Genetic Information Used to Guide Muskellunge Management in Minnesota

The Minnesota Department of Natural Resources has increasingly used genetic information to help manage one of the premier muskellunge fisheries in the U.S.  The initial impetus to consider genetics was the poor growth of a strain being stocked statewide. A common-garden experiment demonstrated a likely genetic component to this poor growth and a new broodstock was developed. Genetic markers were able to track persisting ancestry from the poor-growing strain and demonstrate that its descendents were not attaining large sizes. In one lake, tagging and genetics were combined to target descendents for removal to determine if size structure could be improved. The study also showed that native genetics persist in several lakes despite years of stocking. Another study examined the current muskellunge stocking program. Reductions in genetic diversity compared with the source population indicated likely fragmentation and bottleneck effects in brood and stocked lakes. Genetic markers are also being used as part of mark-recapture estimates of population size. The ability to extract DNA from scales has allowed anglers to participate in non-lethal collection of recapture samples. Individual fish were successfully identified in initial attempts to use this approach but poor angler returns limited power to precisely estimate population sizes.