Lake sturgeon image

GREAT LAKES NATIVE FISH RESTORATION:
LAKE STURGEON

FY1997 Fisheries Stewardship Proposal

FINAL PROGRESS REPORT
Map of the Great Lakes showing Lake Ontario

REGION 5 – HADLEY, MASSACHUSETTS
Field Station – Lower Great Lakes Fishery Resources Office Amherst, NY
Lake Sturgeon Program Coordinator: Christopher Lowie
Lake Sturgeon Biological Technicians: Thomas Hughes and Scott Schlueter

MARCH 2000


ACKNOWLEDGEMENTS

We would like to extend great gratitude to John Whiteman, a member of the Niagara River Anglers Association and riparian landowner, for granting permission to process captured lake sturgeon at his property. We want to thank the Niagara County Fisheries Advisory Board (NY) for providing funding for the Great Lakes Sturgeon video filming and New York Power Authority for providing sonic tags for the study. A special thanks to volunteers Dave Tosetto and Seth Raby for their SCUBA diving assistance with filming and field sampling. Finally, thanks to all LGLFRO staff and volunteers for their assistance on this project.

 


TABLE OF CONTENTS

BACKGROUND
   
Purpose

INTERAGENCY COORDINATION
   
Genetic Workshop Minutes
   
Information Needs
   
Collection, Fixing, and Preservation Methods
   
Centralized Depository for Samples
   
Analysis Methods
   
Funding

EVALUATION OF POPULATION CHARACTERISTICS AND HABITAT ASSESSMENT
    Lower Niagara River

    Ultrasonic Biotelemetry

    Genesee River

HATCHERY SUPPORT
    Oswegatchie River

LAKE STURGEON SIGHTING PROGRAM and PUBLIC EDUCATION

DISCUSSION
   
Plans for 2000

REFERENCES


BACKGROUND
The lake sturgeon, Acipenser fulvescens, is the only sturgeon endemic to the lower Great Lakes and is the largest of all fish species in the basin. Lake sturgeon mature at 15-20 years of age, spawn only periodically, and may survive to 100-150 years. Early commercial fishermen (pre-1850) perceived lake sturgeon as a nuisance fish because of fishing gear destruction. Later recognized for its commercial value, a targeted fishery for lake sturgeon intensified. The lake sturgeon fishery finally collapsed by 1920 due to environmental changes and the lake sturgeon’s slow growth, late maturity, and infrequent spawning. From 1900 to the 1970s, little was known about the lake sturgeon population, except for its continued decline. Environmental factors affecting the decline include damming of tributaries preventing access to historical spawning grounds, destruction of spawning areas via siltation from deforestation, agriculture, and dredging, and pollution from nutrient and contaminant loads. Only a remnant population remains today, causing the lake sturgeon to be listed as threatened by New York State and the American Fisheries Society and as endangered by Pennsylvania and Ohio.

The role of the Fish and Wildlife Service in restoring native Great Lakes fish stocks as part of ecosystem rehabilitation has become more clearly defined over the past five years, and continues to expand. The major causes of the demise of native fish are being addressed through various regulatory and management initiatives, with active cooperation of many agencies. This has set the stage for major progress in the restoration and rehabilitation of native fish species. With success stories of lake whitefish, lake trout, and burbot in all the Great Lakes, the opportunities for lake sturgeon rehabilitation has never been greater.

Interest in the restoration of lake sturgeon by Great Lakes scientists has increased greatly. The fish provides an unequaled symbol of ecosystem health and biodiversity. Restoration of this fish and its habitat is in keeping with the Service's "Fisheries’ Vision for the Future" and the "Fisheries Action Plan" which focus on interjurisdictional, native and depleted species and related ecosystem impairments. This stewardship project focuses on ecosystem and resource management and conservation through habitat protection and restoration.

The Framework for the Management and Conservation of Paddlefish and Sturgeon Species in the United States (Booker et al. 1993) reaffirms the Service's commitment to restoring these particular species. Throughout this document, the Service is referenced as a partner and a national leader in the ecosystem management and conservation of sturgeon species. Problems identified in the Framework Plan are being addressed in this Stewardship Project.

In addition, the activities presented in this report support several recommendations stated in the "Great Lakes Fishery Resources Restoration Study" (USFWS 1995) and the Service’s "Great Lakes Ecosystem Resource Goals and Objectives" (#1,2,4,6, and 7). This project also assists the New York State Department of Environmental Conservation in their protection and restoration efforts outlined in "A Recovery Plan for Lake Sturgeon in New York" (Carlson 1999).

