MARCH 2000

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.

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.

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.

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.

Information Needs

The following are needs identified by participants:

• Stock Identification
• Mixed Stock Identification
• Stock Variation
• Characterize Successfully Reproductive Populations
• Identify Best Sources for Stocking
• Identify Best Stocking/Mating Strategies
• Identify Genes Responsible for Survival
• Identify Fitness and Domestic Selection
• Genetic Tagging
• Individual Identification
• Impact of Stocking on Natural Populations

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.

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.

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.

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.

To 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.

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.

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

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

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.

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

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.

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

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, 10-18^o 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.

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.

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.

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

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.

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.