Effect of Temperature on Metabolic Stress and Recovery of Two Argyrosomus Species from Simulated Catch‐and‐release Angling

AbstractCatch‐and‐release (C&R) angling has grown in popularity due to increasing numbers of conservation‐minded anglers and regulations of recreational fisheries. C&R is often assumed to cause low mortality but can cause physiological and physical impairment. Fish metabolism and temperature interact to play a critical role in the biological functioning of fish. Understanding the relationship between temperature, fish metabolism, and physiological impairment is important for effective fisheries management and conservation, particularly for C&R angling in a changing thermal environment. We used respirometry to quantify post‐release metabolic stress and recovery of two popular Namibian angling species (Argyrosomus inodorus and A. coronus) subjected to simulated C&R angling across a range of temperatures. Metabolic stress and recovery time did not differ significantly between warm (A. coronus) and cold‐water (A. inodorus) species at any test temperature. However, several specimens of both species failed to recover physiologically and physically after 10 hours, thereby indicating C&R‐related impairment and potential for mortality. Given the predator‐rich environment of coastal waters in Namibia, best C&R practices are needed to minimise post‐release mortality.