Influence of anatomical hooking depth, capture depth, and venting on mortality of painted comber (Serranus scriba) released by recreational anglers

Immediate (4-5 h) and delayed (10 d) hooking mortality for released fish kept in tanks was evaluated for painted comber (Serranus scriba) taken by the recreational fishery of the Balearic Islands (western Mediterranean). Results showed low rates of immediate (10.8%) and delayed (3.3%) hooking mortality, a total mortality of 14.1%. Anatomical hook location and capture depth were the most significant predictors of mortality; 70.4% of fish caught with a deep location of hook died as a consequence of the damage caused, bleeding, and long unhooking times. Fish caught in depths > 16 m showed evidence of external barotrauma caused by rapid decompression, which increased the probability of death. The most common forms of barotrauma were swimbladder enlargement and stomach inversion. For fish vented with the aid of a hypodermic needle to extract excess gas, mortality was reduced by half. Factors such as surface temperature, fish size, and hook type ("J" hook vs. circle hook) could not explain the mortality of fish released into tanks. Therefore, the results confirm that a practice of catch-and-release ( voluntary or mandatory) for S. scriba needs to be promoted among recreational anglers.