AUTHORS: Alexander Latzka, Wisconsin Department of Natural Resources; Dan Oele, Wisconsin Department of Natural Resources; Colin Dassow, Wisconsin Department of Natural Resources; Zach Lawson, Wisconsin Department of Natural Resources
ABSTRACT: Muskellunge are the state fish of Wisconsin, are heavily targeted by dedicated anglers, and are relatively large and long-lived. In many Wisconsin lakes, there is little or no natural reproduction, so these fisheries must by supported by stocking. And because budgets are limited, there is a constant need to ensure stocking produces the best bang-for-the-buck. However, evaluating musky stocking events’ impacts on fishery metrics 10-20 years later is inherently difficult, with data accumulating over several decades but at various frequencies across hundreds of lakes, evolving data standards and monitoring protocols, and changing stocking practices. In this talk, we will share our attempt at making the most of these messy and asynchronous—but nonetheless crucially valuable—data to answer a seemingly simple question: where and when is musky stocking successful? We found that stocking events that occurred 3 to 16 years prior to a population survey were most predictive of population outcomes, and used that time window to calculate cumulative stocking rates preceding each population survey. We then used generalized additive mixed models to assess the effects of cumulative stocking rate on musky populations across different lake types and environmental conditions. We are now using these models to recommend updates to muskellunge stocking policies, aimed at ensuring lake-specific objectives are in line with expected stocking performance and prioritizing stocking where it will provide the best returns.
