Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists
A Review of Muskellunge Population Genetics: Implications for Management and Future Research Needs
Loren M. Miller, John M. Farrell, Kevin L. Kapuscinski, Kim Scribner, Brian L. Sloss, Keith N. Turnquist, and Chris C. Wilson
Abstract.— At the first international Muskellunge symposium held in 1984, participants recognized that management agencies needed policies for sustainable management of native Muskellunge Esox masquinongy stocks. Identified research needs included documenting how genetic diversity was distributed within and among natural populations and evaluating effects of management actions on diversity. Here, we summarize research over the past three decades that has addressed these needs and provided additional genetic information useful to managers. We then suggest future research directions to fill information gaps and benefit from advances in genetic marker technology and methods of statistical inference. Genetic data support the existence of distinct regional lineages associated with the upper Mississippi River, Great Lakes, and Ohio River drainages, which all likely derived from Mississippian glacial refugia. Each lineage exhibits substructure, with numerous genetically distinct subgroups influenced to varying degrees by geological history, geographic proximity, habitat connectivity, and human activities. When traits such as growth, maximum size, survival and food consumption have been compared among strains stocked into common environments, researchers have often found differences attributable to genetic causes. Genetic evaluations of ancestry in relation to stocking have revealed a wide range of outcomes from substantial strain mixing and interbreeding to no apparent contribution to resident populations. Genetic principles and data have led to stocking guidelines for conserving within- and among-population genetic variation and avoiding artificial selection in broodstock practices. Future research should include a rangewide assessment of population genetic structure, including assessments of how stocking has affected the spatial structure of wild populations. Genetic data should be used to evaluate retention of genetic diversity in hatchery broodstocks and assess fitness effects of stocked fish on wild populations. Applications of genomic techniques can better inform managers of the genetic basis for differences in performance or adaptive traits and the potential negative consequences of imprudent management practices.