Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

Evaluating Muskellunge Growth Potential in Northwestern Wisconsin Lakes without Age Information

Timothy P. Parks, Jeffrey M. Kampa, Gene R. Hatzenbeler, and Martin J. Jennings

doi: https://doi.org/10.47886/9781934874462.ch44

Abstract.—Meaningful growth potential information is a critical component of determining minimum length regulations for harvesting Muskellunge Esox masquinongy. The use of tags and recapture-based statistical methods allow managers to assess growth for species like Muskellunge without having to sacrifice fish to obtain traditional size-at-age information from hard-bony structures. The purpose of our study was to determine the growth potential of tagged Muskellunge without age data and to demonstrate two recapture-based statistical methods we used to estimate asymptotic length. Muskellunge asymptotic length was estimated for seven northwestern Wisconsin Lakes using the Ford–Walford and Fabens methods. Using the Ford–Walford method, overall mean asymptotic length of Muskellunge was estimated to be 41.6 in (1 in = 2.54 cm; range = 37.2–49.1 in) and was larger for females (range = 30.3–47.5 in) than for males (range = 36.6–40.4 in). Similarly, using the Fabens method we estimated a mean asymptotic length of 42.3 in (range = 30.6–49.1 in) and estimated asymptotic length was greater for females (range = 28.6–51.3 in) than for males (range = 35.2–40.3 in). Both methods produced fairly similar estimates but differed in estimated precision and potential bias when compared to maximum observed total length. Nonetheless, both methods revealed insights about Muskellunge growth potential without sacrificing fish and both methods should be considered as potential tools for biologists needing to better understand Muskellunge growth.