The Lower Great Lakes Fishery Resources Office’s (LGLFRO) Lake Sturgeon Program continues to work on activities associated with the five components previously established in the Stewardship Proposal. These components include: (1) coordination of interjurisdictional activities; (2) evaluation of population characteristics and discreteness of remnant stocks; (3) assessment of habitat and rehabilitation requirements; (4) hatchery support technologies and brood stock maintenance; and, (5) public education. Projects which encompass all components were initiated in 1998 (Lowie et al 1998, 1999). Previous activities were continued and expanded in FY99. The stewardship funding allowed us to maintain two fishery technicians, and expand on our previous work in order to achieve project objectives.

Purpose

The purpose of this document is to report the progress of ongoing research efforts implemented under the final year of the 1997 Stewardship Funds. This document provides information regarding the Lower Great Lakes Fishery Resources Office’s Lake Sturgeon Program activities conducted during federal fiscal years 1999 and early 2000.

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INTERAGENCY COORDINATION

The LGLFRO plays a critical role in the interagency coordination of lake sturgeon rehabilitation efforts in the lower Great Lakes watershed. We remain as a member of two interagency lake sturgeon workgroups; St. Lawrence River and the Central Great Lakes Bi-National Lake Sturgeon Workgroup, in addition to providing professional and technical assistance to the New York Department of Environmental Conservation.

Through the USFWS, R5-R3 Great Lakes Basin Ecosystem Team’s (Ecoteam) Lake Sturgeon Committee, the LGLFRO has taken a leadership role in trying to coordinate and standardize lake sturgeon genetics activities in the Great Lakes Basin. The document entitled, Great Lakes Lake Sturgeon Genetics Status Assessment: An Analysis of Samples, Methods, and Standardization (Lowie 1999) has been completed. In addition, we hosted a Great Lakes Lake Sturgeon Genetics Workshop on December 8-9, 1999 in Chicago, IL. The workshop provided a forum for biologists, managers, and geneticists to discuss the current state-of-knowledge, identify information needs, and standardize further collection and analysis of genetic samples. The minutes from the workshop have been completed and distributed to participants and Ecoteam, Lake Sturgeon Committee members. A brief overview from the open discussion session is provided below; however, these minutes have not been critically reviewed. The information is being provided for planning purposes only and should not be referenced. A proceedings document will be available in the near future, which will include final recommendations for future sample collection, distribution, and analysis. As a result of the workshop, the LGLFRO is leading the effort to develop and submit funding proposals for future research. The LGLFRO was recently assigned Chair of the Ecoteam’s Lake Sturgeon Committee.

Genetic Workshop Minutes

Information Needs

The following are needs identified by participants:

Collection, fixing, and preservation methods

Samples should be collected primarily from spawning populations; however, samples from open water fish are valuable. Fin tissue is the most effective, yet least invasive tissue type and should be provided in most circumstances. Use your best professional judgement as to the quantity of tissue collected; however, more is better (up to 1 square inch from adults). Water rinse and wipe hands and utensils between samples to ensure they are not contaminated. The best fixing and preservation method was determined by geneticists to be air-drying. Drying is most easily achieved by placing the sample in a paper envelope. However, this is not best for archiving samples due to possible pest infestation. The second best method for preservation is putting the sample in 95% alcohol (not denatured alcohol), particularly if archiving the sample. It is best to change the alcohol after the initial fixation for long term storage. Completely submerge sample in at least two times as much alcohol as sample. If samples are frozen, keep them frozen until analysis is being conducted.

Centralized depository for samples

It was discussed whether a depository should be established for samples or data. It was determined a database would be acceptable, which would be available to Great Lakes agencies. The database will be held within the USFWS Great Lakes Basin Ecosystem Team, Lake Sturgeon Committee’s standardized database (to be held at the Alpena, MI FRO). This database will include information on standard biological data, tagging data, collector, location, etc.

Analysis methods

Microsatellite analysis is fastest for stock identification; however, experimentation with other methods will be left open for the future. A library of microsatellite markers is being established between some cooperative labs. More microsatellite markers might be needed; however, all existing markers should be examined more thoroughly to evaluate their usefulness. Existing and additional markers should be standardized and available to allow multiple labs to compare data. Contracts between agencies and genetic labs should be specific as to the use of samples and data.

