Abstracts - Poster Presentations

Bauman, John - Population Assessment of Lake Sturgeon in the St. Marys River

Description: Lake Superior State University’s Aquatic Research Laboratory has for 5 years conducted set-line surveys from the lower to upper portions of the St. Mary’s River, Michigan. This survey targeted sub-adult and adult lake sturgeon. Results will help managers conduct accurate population estimates before rehabilitation or conservation efforts can be initiated for the St. Mary’s Lake Sturgeon population.

Dittman, Dawn E. and Emily C. Zollweg - Assessment of Habitat Use by Stocked Lake Sturgeon in the Genesee River [view poster (818 Kb pdf)]

Description: Lake sturgeon (Acipenser fulvescens) has been identified by fisheries managers as a key target species for recovery and restoration in the Lake Ontario - St. Lawrence River system. The Genesee River is one of the major tributaries to Lake Ontario and part of the Rochester Embayment Area of Concern. In September 2003, 900 juvenile lake sturgeon were released at river kilometer 9.1. Released sturgeon had an average length of 210mm and an average weight of 43.6g. Experimental gill netting was conducted from river km 3 to 9.1. In this first year of assessment 94 of the 900 stocked lake sturgeon were recaptured. The most successful recapture site was the first deep area downstream of the release site, (river km 8.2). It averages over 6 m depth and has gravelly/shelly substrate. The second most successful capture site (rkm 6) is a deep spot (9 to 10m) with gravelly, rocky substrate. In November 2003, five recaptured fish at site 1 averaged 242mm. Nine fish captured 8-31 to 9-02, 2004 averaged 347mm and 162g with the largest fish measuring 408mm and 248g. These results indicate that the juvenile sturgeon are successfully using the Genesee river habitat. Results of this research in the Genesee River will provide information needed for future steps in the restoration and enhancement of lake sturgeon in Lake Ontario and associated tributaries.

Drauch, Andrea M., Brant. E. Fisher, and O. E. Rhodes, Jr. - Resolving the Genetic Composition of the White River Lake Sturgeon Population: Implications for Conservation and Management

Description: Stocking has been employed in the rehabilitation of lake sturgeon populations for the past twenty years. A concern of particular relevance to this conservation strategy is the maintenance of genetic integrity within particular stocks. Individual lake sturgeon stocks may be adapted to local environmental conditions, and the introduction of non-native lake sturgeon to a watershed may jeopardize the survival of the released cohort, as well as the persistence of native conspecifics by contributing maladaptive genes to the gene pool. Recently, several state agencies have expressed interest in reintroducing lake sturgeon to the Ohio River drainage system. A single relict population of lake sturgeon, found in the White River, is thought to exist in this drainage. It is suspected that the population primarily consists of remnant individuals, however the possibility exists that fish from reintroduced populations in the Missouri or Mississippi Rivers have strayed into the White River system. Population assignment tests were performed using multilocus genotype data from ten microsatellite loci to resolve the genetic composition of the White River population. The results of this analysis will assist in the selection of an appropriate source population for future lake sturgeon reintroductions to maintain the genetic integrity of the Ohio River stocks.

Furman, Amy, and Barbara I. Evans - Embryogenesis and Larval Development of Lake Sturgeon (Acipenser fulvescens)

Description: We are interested in the early functional morphology of lake sturgeon as it applies to their survival. Fertilized lake sturgeon eggs were obtained on May 6, 2004. Males and females were captured from the Sturgeon River by the MDNR and their gametes removed. The eggs were fertilized on site and mixed with clay to prevent clumping. The fertilized eggs were then transported to LSSU and kept at 13°C on a light regimen of 15L:9D in a Lab-Life Biotronette Plant Growth Chamber. For embryonic development, 3 eggs were maintained in a petri dish filled with fresh lake water (changed daily) while the remaining eggs were reared in egg trays at the LSSU Aquatic Research Laboratory. After hatching, all larvae were transferred to aquaria in the growth chambers. Development was monitored using a Leica GZ6 dissection microscope and recorded using a Panasonic Super Dynamic WV-CP450 Color CCTV Camera. The images were then digitally captured and processed in iMovie for iMac. The sketches were drawn in pencil, then scanned and processed using HP PrecisionScan Pro and iMovie. The lake sturgeon were observed from fertilization to 70 days post hatch (dph). The heart was first seen pumping at 9 days post fertilization (dpf). Hatching occurred 10 dpf , but the yolk was not resorbed until 15 dph. The jaw and eye could been seen developing in the embryo, but were not fully formed upon hatching. Jaw articulation was first observed 9 dph, while eye movements were not observed until 21 dph. Pectoral fins are first evident after 3 dph and very small fin rays are visible 10 dph. Rudimentary barbels were first observed at 4 dph. The characteristic rostrum of the adult lake sturgeon starts to take shape 10 dph. The fish survived well past our expectations. By characterizing the early development of lake sturgeon we hope to better understand the constraints on their early survival.

