2012 Great Lakes Lake Sturgeon Coordination Meeting
Dec. 2-3, 2012 Sault Ste. Marie, MI 49783

Poster Abstracts

Population dynamics of lake sturgeon in the lower Niagara River: revisiting and reassessing a recovering population 10 years later.

Dimitry Gorsky - US Fish and Wildlife Service, Basom, NY

Description: Evidence from assessments carried out in the lower Niagara River between 1998 and 2002 suggested that the lake sturgeon population may be recovering. During that assessment less than 100 lake sturgeon were sampled. Many of them were observed to be young and sexually immature fish. There appeared to be a lack of older, sexually mature fish prompting the investigators to believe this population was in recovery and awaiting the onset of sexual maturity to continue the recovery. In 2012, we began a population assessment of this population using similar methods and locations as the previous assessment. During our assessments, we observed much higher catch rates and a shift in the age structure toward older fish that appear to be of the same cohort that was sampled in the earlier assessment. We also observed a lack of older fish, but did observe several sexually mature fish. Analysis of population measures, catch rates and habitat use gives us a closer understanding of the lake sturgeon population in the lower Niagara River and insight into how relict populations may undergo recovery.

Sex, maturity, and changing spawner demographics of lake sturgeon in the lower Niagara River

Gregory R. Jacobs - U.S. Fish and Wildlife Service, Lamar, PA
Molly A. H. Webb - U.S. Fish and Wildlife Service, Bozeman, MT
Dimitry Gorsky - U.S. Fish and Wildlife Service, Basom, NY
John A. Sweka - U.S. Fish and Wildlife Service, Lamar, PA

Description: Evidence suggests that the lake sturgeon population in the lower Niagara River is recovering, largely driven by a small number of large cohorts from the mid-late 1990s. Based on estimated ages from pectoral fin ray samples, there was a predominance of lake sturgeon aged 12-17 years in this population during 2012. As fish from these cohorts reach maturity, changes in the sex ratio and age composition of spawning lake sturgeon are expected to occur over the next several years, given differences in maturation and spawning periodicity among sexes. As such, these changes can have important implications for population growth, or even persistence, we began monitoring the age, sex, and maturation stage of lake sturgeon in the lower Niagara River during spring of 2012. To assign sex and maturation stage, we quantified the concentration of testosterone and 17ß-estradiol in blood serum samples using radioimmunoassay. We then confirmed blood plasma results and quantified error rates using histological analysis of gonad biopsies. Ages were estimated by enumerating annuli from cross-sections of the leading pectoral fin rays. Our results depict a snapshot of the lower Niagara River lake sturgeon spawning population in 2012, providing us with important baseline estimates of age and sex ratio of spawning fish which can be combined with mark-recapture assessment, genetic analyses, and further monitoring to construct population viability models.

Milestones in NY Lake Sturgeon Restoration

Dawn Dittman - U.S. Geological Survey, Cortland, NY

Description: This will be a description of the recent milestones in Lake Sturgeon in New York. These will include numbers and size distributions in target waters and the current reproductive status of the stocked fish.

Enhancing Michigan’s virtual and place-based educational opportunities and community stewardship using charismatic lake sturgeon in coupled human - Great Lakes ecosystems

Kim Scribner and John Bauman - Department of Fisheries and Wildlife Michigan State University, East Lansing, MI

Description: Educating K-12 students and the general public about Great Lakes ecosystems and inter-dependencies between fish communities and physical and biological processes of streams used seasonally for spawning and foraging is critical to increase awareness of the need for stewardship activities. We have developed a virtual (e-learning) web site based on 12 years of data collected on the lake sturgeon population in Black Lake, MI. The site contains extensive background information on lake sturgeon ecology through all life stages. Science, technology and math curricula have been developed that are based on empirical long-term data from the Black Lake Project.