Funding

There is potential to receive funding for a Great Lakes-wide study through the Great Lakes Fishery Trust (funded this workshop) or the Great Lakes Fishery Commission via dollars from reauthorization of the USFWS-Great Lakes Fish and Wildlife Restoration Act. After the workshop, EPA’s Great Lakes National Program Office (GLNPO) was identified as another source. Regardless of funding sources, this needs to be a collaborate effort among and between natural resource agencies and geneticists. It was decided Chris Lowie would develop two proposals, in cooperation with participants. One would be to request dollars for standardizing markers and the other for collecting samples from spawning populations throughout the basin, including areas where no samples are currently available.

The LGLFRO continues to lead the effort to obtain funding for genetics analysis. Proposals have been submitted to three sources, requesting funding over four years to collect additional samples from spawning populations, develop new markers, standardize the markers, perform stock structure analysis, and prepare a basin-wide management plan. To facilitate this study, it is recommended to continue collecting genetics samples and to hold them for later analysis. However, if there is an immediate need to have them analyzed, a contractual agreement should first be established.

The LGLFRO assisted the Shackleton Point Warmwater Research Station (Cornell University) with organizing a small workshop to update management agencies on lake sturgeon research in New York State, primarily the Lake Ontario/St. Lawrence River Watershed. This became an expansion of the St. Lawrence River ad-hoc group. Various researchers gave a brief overview of their activities and discussed ways to collaborate in the future. A Meeting Summary is available from the Shackleton Field Station.

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EVALUATION OF POPULATION CHARACTERISTICS AND HABITAT ASSESSMENT

Lower Niagara River

Since the summer of 1998, we have been studying the population of lake sturgeon in the lower Niagara River. This lake sturgeon project is in cooperation with the State University of New York - College at Brockport. The data provided here is considered preliminary results, with complete analysis of the data being provided via a thesis publication (Hughes et al. manuscript in progress).

The overall goal of our study is to identify key spawning and feeding habitats in the river in order to better manage, protect, and enhance the lake sturgeon population. The research objectives of our study are to: (1) compare the daily, seasonal, and diel movement patterns of juvenile and adult lake sturgeon, (2) compare the utilization of macro- (e.g., river, main lake) and micro- (e.g., high flow, back eddy) habitats between juvenile and adult lake sturgeon, (3) determine the age and growth of adult and juvenile lake sturgeon, and (4) determine the genetic discreteness of Niagara River lake sturgeon.

Biologists holding a lake sturgeonTo date, we have collected 32 lake sturgeon by SCUBA diving, gill nets and baited setlines. In 1999, we captured a total of 26 sturgeon with a CPUE of 0.27 fish per night for all methods (Table 1). We began our 1999 gillnetting efforts in late April by targeting adult fish (> 1200 mm) with 10" stretch mesh gillnets. We successfully captured five suspected adult fish (two known ripe males) before increased algal and macrophyte drift decreased our sampling efficiency. We continued to sample through the summer; however, no additional adult sturgeon were captured. During the months of September and October, we had tremendous success using setlines baited with Chinook salmon egg skein, with a CPUE of 0.58 fish per night. We believe the sturgeon were keying in on the salmon eggs as large numbers of salmon were migrating up the river for their annual fall spawning run. Additionally in 1999, a considerable number of anglers reported catching lake sturgeon while salmon fishing.

Not knowing the age at maturity of the Niagara River population, we feel we have been catching primarily juvenile (<1000 mm TL) and sub-adult (1000-1200 mm TL) fish, with at least five fish, based on length, likely to be adults (>1200 mm TL) (Table 2). Two fish were known to be ripe adults since milt was observed during processing. We were unsuccessful, via internal examination through incision, in determining the sex and maturity of the other adult-sized fish.

Table 1. Comparison of lake sturgeon catch among different gear types in lower Niagara River, 1999.

 

Gear Type

 

Exp. Gill Net

10" Gill Net

Setline

Diver

All

No. Fish Captured

3

7

10

6

26

CPUE (fish/night)

0.33

0.13

0.42

3.0

0.27

Mean Total Length (mm)

874

1254

990

766

996

Range (mm)

705 - 1141

886 –1566

851 - 1186

311 - 1021

311 – 1566

Mean Weight (kg)

5.4

17.6

6.4

3.1

8.5

Range (kg)

1.8 – 11.8

4.3 – 33.9

3.0 – 15.0

0.2 – 6.3

1.8 – 33.9

 

