Muskellunge Esox masquinongy is a prized sport fish throughout much of North America. Due to its popularity among anglers and limited natural recruitment in reservoirs, Muskellunge are commonly stocked to maintain populations. Yet, little is known about post-stocking behavior and survival in reservoirs. We used radio telemetry to evaluate behavior and survival of spring-stocked yearling Muskellunge in two Iowa reservoirs that differed in habitat availability (Big Creek = limited habitat, Brushy Creek = abundant habitat). Hatchery-reared Muskellunge were implanted with radio transmitters (n=15-16 per lake/year; 61 fish total), stocked in both lakes during May 2017 and 2018, tracked daily for one week, every other day for the second week, and then weekly until December. Telemetry data were used to evaluate depth and vegetation use, selection of littoral substrate and coarse woody habitat (CWH) complexities, movement, home ranges, and survival. Muskellunge depth use generally increased with time post-stocking and was greater in Brushy Creek than Big Creek. Movement rates were greatest during the first week post-stocking and declined thereafter, with greater rates and home ranges in Big Creek. Muskellunge in both systems selected for fine substrates while avoiding coarse substrates. Brushy Creek Muskellunge were more commonly associated with CWH and aquatic vegetation compared to Big Creek. Muskellunge in Big Creek selected for complex CWH while those in Brushy Creek used CWH classes in proportion to their availability. Cormack- Jolly-Seber daily apparent survival estimates were lowest for the first four days post-stocking and ranged from 0.59 to 0.99, after which survival increased from May to September before declining in October and November. Results of this study provide greater understanding of post-stocking success of yearling Muskellunge and suggest Muskellunge behavior and survival is dependent on habitat complexity, with weaker habitat selection but higher survival in complex systems.

Muskellunge Esox masquinongy is the largest esocid and a prized sport fish throughout much of North America. By the early 1900s, large declines in native Muskellunge populations had occurred due to overexploitation and loss of quality nursery and spawning habitat (Dombeck et al. 1984; Farrell et al. 2007; Kapuscinski et al. 2007). Today, Muskellunge are popular among many anglers due to their large size and angling difficulty (Casselman et al. 1999; Farrell et al. 2007). For example, a 2012 report estimated 25% of Wisconsin anglers targeted Muskellunge, representing approximately 5.3 million angler–days and $425 million in annual expenditures (Simonson 2012). Consequently, many agencies currently stock Muskellunge within and outside their native range to maintain, enhance, and expand populations and meet angler demand (Kerr 2011).