Spatial genetic structure of upper Great Lakes burbot (Lota lota)

The population abundance and distribution of many Great Lakes fish species, particularly those that are adapted to cold water, have changed greatly in recent times due in part to changes in physical lake and biotic environments. Burbot (Lota lota) is an understudied cold water benthivore of conservation concern. To characterize levels of genetic diversity and spatial genetic structure associated with historical phylogeographic isolation or contemporary reproductive isolation, microsatellite genotypes and mitochondrial DNA sequences were analyzed for burbot (n = 253) collected from 14 open water locations in Lakes Huron, Michigan, and Superior and the upper St. Clair River. Spatial variation in levels of diversity and degree of genetic distinction among samples in different geographic locations was most evident over broader geographic scales between Lake Superior and Lakes Michigan and Huron. Members of open-water sampling locations within basins did not differ significantly in microsatellite allele or mtDNA haplotype frequency. Data from this study and from previous results in other North American locations indicated that burbot sampled from the upper Great Lakes likely originated from multiple glacial refugia, and that geographic representations were admixed at the lake basin level. Analyses differentiating populations of burbot will inform managers how to appropriately target the genetically differentiated populations to support species management.