**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**

Assessment of the Population Genetic Structure of Lake Sturgeon

Amy Welsh¹ and Bernie May²

¹ SUNY-Oswego, Department of Biological Sciences, 7060 State Route 104, Oswego, NY 13126

² University of California – Davis, Department of Animal Science, 1 Shields Avenue, Davis, CA 95616

December 2008

ABSTRACT:

Many lake sturgeon populations remain well below their historic population sizes. Genetic data can provide important information to help guide management actions. By understanding the genetic structure of spawning populations, management actions can work to preserve natural genetic differences between groups of lake sturgeon. A thorough understanding of the structure of spawning populations can lead to valuable insights about non-spawning lake sturgeon. This life stage represents the bulk of a sturgeon’s life history, but little is known about it. Understanding their movement patterns during non-spawning times can help with the development of harvest regulations and can help with the detection of stocked fish. The goals of this study were to 1) include additional spawning populations from Lake Huron, Lake Erie, and Lake Ontario in order to achieve a Great Lakes-wide genetic representation of lake sturgeon population structure, 2) use mitochondrial DNA to achieve a phylogenetic perspective of lake sturgeon structure that may relate to the glacial history of the Great Lakes regions, and 3) determine the origin of non-spawning lake sturgeon captured throughout Lake Superior and in a commercial fishery in Lake Huron. All samples were analyzed at 12 microsatellite loci. Many of the spawning populations were also sequenced at the mtDNA control region and mtDNA data from various laboratories were compiled to achieve a range-wide perspective. The microsatellite data from the spawning populations were used to assign non-spawning individuals to their most likely population of origin. Spawning populations that were added to the analysis include Lake Nipissing (Lake Huron), Spanish River (Lake Huron), Grasse River (Lake Ontario), Black River (Lake Ontario), and Lake Champlain. Most populations showed significant genetic differences. The highest level of genetic differentiation was observed within Lake Superior and between Lake Superior and the other Great Lakes. The mtDNA analysis showed marked differences between the Hudson Bay drainage, the upper Great Lakes, and the lower Great Lakes. These differences indicate the possibility that lake sturgeon used multiple glacial refugia and dispersal routes back into glaciated regions. The population structure observed among lake sturgeon populations may be due to these natural historical processes. The microsatellite markers had sufficient power to detect the population origins of non-spawning sturgeon. In Lake Superior, most sturgeon remained geographically close to their spawning site of origin. Wolf River (Lake Michigan) sturgeon that were stocked into the St. Louis River (Lake Superior) were detected north and slightly east of the stocking site, but appear to remain restricted to the western arm of Lake Superior. In Lake Huron, the commercial fishery that operated in the southern portion of Lake Huron appeared to be targeting primarily St. Clair River sturgeon. However, a few Menominee River sturgeon were also captured.

For results of objective one see:

Welsh, A. T. Hill, H. Quinlan, C. Robinson, and B. May. 2008 Genetic Assessment of Lake Sturgeon Population Structure in the Laurentian Great Lakes. North American Journal of Fisheries Management 28:572–591.