the practicality of juvenile sturgeon stocking as a method of adaptive sturgeon management in this river, and was not planned as an initiation of a long term sturgeon restoration project. However, as long as stocked lake sturgeon remain in the Genesee River, some monitoring will continue to determine their continuing and changing utilization of this river. Long term study is needed to determine full restoration potential and role of hatcheries. 45

There are many additional challenges in restoring such a large long lived species (Auer 1999, Musick 1999). One to be considered is that the timeframe for restoration is likely longer than the research career of the individual scientists. We are optimistic that supplemental and continuing research on the Genesee River fish and fish habitat will occur. Although it is uncertain to predict years into the future, hopefully the partnering entities will be able to continue sampling for sturgeon, perhaps focusing on male sturgeon likely to be entering the river to spawn by 2013 and the females possibly entering soon after that, 2015 to 2018.

Acknowledgements:

Thanks for invaluable assistance with field work, laboratory work, analysis, and project support go to D. Carlson, M. Chalupnicki, K. Douglas, C. Ewell-Hodkin, M. Goehle, S. Hanna, T. Hughes, C. Lowie, A. McCarthy, R. McDonald, B. Nelson, I. Palmer, P. Randall, B. Trometer, T. Wallbridge, M. Weimer, USFWS and USGS summer personnel, W. Pearsall and NYSDEC field and hatchery personnel. This project was partially funded by the USEPA- GLNPO, the NYSDEC, the USGS, and the USFWS and was a successful multi-agency cooperative project.

References:

Auer, N.A. 1999. Lake Sturgeon: A Unique and Imperiled Species in the Great Lakes. pp: 515- 538 Great Lakes Fisheries Policy and Management A Binational Perspective. Michigan State University Press. East Lansing Michigan. Auer, N.A. 2003. A lake sturgeon rehabilitation plan for Lake Superior. Great Lakes Fish. Comm. Misc. Publ. 2003-02. Bain, M.B. and N. J. Stevenson. (Eds.) 1999. Aquatic Habitat Assessment, Common Methods. American Fisheries Society, Bethesda, Maryland. Beamesderfer, R. C. P. and R. A. Farr. 1997. Alternatives for the protection and restoration of sturgeons and their habitat. Environmental Biology of Fishes. 48:407-417. Bearlin, A. R., E.S.G. Schreiber, S. J. Nicol, A. M. Starfield, and C. R. Todd. 2002. Identifying the weakest link: simulating adaptive management of the reintroduction of a threatened fish. Can. J. Fish. Aquat. Sci. 59:1709-1716. Bemis, W.E. and B. Kynard. 2002. Sturgeon rivers: an introduction to Acipenseriform biogeography and life history. Env. Biol. Fish. 48:167-183. Beamish, F. W., J. Jebbink, A. Rossiter and D. L. G. Noakes. 1996. Growth strategy of juvenile lake sturgeon (Acipenser fulvescens) in a northern river. Can. J. Fish. Aquat. Sci. 53:481- 489. Benson, A.C., Sutton, T.M., Elliott, R.F., and Meronek, T.G. 2005. Seasonal movement patterns 46

