Impact of catch and release on the welfare of bronze seabream Pachymetopon grande in the South African marine shore-based fishery

Abstract

The practice of catch-and-release (C&R) angling is increasingly being integrated into recreational fisheries as a conservation strategy to promote sustainability. However, C&R can still have lethal or sublethal effects owing to various stressors involved in the act of angling. Using a modified rapid-assessment approach, this study evaluated the potential impact of C&R on the health and short-term survival of bronze seabream Pachymetopon grande in the South African marine shore-based recreational fishery. The air-exposure period was found to be a driver of increased physical impairment, with significantly higher reflex action mortality predictor scores for fish exposed for 70 s or 200 s, whereas the low air-exposure time of 10 s, associated with globally recognised best practices, was least impactful. Using a delayed blood sampling technique, fight time was positively linked to increased blood lactate concentrations, which concurs with other findings and highlights the need to reduce the fight time where possible to limit stress from physical exertion during C&R events. Though mortality was low across all treatments (<4%), air-exposure-driven reflex impairment would likely contribute to increased predation risk if the fish were released directly back into the sea. Handling recommendations include well-established methods that mitigate against hooking injury and reduce the handling and air-exposure times. The incorporation of a species-specific delay in blood sampling shows promise for improving the reliability of physiological markers for evaluating stress responses to C&R in wild fishes, but further refinements are required for this new technique.