ANTICIPATING POSSIBLE EFFECTS OF ANGLER EFFORT LEVELS, WINTER SPEARING, AND CLIMATE CHANGE ON LAKE ST. CLAIR MUSKELLUNGE: A MODELING APPROACHByJason Bradley SmithThe current Lake St Clair Great Lakes Muskellunge (Esox masquinongy) (LSCM) fishery is entirely self-sustaining and dominated by a catch and release ethic. Catch rates of LSCM are among the highest of any waterbody, and "trophy fish" are relatively commonplace. The proximity of Lake St Clair to a large number of potential new Muskellunge anglers, angler interest in a winter spear fishery, and warming temperatures associated with climate change pose potential risks to the quality of this fishery. We developed an age-structured equilibrium yield model to predict the likely effects of increased angling effort, establishment of a winter spearing season, or warming temperatures on open-water catch rates of three size classes of LSCM (All fish, Legal fish > 42", Trophy fish > 50"). Our modeling indicated that the current high rate of voluntary release would largely buffer catch rates of all size classes of LSCM from substantial negative effects due to forseeable levels of increased fishing effort. Similarly, our simulation of a winter spearing fishery indicated that only high levels of spearing effort and harvest would negatively affect open-water catch rates to a degree that would be objectionable to anglers. However, the predicted catch rates of Legal and Trophy fish were highly sensitive to modeled reductions in growth due to climate warming. While our model predicts the LSCM fishery to be fairly insensitive to even substantial changes in angling effort and spearing harvest, possible effects of warming, which are difficult for fisheries managers to mitigate, could be significant.
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