and habitat preferences of age-0 lake sturgeon in the lower Peshtigo River, Wisconsin. Trans. of the Amer. Fish, Soc. 134:1400-1409. Birstein, V. J., W. E. Bemis and J. R. Waldman. 1997. The threatened status of Acipenseriform species: a summary. Env. Biol. Fish. 48: 427-435. Black, S.R., 1944. Seth Green Father of Fish Culture. Rochester History, vol. VI, No.3 Bouton, D. 1994. A recovery plan for the Lake Sturgeon (Acipenser fulvescens) in New York. NYSDEC Brosse, L., P. Dumont, M. Lepage, and E. Rochard. 2002. Evaluation of a gastric lavage method for sturgeons. North American Journal of Fisheries Management. 22:955-960. Busch, W.D.N. and S.J. Lary. 1996. Assessment of habitat impairments impacting the aquatic resources of Lake Ontario. Can. J. Fish. Aquat. Sci. 53:113-120. Carlson, D.M 1995. Lake sturgeon waters and fisheries in New York State. J. Great Lakes Res. 21:35-41. Carlson, D.M. 2000. A recovery plan for the Lake Sturgeon (Acipenser fulvescens) in New York. NYSDEC. Updated Carlson, D.M. 2005. The second ten-years of planning for extensive management of lake sturgeon (Acipenser fulvescens) in New York. Bureau of Fishes, Endangered Fish Project Chiasson, W.B., D.L.G. Noakes, and F.W.H. Beamish. 1997. Habitat, benthic prey, and distribution of juvenile lake sturgeon (Acipenser fulvescens) in northern Ontario rivers. Can. J. Fish. Aquat. Sci. 54:2866-2871. Choudhury, A., R. Bruch, and T.A. Dick. 1996. Helminths and food habits of Lake Sturgeon Acipenser fulvescens from the Lake Winnebago system, Wisconsin. Am. Midl. Nat. 135:274-282. Clune, H.W. 1963. The Genesee. pp. 227-234. Rivers of America. Holt Rinehart and Winston. New York Dittman, D.E. 2006. Suitability of the lower Genesee River, New York, for Lake Sturgeon (Acipenser fulvescens). Journal of Freshwater Ecology. Accepted Elliott, R.S. 1997. Monroe County Environmental Report Card. Division of Environmental Health, Monroe County Department of Health. Rochester NY. Galarowicz, T. 2003. Conservation Assessment for Lake Sturgeon (Acipenser fulvescens). USDA Forest Service, Eastern Region. 1-24. Gardmark, A., K. Enberg, J. Ripa, J. Laakso, and V. Kaitala. 2003. The ecology of recovery. Ann. Zool. Fennici. 40:131-144. Greeley, J.R. 1927. Fishes of the Genesee region with annotated list. In: A biological survey of the Genesee River system. : 47-66. Supplement to the 16th Annual Report of the New York Conservation Dept, Albany Gerrity, P. C. 2005. Habitat use, diet, and growth of hatchery-reared juvenile pallid sturgeon and indigenous shovelnose sturgeon in the Missouri River above Fort Peck Reservoir. Masters of Science Thesis. Montana State University. 1-62. Grogan, C.S. and J. Boreman 1998. Estimating the probability that historical populations of fish species are extirpated. North Amer. J. Fish. Man. 18:522-529. Gross, M. R., J. Repka, C. T. Robertson, D. H. Secor and W. Van Winkle. 2002. Sturgeon conservation: insights from elasticity analysis. Amer. Fish. Soc. Symposium. 28: 13-30. Harkness, W.J.K., and J.R. Dymond. 1961. The lake sturgeon. The history of its fishery and problems of conservation. Ont. Dept. Lands and Forests, Fish and Wildl. Br. 121 pp. 47

Hay-Chmielewski, E.M. and G.E. Whelan (eds). 1997. Lake Sturgeon Rehabilitation Strategy. Michigan Department of Natural Resources. Fisheries Division Special Report 18. Hayes, J. and Werner, R.G, 2004. Contributing Factors in Habitat Selection by Lake Sturgeon (Acipenser fulvescens). United States Environmental Protection Agency- Great Lakes National Program Office. Final Report, pp. 1-24 Hess, G.R., 1996. Linking Extinction to Connectivity and Habitat Destruction in Metapopulation Models., The American Naturalist, Vol.148, No.1, pp. 226-236 Hickey, M. B. C. 2003. Status of Lake Sturgeon (Acipenser fulvescens) in the Cornwall Area of Concern. Report Prepared for Environment Canada, Restoration Programs Division, and The St. Lawrence River (Cornwall) Remedial Action Plan. 30pp. Holey, M., E. Baker, T. Thuemler, and R. Elliot. 2000. Research and assessment needs to restore lake sturgeon in the Great Lakes. Great Lakes Fishery Trust Lansing MI 37p Holtgren, J. M. and N. A. Auer. 2004. Movement and habitat of juvenile lake sturgeon (Acipenser fulvescens) in the sturgeon river/portage lake system, Michigan. Journal of Freshwater Ecology. 19(3):419-432. Hughes, T. C., C. E. Lowie and J. M. Haynes. 2005 Age, Growth, Relative Abundance, and SCUBA Capture of a New or Recovering Spawning Population on Lake Sturgeon in the Lower Niagara River, New York. North Amer. J. Fish. Man. 25:1263-1272. Ireland, S. C., P. J. Anders, and J. T. Siple. 2002. Conservation Aquaculture: an adaptive approach to prevent extinction of an endangered white sturgeon population. Am. Fish. Soc. Sym. 28:211-222. Jackson, J.R., A.J. Van DeValk, T.E. Brooking, O.A. Van Keeken, and L.G. Rudstam. 2002 Growth and feeding dynamics of lake sturgeon, Acipenser fulvescens, in Oneida Lake, New York: Results from the first 5 years of a restoration program. Journal of Applied Ichthyology 18:439-443. Keeler, S. 2005. Comprehensive Wildlife Conservations Strategy Species Group Reports for Freshwater Fish: Lake Sturgeon: 53-58. NYSDEC Kelso, J.R., R.J. Steedman, and S. Stoddart. 1995. Historical causes of change in Great Lakes fish stocks and the implication for ecosystem rehabilitation. Can. J. Fish. Aquat. Sci. 53 (Suppl. 1):10-19. Kempinger, J. J. 1996. Habitat, growth, and food of young lake sturgeons in the Lake Winnebago System, Wisconsin. North Am. J. Fish. Man. 16 (1): 102-114. Klindt, R. M. 2005. Lake Sturgeon Egg Take Manual. NYS Department of Environmental Conservation 19pp Watertown NY. Lowie, C.E., T. C. Hughes, and S.L. Schlueter. 2000. Great Lakes Native Fish Restoration: Lake Sturgeon, Final Progress Report. Administrative Report 2000-01, USFWS, Lower Great Lakes Fishery Resources Office, Amherst, NY. 15pp. Moulton, S.R., J. L. Carter, S. A. Grotheer, T. F. Cuffney, and T. M. Short. 2000. Methods of analysis by the U.S. Geological survey national water quality laboratory - processing, taxonomy, and quality control of benthic macroinvertebrate samples. U.S. Geological Survey Open-File Report. 00-212. Musick, J.A., 1999. Ecology and Conservation of Long-Lived Marine Animals. American Fisheries Society Symposium, 23:1-10. Nilo, P., P. Dumont, and R. Fortin. 1996. Climatic and hydrological determinants of year-class strength of St. Lawrence River lake sturgeon (Acipenser fulvescens). Can. J. Fish. Aquat. 48

