Population structure of lake trout (Salvelinus namaycush) in a large glacial-fed lake inferred from microsatellite DNA and morphological analysis

Understanding the structure of intraspecific genetic and morphological diversity within and across habitats is a fundamental aspect of biodiversity research with conservation value. Atlin Lake is the largest lake in British Columbia, Canada, and contains relatively pristine populations of lake trout (Salvelinus namaycush) that are key components of the lake's fish community and local fisheries. Lake trout from Atlin Lake were examined for genetic and phenotypic variation using eight microsatellite DNA loci, body form, and colouration. Genetic assays were also conducted on lake trout from the adjoining Tagish Lake and from 17 other localities to provide spatial context for the variation within Atlin Lake. The genetic data suggested that there were three genetic subpopulations within the Atlin-Tagish lake system. Morphological analysis identified two morphological groups of lake trout within Atlin Lake. Genetic and morphological groupings in Atlin Lake were not associated with each other. A mixed-stock analysis of samples collected from Atlin Lake commercial and recreational fisheries suggested that all genetic subpopulations contributed to the fishery and that there was some contribution from fish originating from within Tagish Lake.