Effect of temperature on metabolic stress and recovery of two <i>Argyrosomus</i> species from simulated catch‐and‐release angling

Abstract

Abstract Catch‐and‐release (C&amp;R) angling has grown in popularity due to increasing numbers of conservation‐minded anglers and regulations of recreational fisheries. C&amp;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&amp;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&amp;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&amp;R‐related impairment and potential for mortality. Given the predator‐rich environment of coastal waters in Namibia, best C&amp;R practices are needed to minimise post‐release mortality.