Pectoral fin rays were collected and analyzed to interpret the ages of all lake sturgeon captured. Ages of lake sturgeon captured ranged from 1 to 20 years old, with a majority (n =19) of fish between 4 to 6 years old (Figure 1, Table 2). Suspected adult fish were determined to be between the ages of 12 and 20 years old. Both of the ripe males were 12-year-old fish. In addition, two fish categorized as sub-adults (based on total length) were determined to be 12 years old and could potentially be adult fish (Table 2). The growth of these fish appear to be higher than populations from the Lake Huron Basin (Hill and McClain 1999). Specifically, lake sturgeon from the Niagara River tend to be longer and heavier than lake sturgeon of the same age from Lake Huron waters (Hill and McClain 1999). Age-length relationship is shown in Figure 2.

 

Figure 1. Age distribution of lake sturgeon caught in the lower Niagara River, 1998-99.

Figure 1. Age distribution of lake sturgeon caught in the lower Niagara River, 1998-99.

 

Table 2. Biological data for lake sturgeon captured in lower Niagara River, 1998-99.

Date Capture

Fork Length (mm)

Total Length (mm)

Girth (mm)

Weight (kg)

Age (yrs)

Suspected Maturity*

8/1/98

289

337

125

N/A

1

Juvenile

8/1/98

624

705

306

2

3

Juvenile

8/12/98

755

854

368

4

5

Juvenile

8/14/98

860

966

371

5.2

6

Juvenile

8/14/98

741

847

343

3.3

5

Juvenile

8/26/98

778

866

345

3.6

5

Juvenile

8/28/98

639

725

272

1.6

4

Juvenile

4/27/99

1197

1314

578

19.5

16

Adult

4/28/99

777

886

375

4.3

6

Juvenile

4/28/99

1396

1435

655

25.2

18

Adult

4/28/99

1450

1566

720

33.9

20

Adult

5/5/99

1121

1256

534

14.5

12

Ripe Adult (male)

5/18/99

1155

1240

260

15.5

12

Ripe Adult (male)

6/3/99

899

1021

414

6.3

8

Sub-adult

6/3/99

272

311

122

0.15

1

Juvenile

7/16/99

768

872

317

3

5

Juvenile

7/23/99

1020

1141

502

11.8

9

Sub-adult

7/23/99

788

890

359

4.2

6

Juvenile

7/23/99

746

837

319

3.2

5

Juvenile

7/23/99

690

787

310

2.7

5

Juvenile

7/23/99

668

750

297

2.2

5

Juvenile

7/30/99

658

705

265

1.8

3

Juvenile

8/4/99

695

775

295

2.6

5

Juvenile

8/6/99

976

1078

461

10

12

Sub-adult

8/6/99

968

1081

443

9.1

10

Sub-adult

8/19/99

755

851

355

3.7

6

Juvenile

9/29/99

818

940

410

4.8

5

Juvenile

9/29/99

854

963

328

4.2

6

Juvenile

9/29/99

898

992

403

5.7

5

Juvenile

9/29/99

1170

1186

540

15

12

Sub-adult

10/20/99

801

919

354

4.2

4

Juvenile

10/20/99

845

963

387

5

4

Juvenile

10/20/99

1009

1132

445

8.8

6

Sub-adult

*Maturity classification based on age and total length of fish.

 

Our sampling methods proved to be effective in catching lake sturgeon greater than 700 mm, with a mean total length of fish captured in 1999 of 996 mm (Table 1). We only captured two fish less than 700 mm (Figure 3). This reflects more the selectivity of our sampling gear and methodology rather than smaller size classes being absent from the population. Our gill nets (with few panels of 4-inch stretch mesh or less) and setlines targeted primarily larger fish. Divers indicate they have seen a fairly even distribution of size classes in the river.

Figure 2. Relationship of age vs. length of lake sturgeon caught in the lower Niagara River, 1998-99.

Figure 2. Relationship of age vs. length of lake sturgeon caught in the lower Niagara River, 1998-99.

 

Figure 3. Length distribution of lake sturgeon caught in the lower Niagara River, 1998-99.

Figure 3. Length distribution of lake sturgeon caught in the lower Niagara River, 1998-99.