Materials can be obtained at: http://www.fw.msu.edu/glsturgeon

Oral presentations
December 3-4, 2012

Magnitude of Effect of Hydro-electric Operations on Lake Sturgeon Abundance in Ontario Rivers

Tim Haxton, Ontario Ministry of Natural Resources, Peterborough, ON

Dams and lake sturgeon have a long history, which has been extended within the last century to hydro-electric facilities. Given the migratory nature of lake sturgeon, dams generally have an adverse effect on their populations. These effects can be exacerbated at hydro-electric facilities as flows and water levels are dramatically and frequently altered. Qualitatively, the effects of hydro-electric facility operations on lake sturgeon are generally known. However, despite the elongated history between the two, these effects have not been quantified (i.e., how much are lake sturgeon affected). The objective of this study was to ascertain the magnitude of effect (d) different hydro-electric facility operating regimes have on lake sturgeon abundance. Also, it was to quantify the effectiveness of remedial actions intended to offset these effects. A standardized index netting program was conducted throughout Ontario in unimpounded rivers and rivers managed as run-of-the-river, peaking and winter reservoir systems. Overall, 23 rivers were assessed in three Ministry of Natural Resources Administration Regions and a total of 362 lake sturgeon were sampled. The magnitude of effect of the hydro-electric facilities on lake sturgeon abundance was quantified as large (i.e., d = 0.8). Partitioned among water management regime types, this effect was lowest on run-of-the-river systems and greatest on both peaking and winter reservoir systems. Adults appear to be most affected in peaking systems whereas the magnitude of effect for juveniles was lowest in run-of-the-river systems. Despite the potential adverse effects of dams on lake sturgeon, only two hydro-electric facilities in Ontario have employed remedial actions to mitigate effects for this species. A spawning shoal was constructed downstream of Chenaux Generating Station on the Ottawa River in December 2008, however the effectiveness of this project would not yet be detectable at the time of this study. Flow augmentation during the spawning period was employed in the Kaministiquia River from 2004 – 2011. The magnitude of effect on the sturgeon population in that system was considerably less than observed for peaking systems suggesting that the management actions employed benefited lake sturgeon, specifically juveniles. However, this only represents one location. Additional mitigation and monitoring would be required to ascertain the true effectiveness of remedial actions for lake sturgeon on regulated rivers in the province.

Effects of Stocking on the Genetic Diversity of Lake Sturgeon

Amy Welsh, West Virginia University, Morgantown, WA

Our objective was to assess the genetic diversity of stocked lake sturgeon using neutral and adaptive genetic markers. Two stocked locations were studied: Oneida Lake, NY and the Menominee River, MI/WI. At Oneida Lake, two stocking scenarios were used: a single large-scale stocking from one source, and a multi-year stocking from a different source. Using twelve microsatellite loci, we evaluated whether stocking over multiple years increased the genetic diversity and effective population size of the resulting offspring. The resulting stocked population from multi-year stocking was less genetically different from the source population with similar levels of genetic diversity. However, the single-year stocking event had lower genetic diversity than its source population, resulting in those offspring being very different from their source population. Despite better genetic representation, the multi-year stocking program resulted in a very low effective population size, likely due to high variance in family sizes. At the Menominee River, stocked sturgeon were used to supplement an existing population. Using both neutral (microsatellite loci) and adaptive markers (MHC), rare alleles were not represented in the hatchery-produced offspring. Hatchery- and wild-produced offspring were genetically differentiated at neutral loci but did not differ at the adaptive loci, indicating that strong selection may eliminate genetic differences between hatchery and wild fish. Both studies show that stocking practices can reduce the genetic diversity of fish populations, primarily by inadequate representation of alleles in the source population.

Lake Sturgeon Sampling Efforts in the Pennsylvania Waters of Lake Erie

Jeanette Schnars, Tom Ridge Environmental Center, Erie, PA

Historically, Lake Sturgeon (Acipenser fulvescens) have been known to inhabit Lake Erie along the shores of Erie County, Pennsylvania. Presently, there are few sightings annually many of which are not reported. This project has started an effort to routinely sample for Lake Sturgeon, determine optimal habitat through side-scan sonar, and create public awareness to formalize reporting. Sampling by baited set lines has been conducted during the 2011 and 2012 seasons in hopes of collecting fin clips for genetic analysis. Presently, no Lake Sturgeon have been caught. Side-scan sonar data was collected during the 2012 season to determine if optimal habitat still exists where Lake Sturgeon once spawned. Finally, outreach of the project through watch cards and posters has increased awareness to formalize live/dead Lake Sturgeon sightings along the Pennsylvania Lake Erie coastline. This two-year project has been funded by the Pennsylvania Coastal Zone Management program and efforts will continue through the 2013 season.

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