Sport fish home range responses to a littoral coarse woody habitat addition in a north-temperate lake

Behavioural responses of fishes to littoral zone habitat enhancements are relatively understudied in diverse fish communities but are critical for understanding overall fish community responses. To advance knowledge on effects of coarse woody habitat (CWH) littoral zone enhancements, we initiated a long-term study on Sanford Lake, Vilas County, Wisconsin, where 160 trees were added to the littoral zone of the lake in 2018. We tested for short-term home range responses in muskellunge (Esox masquinongy), smallmouth bass (Micropterus dolomieu) and walleye (Sander vitreus) to this CWH addition. We used radio telemetry data collected premanipulation (2017) and postmanipulation (2018 and 2019) to construct annual home range estimates for each species. Limited kernel density (LKD) estimates, which partially exclude terrestrial areas, were used for estimating 50% and 95% home ranges. Over the course of the three years, average home ranges for each study species increased suggesting a behavioural response to the CWH addition. Muskellunge had the greatest home range estimate increase, followed by smallmouth bass and then walleye. Muskellunge and smallmouth bass had similar home ranges, which were larger than walleye home ranges. Increased home ranges across species could be a searching or deviation from premanipulation equilibrium home range response as a result of the CWH serving as a prey fish refuge, which may make them relatively inaccessible to predators. Our results suggest that fish behavioural responses to CWH additions may be species-specific and should be taken into consideration prior to implementing littoral habitat enhancements in diverse fish communities.