The biological consequences of catch-and-release (C&R) angling revolve around interactions between the physiological and behavioural responses of the captured fish and ecological conditions such as the presence of opportunistic predators. Here, we explored the consequences of C&R on adult permit (Trachinotus falcatus), including assessments of depredation rates, their physiological and reflex responses prior to release, post-release behaviour, and post-release predation in diverse habitats in the Florida Keys, USA. We found pre-capture depredation rates were highly variable amongst habitat types, ranging from zero on shallow water flats, to 35.3% and 90.1% on specific reef and shipwreck locations, respectively. Observed predators were all large sharks. Importantly, one of the high predation sites is an important permit spawning location, thus C&R fishing in that locale may be a conservation concern. Physiological stress responses (blood lactate, glucose, pH) and reflex tests indicated that permit were relatively robust to routine angling (fight durations of 1 to 12 min) and handling (air exposure up to 2 min). Short duration post-release tracking using tri-axial acceleration biologgers identified no differences in swimming activity for fish that were kept in water versus those held in the air for 2 min to simulate an admiration period. While this study indicates that permit are relatively robust to C&R angling in terms of stress responses and behavioural impairment, high densities of opportunistic predators at certain fishing locations can result in high rates of pre-capture depredation independent of the state of the animal. Permit angling in locations with high predator densities is a potential conservation issue, especially if specific locations represent important pre-spawning aggregation sites for fish populations that may be more vulnerable to predation and thus depredation. Current C&R best practices (i.e., limiting fight times and air exposure) may not be adequate to ensure permit survival at high predator density sites. Angling-related depredation is often cryptic, yet is a growing conservation concern in many fisheries – we developed and applied a novel framework for identifying cryptic depredation that may be applicable across fisheries.

Best practices, Depredation, Marine, Predation, Recreational fishing
Journal of Experimental Marine Biology and Ecology
Department of Biology

Holder, P.E. (Peter E.), Griffin, L.P. (Lucas P.), Adams, A.J. (Aaron J.), Danylchuk, A.J. (Andy J.), Cooke, S.J, & Brownscombe, J.W. (Jacob W.). (2020). Stress, predators, and survival: Exploring permit (Trachinotus falcatus) catch-and-release fishing mortality in the Florida Keys. Journal of Experimental Marine Biology and Ecology, 524. doi:10.1016/j.jembe.2019.151289