Fishing-Related Stressors Inhibit Refuge-Seeking Behavior in Released Subadult Great Barracuda

Abstract

Fisheries interactions that result in the capture and release of fish can cause behavioral impairments that increase the risk of postrelease predation. Increased predation risk has been attributed to reduced swimming capabilities; however, the role of refuge (structural shelter) use is still poorly understood. We examined the effect of fishing-related stressors on the ability of subadult Great Barracuda Sphyraena barracuda to attain refuge in an experimental wetland in Eleuthera, The Bahamas. Twenty-two Great Barracuda were either treated as controls with minimum stress, chased to exhaustion, or chased to exhaustion and air exposed for 90 s. Reflex action mortality predictors (RAMP) including ability to maintain equilibrium and bursting response were assessed prior to release at a standardized location. The prop roots of red mangrove Rhizophora mangle provided refuge about 5 m from the release point. Great Barracuda were visually monitored for up to 30 min postrelease to quantify behavior (resting, swimming, directional changes) and the time when refuge was reached. The RAMP scores increased with the degree of stressor, and fish in both fishing-related stressor treatments took significantly longer to reach refuge than control fish, while air exposed fish took significantly longer than fish that were only chased. Prior to reaching refuge, fish exposed to fishing-related stressors spent less time swimming, and changed directions more frequently than control fish, indicating that impaired locomotory capabilities and disorientation inhibited refuge use. The inability to find refuge after an acute stressor such as capture and release fisheries may be an important factor contributing to postrelease mortality for relevant species.

Received September 23, 2013; accepted December 6, 2013

ACKNOWLEDGMENTS

We thank C. Maxey, A. Shultz, and all the staff at Cape Eleuthera Institute and The Island School for supplying facilities and support for this research. This project was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant (S.J.C.), the Canada Research Chairs Program (S.J.C.), the Ontario Ministry of Research and Innovation (S.J.C.), Carleton University, and the University of Massachusetts Amherst.