Spatial ecology and thermal preferences of muskellunge within a Midwest impoundment

Muskellunge are a valuable sportfish species which has been stocked throughout North America. Stocking is a strategy to generate angling opportunities by introducing species to waterbodies that otherwise would not have contained the fish, such as impoundments and reservoirs. Therefore, understanding the ways fish interact with different waterbodies is critical for managers to understand. To that end, we utilized a year-long passive telemetry study with muskellunge in a reservoir known for its muskellunge angling. Additionally, we employed temperature loggers to track lake temperatures. We found that smaller female muskellunge were more resident at sites compared to similar-sized males, although fish did not exhibit site-specific preferences. We also found that fish moved high distances over the course of the year without time-specific differences. Furthermore, we found evidence that muskellunge was selected for thermal refuges in the reservoir; however, in summer, when water temperatures were elevated, fish inhabited water, which has been shown to increase incidental mortality. The results of this study indicate a need for muskellunge managers, especially in reservoirs, to consider water temperature in angling regulations. Additionally, our results highlight a need for adding habitat structure in reservoirs and altering stocking densities of fish. Collectively, these results will help inform managers on muskellunge spatial interactions within a reservoir and achieve management goals.