Historical Biogeography and Lakescape Features Contribute to Stock Structure of Great Lakes Coregonids

Assessing the relative importance of historical biogeographic and contemporary events on stock structure is one of the major questions uniting basic and applied fisheries sciences. Genetic data analyzed in a hierarchical spatial context among individuals, and among populations at micro- and macro-geographic scales has been widely used to provide information on the degree of population structure and to estimate rates of gene flow among populations. We demonstrate that analytical designs can be employed that extends hypothesis-testing capabilities by combining phylogeographic data with information on the distribution, connectivity, and quality of habitat. We show that genetics data collected and analyzed at the level of individuals or populations can be used to examine ecological questions regarding degree of habitat permeability and potential negative consequences of anthropogenic disturbance. Microsatellite and mtDNA data from native coregonids (Coregonus artedi and C. hoyi) from the Great Lakes will be highlighted. Both species share common alleles and haplotypes from 2 major mitochondrial lineages but in significantly different frequencies suggesting contributions from multiple refugia but independent evolutionary trajectories over recent times. The extent of spatial variance in gene frequency differs between species reflecting differences in ecology and importance of hydrogeomorphological features within different lake basins.