Effects of Harvest Mortality on Muskellunge Size Structure in Wisconsin's Ceded Territory

Muskellunge management is often aimed at producing large trophy individuals.  However, the muskellunge is a long-lived species that occurs naturally at low population densities, which makes it susceptible to the effects of harvest mortality.  Muskellunge populations within Wisconsin's ceded territory are exposed to both angling and spearing fisheries.  Our objective is to determine the extent that harvest mortality affects muskellunge population size structure in Wisconsin’s ceded territory.  We developed a simulation model to predict the effect of varying levels of harvest mortality from angling and spearing fisheries on size structure of muskellunge populations producing large-, medium-, and small-bodied fish.  We found that muskellunge size structure decreased as harvest mortality increased, and identified specific combinations of angling and spearing harvest mortality that prevented trophy muskellunge populations from producing large individuals.  Some levels of harvest mortality are detrimental to muskellunge size structure, so changes may need to be made to current muskellunge management in Wisconsin.