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Ultrasonic Biotelemetry

Ultrasonic tags in lake sturgeonConducting biotelemetry for lake sturgeonSince August 1998, 19 fish have been fitted with ultrasonic transmitters to monitor their long-term movements in the lower Niagara River and its confluence with Lake Ontario (Table 3). Tags were attached externally to either the dorsal fin, when suitable tissue was available, or through the dorsal scutes. Several sonic tags have become ‘idle’ (e.g., lost tag) as indicated by prolonged stationary fixes, while other tags/fish have not been located since shortly after tagging (i.e. absent) (Table 3). Tag retention (track duration) averaged only 60 days among those tags that are currently ‘idle.’ Two adult fish (#293 and #257) have not been located since mid-June, the end of the suspected spawning period. Currently, we are actively tracking six fish, with five fish absent, and eight ‘idle’ tags (Table 3).

Table 3. Tagging data for ultrasonic tagged lake sturgeon captured in lower Niagara River, 1998-99. Tracking status as of 12/22/99.

Fish No.

Mount

No. Fixes

Date Capture

Date of Last Fix

Track Duration (d)

Tracking Status

266

scute

37

8/1/98

10/20/98

81

idle

347

dorsal

19

8/12/98

11/9/98

90

absent

338

dorsal

23

8/14/98

11/9/98

88

idle

356 (’98)

dorsal

33 *

8/14/98

4/26/99

259

recap

248

scute

31

8/26/98

12/11/98

108

idle

239

scute

26

8/28/98

10/9/98

43

idle

293

dorsal

7

4/27/99

6/16/99

51

absent

356 (’99)

scute

4

4/28/99

5/11/99

14

idle

257

dorsal

12

4/28/99

6/9/99

43

absent

455

dorsal

31

4/28/99

12/22/99

239

active

275

dorsal

22

5/5/99

12/22/99

231

active

96

dorsal

12

5/18/99

6/21/99

34

idle

2237

dorsal

17

6/3/99

11/8/99

158

active

374

scute

9

7/16/99

8/19/99

35

idle

87

dorsal

17

7/23/99

12/22/99

152

active

284

scute

3

7/23/99

7/27/99

5

absent

2228

scute

14

8/4/99

10/20/99

78

idle

2246

dorsal

5

8/6/99

9/28/99

54

absent

5-10

scute

9

8/19/99

12/22/99

126

active

446

dorsal

6

9/29/99

12/22/99

84

active

* #356 captured in 1998 contains fixes (4/12/99 and 4/26/99) prior to being recaptured and re-tagged in 1999.

 

In general, our tagged lake sturgeon inhabit both the Niagara River and Lake Ontario at its confluence with the river (Figure 4, Table 4). Fish in the lake (within our tracking ‘circuit’) are very seldom found outside the confluence of the river (Figure 4, Table 4). Juvenile lake sturgeon seemed to prefer nearshore, slow water currents (mean bottom velocity 0.19 m/s), primarily remaining where they were collected, in Peggy’s Eddy and the Queenston Long Drift (Figure 4, Tables 4 & 5). Adults seemed to prefer the faster currents (mean bottom velocity 0.37 m/s) of the river and its confluence with the lake (Figure 4, Tables 4 & 5). Juveniles (mean depth 10.4 m), sub-adults (mean depth 9.3 m), and adults (mean depth 10.6 m) occupied similar depths (Table 6). Overall, lake sturgeon occupied depths ranging from 2.3 to 25.3 m with a mean depth of 10.3 m (Figure 5, Table 6).

 

Table 4. Macro-habitat (river vs. lake) and within-habitat current preferences of different life stages of lake sturgeon in lower Niagara River, 1998-99.

       

River

Lake

Life Stage

No. Fixes

Percent River

Percent Lake

Percent Eddy

Percent Main

Percent Confluence

Percent Main

Juvenile
(<1000 mm)

208

90

10

68

32

100

0

Sub-adult
(1000-1200 mm)

45

56

44

60

40

100

0

Adult
(>1200 mm)

84

64

36

11

89

93

7

All fish

337

79

21

56

44

97

3

 

Table 5. Average velocities of tagged lake sturgeon in lower Niagara River and its confluence with Lake Ontario, 1999.

Life Stage

No. Measurements

Average Surface Velocity (m/s)

Average Bottom Velocity (m/s)

Juveniles (<1000 mm)

7

0.18

0.19

Sub-adults (1000-1200 mm)

12

0.41

0.27

Adults (>1200 mm)

40

0.52

0.37

 

Adult lake sturgeon generally occupied two areas in the river during preferred spawning temperatures (13 to 18 oC literature range; May - June); the mouth of the river at Fort Niagara and the ‘red cliffs’ region from Stella Niagara upstream to Lewiston (Figures 4 & 6). On 5 June 1999 (water temperature 16 oC), three of five adult fish were located in close proximity to one another in the ‘red cliffs’ region (Figure 6, rkm 9). We have identified these areas as potential spawning sites in the lower river.

