Effectiveness of barotrauma mitigation methods in ice‐angled bluegill and black crappie

Abstract

AbstractBarotrauma can lead to physical injury and physiological disturbance (elevated stress hormones, and depleted energy stores during post‐release struggling) in angled fish. Effectiveness of methods for reducing effects of barotrauma on fish has not been tested on fish subjected to ice‐angling. We examined post‐release behavior and re‐descension of bluegill Lepomis macrochirus and black crappie Pomoxis nigromaculatus. Barotrauma was mitigated for fish either during capture by slow retrieval or following capture by venting or re‐descension with weights, before observation in a behavioral arena or using small acceleration and depth biologgers. Black crappie spent less time in the center of the behavioral arena and were less likely to successfully re‐descend than bluegill. Depth increased over time during the post‐release monitoring period, with control fish less likely to descend to depth as fish for which barotrauma was mitigated. Our results demonstrate species‐specific effects of ice‐angling to inform anglers on the effectiveness of barotrauma mitigation strategies to improve welfare of fish after release.