Yearling Muskellunge Poststocking Behavior and Survival in Two Central Iowa Reservoirs with Contrasting Habitat Availability

Abstract

AbstractMuskellunge Esox masquinongy is a prized sport fish throughout much of North America. Due to the species’ popularity among anglers and limited natural recruitment in reservoirs, Muskellunge are commonly stocked to maintain populations. However, little is known about their poststocking behavior and survival in reservoirs. We used radiotelemetry to evaluate behavior and survival of spring‐stocked yearling Muskellunge in two Iowa reservoirs that differed in habitat availability (Big Creek Lake: limited habitat; Brushy Creek Lake: abundant habitat). Hatchery‐reared Muskellunge were implanted with radio transmitters (n = 15–16 fish·lake−1·year−1; 61 fish total) and stocked in both lakes during May 2017 and 2018; fish were tracked daily for 1 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 poststocking and was greater in Brushy Creek Lake than in Big Creek Lake. Movement rates were greatest during the first week poststocking and declined thereafter, with greater rates and home ranges in Big Creek Lake. Muskellunge in both systems selected for fine substrates while avoiding coarse substrates. Muskellunge in Brushy Creek Lake were more commonly associated with CWH and aquatic vegetation compared to those in Big Creek Lake. Muskellunge in Big Creek Lake selected for complex CWH, while those in Brushy Creek Lake used CWH classes in proportion to their availability. Cormack–Jolly–Seber daily apparent survival estimates were lowest for the first 4 d poststocking 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 a greater understanding of the poststocking success of yearling Muskellunge and suggest that Muskellunge behavior and survival are dependent on habitat complexity, with weaker habitat selection but higher survival in complex systems.