 

Figure 4.  Locations of sonic-tagged lake sturgeon in the lower Niagara River and Lake Ontario, 1998-1999.

Figure 4.  Locations of sonic-tagged lake sturgeon in the lower Niagara River and Lake Ontario, 1998-1999.

 

Table 6. Depth preferences among different life stages of ultrasonic tagged lake sturgeon,
1998-99.

Life Stage

No. Measurements

Average Depth (m)

Minimum Depth (m)

Maximum Depth (m)

Juveniles
(<1000 mm)

179

10.4

2.3

25.3

Sub-adults
(1000-1200 mm)

36

9.3

5.0

22.1

Adults
(>1200 mm)

81

10.6

5.8

23.8

All fish

296

10.3

2.3

25.3

 

Figure 5. Depth distribution of lake sturgeon caught in the lower Niagara River, 1998-99.

Figure 5. Depth distribution of lake sturgeon caught in the lower Niagara River, 1998-99.

 

Figure 6. Seasonal movement of five adult lake sturgeon in the lower Niagara River and Lake Ontario. River kilometer zero represents the mouth of the river. Positive river kilometers represent river locations and negative numbers represent lake locations.

Figure 6. Seasonal movement of five adult lake sturgeon in the lower Niagara River and Lake Ontario. River kilometer zero represents the mouth of the river. Positive river kilometers represent river locations and negative numbers represent lake locations. Disconnected lines indicate when a fish was ‘absent’ from the tracking area or when the interval between tracking events was greater than 14 days (e.g. we did not rack between 8 November and 22 December).

 

The substrate composition in ‘high use’ areas was surveyed using a Ponar dredge. In the eddy environments substrate was made up of silt, sand, and gravel. As flow increased, on the outside of eddies and in the main current, successive dredges collected very little substrate particles. In these areas, the substrate was characterized as hard bottom. The benthic fauna in the eddies consisted primarily of Oligochaetes, Chironomids, Mollusks (Dresseina sp., snails, fingernail clams), and Amphipods. No diet studies have been performed.

Twenty-four hour tracking events occurred on August 31, September 2, and September 3, 1998 to investigate the diel movement of tagged lake sturgeon. Prior to our study, we hypothesized that (1) lake sturgeon may be utilizing deeper waters (> 15 m) during the day then moving into shallow waters (< 10 m) to feed at night; and, (2) some fish may occupy the lake during the day and move into the river at night, particularly at or near its mouth. These suspicions were not confirmed by our sample of ultrasonic tagged fish. In general, fish did not exhibit large-scale movement patterns between day and nighttime hours. However, fish did appear to be more active at night, as indicated by increased localized movements. Unfortunately, we were unable to conduct more 24-hour tracking with greater sample sizes of fish, so we cannot draw any significant conclusions from the diel movement data.

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Genesee River

In a cooperative effort with New York State Department of Environmental Conservation (NYSDEC) Region 8, Avon and Endangered Species, and U.S. Geological Survey, Tunison Laboratory of Aquatic Science, we are determining the habitat suitability for, and the present utilization of lake sturgeon in the Genesee River below Rochester. Our office deployed 10-inch stretch gillnets in the river to catch adult lake sturgeon potentially migrating during the suspected spawning period. In addition, during the summer months (July and August), experimental gillnets were fished to capture young lake sturgeon. No lake sturgeon were caught after 27 gillnet nights of effort (Table 7). According to the HSI for lake sturgeon (Threader et. al. 1998), suitable spawning habitat (0.5-2.5 m depth, 50-240 cm/s velocity, 10-18o C, and boulder/cobble substrate) was found below the lower falls. Sub-optimum juvenile habitat was found in the downstream areas of the river. The Rochester Embayment is listed as an Area of Concern, therefore the effects of chemical contamination on the suitability for lake sturgeon cannot be ignored. However, no water chemical analysis was done in 1999.

 

Table 7. Lake sturgeon sampling effort in lower Genesee River, 1999.

