Cooperative Fish and Wildlife Research Units Program: Wisconsin Fishery
Education, Research and Technical Assistance for Managing Our Natural Resources

We quantified genetic relationships among muskellunge Esox masquinongy from 15 locations in the Great Lakes to determine the extent and distribution of measurable population structure and to identify appropriate spatial scales for fishery management and genetic conservation. We hypothesized that muskellunge from each area represented genetically distinct populations, which would be evident from analyses of genotype data. A total of 691 muskellunge were sampled (n = 10-127/site) and genetic data was collected at 13 microsatellite loci. Results from a suite of analyses (including pairwise genetic differentiation, Bayesian admixture prediction, analysis of molecular variance, and tests of isolation by distance) indicated the presence of nine distinct genetic groups, including two that were approximately km apart. Geographic proximity and low habitat complexity seemed to facilitate genetic similarity among areas, whereas muskellunge from areas of greater habitat heterogeneity exhibited high differentiation. Muskellunge from most areas contained private alleles, and mean within-area genetic variation was similar to that reported for other freshwater fishes. Management programs aimed at conserving the broader diversity and long-term sustainability of muskellunge should consider the genetically distinct groups as independent fisheries, and individual spawning and nursery habitats should be protected to conserve the evolutionary potential of muskellunge.