Evans, Barbara I. and Amy Furman - Development of the Retina in Larval Lake Sturgeon (Acipenser fulvescens)

Description: The visual capabilities of lake sturgeon were assessed during their early life history. Lake sturgeon eggs from the Sturgeon River were obtained the day of fertilization, courtesy of the MDNR (E. Baker). Eggs were then reared under controlled conditions at 13oC and a 15hL: 9hD light cycle. At various times during development, individuals were fixed in Bouin's, embedded in plastic resin and sectioned at 3 microns to observe the state of the retina. At hatching (10 days post fertilization) the eyes were not yet functional. The eyecup had formed, but no lamination of the neural retina was present and the photoreceptor cells had not differentiated. The lens was only partially formed, but the pigmented epithelium was present around the retina. At 10 days post hatch (dph) single cone photoreceptor cells were present; the retina showed distinct layers and the lens appeared to be fully differentiated. At 54 dph, the retina appeared to have two cone types 1) a small cone type with a tapered outer segment and an oil droplet in the inner segment and 2) a larger cone with a wide rod-shaped outer segment. No rods were apparent at this time; however, the retina has many more photoreceptors than ganglion cells, a neural pattern typical of rods. The timing of retinal development in the lake sturgeon indicates vision is not crucial to survival of the early larval stages. The apparent lack of rods, but convergent retina suggests poor visual acuity but also poor low light vision. Ongoing work will further our understanding of the limitations of vision during the early larval development of lake sturgeon.

Haxton, Tim - Changes to a lake sturgeon spawning population over 50 yrs

Description: Dubrieil and Currier assessed a lake sturgeon spawning population below Chats Generating Station (Ottawa River) in 1949 and sampled over 400 lake sturgeon. I repeated their project in 2001, 2003 and 2004. I will be presenting changes/similarities observed in the spawning populations including size distribution, growth and timing of spawning. A general description of the spawning areas will be provided along with historical changes.

Kornely, Greg W. - Hook & Line Sturgeon Fishery in the Menominee River, Wisconsin-Michigan Boundary Water

Description: There is an annual hook and line lake sturgeon fishery that takes place on the Menominee River, the boundary water between Wisconsin and Michigan. Since 1983 registration of harvested fish has been mandatory. The annual harvest has ranged from 13 to 210 lake sturgeon. Harvest data since then will be described, highlighting changes in fishing pressure and regulations. Future management will be proposed.

Yule, Dan, Gary Cholwek, Henry Quinlan, and Tom Doolittle - Lower Bad River Acoustic Mapping Project [view poster (251 Kb pdf)]

Description: Our project goals were to map and quantify habitat in the lower Bad River and nearby coastal waters of Lake Superior and to examine habitat usage by juvenile sturgeon previously captured in trawl surveys. We surveyed the lower 9.6 km of the Bad River, Wisconsin, and a 3.2 by 2.0 km segment of Lake Superior near the Bad River mouth. Three substrate categories were identified in the Lower Bad River: clay (very densely packed with fine particles between 1/2048 mm to 1/256 mm diameter, a mixture of clay and sand and sand (1/16 to 1/4 mm). Five substrate categories in Lake Superior were identified: clay (particles between 1/2048 and 1/256 mm diameter), sand with silt (1/256 to 1/8 mm), sand (1/16 to 1.5 mm), coarse sand/medium pebbles (0.5 to 10 mm) and cobble/boulder (64 to > 256 mm). Previously captured sturgeon were associated with relatively deep water with bottom comprised largely of sand. Future fish surveys can be designed to proportionally sample all habitat types for improved description of juvenile lake sturgeon habitat preferences in the Bad River and other Lake Superior tributaries.

Zollweg, Emily, John Weisser, Rob Elliott, Henry Quinlan, Jim Boase, Scott Koproski, and Adam Kowalski, Nancy Auer, Ed Baker, Doug Carlson, Tim Haxton, Mike Thomas, Jerry Weise - Great Lakes Lake Sturgeon Tributary Database and Geographic Information System Demonstration

Description: This interactive GIS application and metadatabase have been designed to compile the available lake sturgeon data sources to help focus restoration and research activities on priority lake sturgeon waters.
The web application functions much like a GIS database, allowing selection of various data layers and enabling the user to query available data to find specific information of interest. All known lake sturgeon waters within the Great Lakes Basin (extirpated, historic, reintroduced, and current) are included. Where available, information is referenced for presence of adults, juveniles, and subadults, and whether spawning has been observed, egg deposition documented, and larvae surveyed for. Data fields reporting whether contaminant, genetic or age samples were collected, year(s) data collected, investigator(s) involved, and citations for available reports and publications and point of contact for additional information are included.

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