Method

Total Nights

Total Hours

10" Gillnet

13

287.3

Exp. Gillnet

14

309

All

27

596.3

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HATCHERY SUPPORT

Oswegatchie River

The Oswegatchie River lake sturgeon project is in cooperation with the New York State Department of Environmental Conservation (NYSDEC) and the State University of New York - College of Environmental Science and Forestry. To determine the success of the restoration effort several objectives were set forth. These included determining the distribution, movement, and habitat utilization of stocked juvenile lake sturgeon in the Oswegatchie River, tributary to the St. Lawrence River at Ogdensburg, NY (Lowie et al. 1999).

Sampling continued to determine downstream distribution of stocked juvenile lake sturgeon at selected sites. Gillnetting was conducted on 15 nights consisting of 50 individual gillnet sets (4 sampling periods, May - Oct.). This yielded 264 lake sturgeon comprised of 5 year classes (24 specimens age not determined). A total of 23 lake sturgeon were captured from the 1999 stocking year class, 45 from the 1998 stocking year class, 127 from the 1997 year class, 44 from the 1996 year class, and 1 lake sturgeon from the 1995 stocking year class. The 23 lake sturgeon from the 1999 stocking year class were captured during the October sampling period and were released from the hatchery less than one month prior. Table 8 shows mean total length for each stocked year class collected in 1998 and 1999.

Movements of 1998 radio tagged lake sturgeon were monitored in 1999, and fish continue to show a pattern of downstream movement. The tagged naturalized lake sturgeon eventually displayed the same pattern as the newly stocked hatchery sturgeon but moved downstream at a much slower rate. As shown in the 1998 data (Lowie et al. 1999), newly stocked lake sturgeon remain in the upper reaches of the sampled area. As lake sturgeon remain in the system, they tend to move to the middle and then downstream reaches of the river. Compared to 1998, a shift in dominant year class composition was obsserved at the four standardized sampling sites. This supports the telemetry data showing the same overall downstream movement of stocked juvenile lake sturgeon.

 

Table 8. Mean total length of stocked lake sturgeon caught in the Oswegatchie River, 1998 and 1999.

Stocked Year Class

1998 Mean Total Length (mm)

1999 Mean Total Length (mm)

1995

560.9

535

1996

456.5

483.4

1997

271.5

372.1

1998

306.5

1999

252.2

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LAKE STURGEON SIGHTING PROGRAM and PUBLIC EDUCATION

Anecdotal information of lake sturgeon sightings has been reported by recreationalists and commercial fishermen since 1994. In 1998, we significantly increased our public outreach efforts. Lake sturgeon ‘Sighting Alert’ cards were distributed to marinas, bait shops and boat launches; posters were displayed in dive shops; LGLFRO web pages were created; and a ‘Sighting Alert’ notice was posted in the NY State Fishing Regulations Guide. In each sighting report, participants recorded general information regarding the sturgeon siting (date, time, location, number and size of fish) as well as habitat variables (depth, water temperature, substrate composition, and vegetative abundance). As a result of our increased educational effort, 86 reports of 120 lake sturgeon (in 7 waterbodies) were filed by our office in 1998. In 1999, 77 reports of 119 lake sturgeon (in 16 waterbodies) were recorded. The increase in the number of waterbodies where lake sturgeon were sighted in 1999 is likely due to NYSDEC stocking efforts and increased public awareness. All new waterbodies reported in 1999 have received stocked lake sturgeon either directly into or in adjacent waters over the past three years.

The majority of reports/sightings have been received from the Niagara River (Figure 7). More detailed analysis of this information has provided and continues to provide questions/hypotheses for us to investigate, but also additional opportunities to better assess the populations of the upper and lower river. In 1999, the most substantial observation was the amount of lake sturgeon caught by anglers in the lower river in the fall. In each of 1998 and 1999, over 20 lake sturgeon, primarily 36 inches or less, were caught in a 1.5 to 2 month period.

Also in 1999, we conducted a second mass dive event in the upper Niagara River, the first being held in 1998. Eight boats and a total of 26 divers participated in each dive. The purpose of the "mass dives" was to better identify lake sturgeon distribution and abundance in the river. The "mass dives" provided excellent educational opportunities for the diving community to interact with LGLFRO biologists and learn more about the lake sturgeon. They also allowed LGLFRO biologists to further explore the potential for diver sightings to be used as a method of lake sturgeon population and habitat assessment.

As a member of the Central Great Lakes Bi-National Lake Sturgeon Group, our office participated in filming our lake sturgeon research project for production of a Great Lakes’ sturgeon educational video. Specifically, footage was taken of the diving activity, with divers

Figure 7.  Lake sturgeon sightings in the Niagara River area.

Figure 7.  Lake sturgeon sightings in the Niagara River area.

