Development, Implementation and Evaluation of a Genetic Broodstock Management Plan

Conserving genetic resources within hatchery propagation programs is a focal concern for sustainable fisheries management programs. The Wisconsin Department of Natural Resources muskellunge Esox masquinongy propagation program recently implemented comprehensive guidelines to conserve genetic diversity at the hatchery- and stock-levels. Specific goals of this program included conservation of among-population genetic diversity and development of protocols to conserve within-population diversity. Through a series of research projects, muskellunge stock structure was delineated, regional broodstocks selected, and hatchery guidelines developed. Hatchery guidelines included mating and pond-mixing strategies, and prescription of an appropriate number of broodfish required to reach desired effective population sizes (N_e) and maintain ≥ 95% of alleles observed within the regional broodstock. We critically evaluated the proposed changes to identify potential genetic bottlenecks (broodstock, gamete contribution, fry and fingerling life stages) and areas for improvement. One of two hatcheries met our goal of N_e = 350 over a single generation (7 years), and both hatcheries made large improvements over historical techniques related to broodstock collection, spawning techniques, maintaining allelic diversity and frequencies, and regional fish distribution (i.e., consideration of genetic structure). Unequal contributions from female family groups and insufficient broodstock collection represent areas of future improvements.