Sci. 54:774-780. NYSDEC 2004. New York State Water Quality 2004. : A31-A40 Peake, S., 1999. Substrate preferences of juvenile hatchery-reared sturgeon lake sturgeon, Acipenser fulvescens. Environmental Biology of Fishes. 56:367-374. Peckarsky, B.L., P.R. Fraissinet, M.A. Penton, and D.J. Conklin, Jr. 1990. Freshwater macroinvertebrates of northeastern North America. Cornell University Press. Ithaca. NY Pikitch, E.K., Doukakis, P., Lauck, L., Chakrabarty, P., and Erickson, D.L., 2005. Status, trends and management of sturgeon and paddlefish fisheries. Fish and Fisheries, 6, 233-265. Pine, W.E., K.H. Pollock, J.E. Hightower, T.J. Kwak, and J.A. Rice. 2003. A review of tagging methods for estimating fish population size and components of mortality. Fisheries. 28:10-23. Schlueter, S. 2000. Oswegatchie river Lake Sturgeon restoration project. In: Brookings, T.E. Update on Lake Sturgeon in New York Waters. Cornell, Ithaca NY. Schram, S.T., J. Lindgren, and L.M. Evrard. 1999. Re-introduction of lake sturgeon in the St. Louis River, western Lake Superior. North Amer. J. Fish. Man.19:815-823. Secor, D. H., P. J. Anders, W. Van Winkle and D. A. Dixon. 2002. Can we study sturgeons to extinction? What we do and don’t know about the conservation of North American sturgeons. American Fisheries Society Symposium. 28:3-10. Secor, D. H., Niklitschek, E.J., Stevenson, J.T., Gunderson, T.E., Minkkinen, S.P., Richardson, B., Florence, B., Mangold, M., Skjeveland, J., Henderson-Arzapalo, A., 2000. Dispersal and growth of yearling Atlantic sturgeon, Acipenser oxyrinchus, released into Chesapeake Bay. Fish Bull. 98:800-810. Sherwood, D.A., 2003. Water Resources of Monroe County, New York, Water Years 1997-99, with Emphasis on Water Quality in the Irondequoit Creek Basin, Atmospheric Deposition, round Water, Stream flow, Trends in Water Quality, and Chemical Loads to Irondequoit Bay. USGS Water- Resources Investigations Report 02-4221 Smith, K. M. and D. K. King. 2005. Movement and Habitat use of Yearling and Juvenile Lake Sturgeon in Black Lake, Michigan. Trans. Amer. Fish. Soc. 134:1159-1172. Stewart, T.J., R.E. Lang, S.D. Orsatti, C.P. Schneider, A. Mathers, and M.E. Daniels. 1999 Fish community objectives for Lake Ontario. Great Lakes Fish Comm. Spec. Pub. 99-1 56p. Threader, R.W., R. J. Pope, and P.R.H. Schaap. 1998. Development of a habitat suitability index model for lake sturgeon (Acipenser fulvescens). Ontario Hydro Report No. H- 07015.01--0012 USEPA 2002. Lake Ontario LaMP 2002 Report. Welsh, A. 2004. Factors influencing the effectiveness of local versus national protection of migratory species: a case study of lake sturgeon in the Great Lakes, North America. Environmental Science and Policy. 7:315-328. Wentworth C.K. 1922. A scale of grade and class terms for clastic sediments. Journal of Geology 30:377-392. Wiley, R.W. 1999. Fish hatcheries are a powerful tool of fisheries management. Fisheries 24(9): 24-26. Young, K.A., 1999. Managing the decline of Pacific salmon: metapopulation theory and artificial recolonization as ecological mitigation. Can. J. Fish. Aquat. Sci. 56: 1700-1706. Zar J.H. 1984. Biostatistical analysis. 24th edition. Chapter 17. Simple linear regression. Prentice Hall Englewood Cliffs, NY. 49