 

capturing lake sturgeon underwater; gillnetting; and, sonic tracking. Also, footage was taken of the Niagara Falls area and a personal interview with Chris Lowie.

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DISCUSSION

Preliminary results are presented in the sections above and will not be reiterated in this section. Here, we discuss the implications our work will have on the recovery of lake sturgeon. Our Lake Sturgeon Program activities are at various stages of maturity. With regard to interagency coordination and its benefits to lake sturgeon recovery, the LGLFRO has an important role in information transfer and coordination of basin-wide restoration efforts in the Great Lakes. Data collection and an analysis on the genetic variability of populations is being coordinated through this office. When available, this information will provide resource managers with the answers needed to implement sound restoration and management practices, particularly where stocking is occurring.

The population and habitat assessment of lake sturgeon in the Niagara River is in its initial stages of identifying key spawning and feeding areas. We feel this is priority information needed to protect and enhance this population. The Niagara River population may provide another source of broodstock for restoration efforts in New York and adjacent waters. Information from scientific collections and anecdotal reports suggest the population is self-sustaining, with annual recruitment occurring and the presence of adult fish. Diver capture has proven to be an effective sampling method. We need to enhance this component of our scientific study. Diving can be a very useful tool, not only to capture lake sturgeon but to conduct habitat assessments and confirm spawning activity.

The Oswegatchie River restoration project, which encompasses evaluating the success of NYSDEC’s hatchery product and stocking strategies, has had tremendous success in identifying the distribution, survival, growth, and diet of stocked lake sturgeon. This data, in addition to the Genesee River assessment, will provide important information directing future restoration activities in New York’s Great Lakes and inland waters.

Plans for 2000

We will further analyze the movement data of our tagged lake sturgeon, looking specifically at any differences that may exist between the different size/maturity classes among several variables (e.g., total distance moved, average distance moved between fixes, and upstream vs. downstream movement between fixes). During the 2000 field season, we plan to focus on monitoring adult individuals by deploying 6 more ultrasonic tags on fish caught in March-May. Daily tracking will occur on all tagged adults found in the study area to identify potential spawning areas. Egg mats will be placed in these suspected areas to confirm spawning. Other tagged lake sturgeon will continue to be monitored for movements and habitat utilization. Additional individuals will continue to be collected to support ongoing collaborative work comparing the age, growth, status, and genetics of Great Lakes lake sturgeon populations. Select anglers will be provided with tool boxes to assist us in collecting biological data from by-caught lake sturgeon. Habitat parameters will also continue to be collected throughout the study. We hope to enhance the diving component of the Niagara River research project.

We will survey for adult, migrating lake sturgeon in the Genesee River as well as collect a second year of habitat data. If no lake sturgeon are found and habitat data appears positive, we likely will implement a cooperative research initiative to stock Niagara River lake sturgeon into the Genesee, and monitor their distribution, survival, growth, and habitat utilization.

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REFERENCES

Booker, W.V. and eight authors. 1993. Framework for the management and conservation of paddlefish and sturgeon in the United States. National Paddlefish and Sturgeon Steering Committee. USFWS, Washington D.C. 41pp.

Carlson, D.M. 1999. A lake sturgeon recovery plan for New York State: revisions to the 1994 plan. NYSDEC, Watertown. 32pp.

Hill, T.D. and J.R. McClain, editors. 1999. Activities of the Central Great Lakes Bi-National Lake Sturgeon Group. USFWS, Alpena Fishery Resources Office, Alpena, MI. 63pp.

Lowie, C.E., T. Hughes, and S.L. Schlueter. 1998. Great Lakes Native Fish Restoration: Lake Sturgeon, FY1997 Fisheries Stewardship Proposal, 1998 Progress Report. 8pp.

Lowie, C.E., T. Hughes, and S.L. Schlueter. 1999. Great Lakes native fish restoration: lake sturgeon, 1998 summary report of Niagara River and Oswegatchie River research projects. USFWS-LGLFRO, Amherst, NY, Administrative Report 99-01. 15pp.

Lowie, C.E. 1999. Great Lakes lake sturgeon genetics status assessment: an analysis of samples, methods, and standardization. USFWS-LGLFRO, Amherst, NY, Administrative Report 99-02. 11pp.

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. 37pp.

United States Fish and Wildlife Service. 1995. Great Lakes Fishery Resources Restoration Study - Report to Congress. Dept. of Interior, Washington, D.C. 196pp.


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