Discard Mortality of Red Snapper Released with Descender Devices in the U.S. South Atlantic

Abstract

Fishery regulations mandate the release of many caught fish, elevating the importance of having accurate estimates of discard mortality. Red Snapper Lutjanus campechanus are overfished and undergoing overfishing in the southeast U.S. Atlantic, in part due to the high number of releases that die from discard mortality. We used acoustic telemetry to track the fine‐scale movements of hook‐and‐line‐caught Red Snapper released with descender devices at a hard‐bottom site off North Carolina, USA. Movement characteristics of known‐fate (live and dead) Red Snapper were used to infer fates of other individuals, from which we generated a proportional mortality estimate of 0.08 (95% CI = 0.00–0.17) for successfully descended Red Snapper with no hook trauma. This best‐case mortality estimate was then used in a simulation to estimate overall Red Snapper discard mortality for the recreational fishery in the southeast U.S. Atlantic based on hooking location and a depth of approximately 37 m. For this fishery, we estimated the median proportional rate of discard mortality to be 0.13 (2.5% and 97.5% percentiles = 0.10, 0.17) if all released individuals were descended. This estimate is lower than the discard mortality values (˜0.2–0.3 for the recreational fishery) used in the current Red Snapper stock assessment, but it is likely not reflective of the current reality given that descender use is not 100% in this region; this estimate is also depth specific. Increased use of descender devices will reduce discard mortality for Red Snapper, enhancing efforts to rebuild this stock.