Brood source identification and the effects of supplementation on muskellunge in the Great Lakes

Current muskellunge (Esox masquinongy) management in Great Lakes states and provinces calls for stocking muskellunge native to the Great Lake to re-establish sustainable populations that have previously experienced population declines or extirpation. Accordingly, native Great Lakes muskellunge brood sources must be identified or established to meet that need. Managers who seek to develop future muskellunge broodstocks benefit from knowledge of stock structure to better match the origin of hatchery fish to the locations in which they will be stocked. Therefore, our objectives were to (1) determine if the genetic structure of non-admixed Great Lakes muskellunge populations is consistent with a genetic stock model that can be described in terms of genetic stock identification and degree of stock isolation for the identification of potential brood sources, and (2) determine if significant admixture is present in Great Lakes muskellunge populations consistent with introgression between stocked and resident Great Lakes muskellunge . Fourteen microsatellite loci were used to characterize genetic diversity and structure of more than 1,800 muskellunge from more than 40 locations throughout the Great Lakes and associated inland drainages. Genetic diversity and molecular variance will be compared within and among various genetic structure models to identify possible influences of historical stocking and, ultimately, potential brood sources for Great Lakes muskellunge supplementation efforts.