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.

中文翻译：

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丢弃在美国南大西洋使用 Descender 设备释放的红鲷鱼的死亡率

渔业法规要求释放许多捕获的鱼，从而提高准确估计丢弃死亡率的重要性。红鲷鱼Lutjanus campechanus在美国东南部大西洋被过度捕捞和过度捕捞，部分原因是因丢弃死亡率而死亡的大量释放。我们使用声学遥测技术来跟踪在美国北卡罗来纳州附近的硬底地点随下降装置释放的钩线捕获的红鲷鱼的精细运动。已知命运（活的和死的）红鲷鱼的运动特征被用来推断其他个体的命运，我们从中生成了 0.08 (95% CI = 0.00–0.17) 成功下降的红鲷鱼的比例死亡率估计值，没有钩伤. 然后在模拟中使用此最佳情况死亡率估计值，以根据上钩位置和大约 37 m 的深度估计美国大西洋东南部休闲渔业的总体红鲷鱼丢弃死亡率。对于这个渔业，如果所有被释放的个体都下降，我们估计丢弃死亡率的中位数比例为 0.13（2.5% 和 97.5% 的百分位数 = 0.10, 0.17）。该估计值低于当前红鲷鱼种群评估中使用的丢弃死亡率值（休闲渔业约为 0.2–0.3），但鉴于该地区的下降使用率不是 100%，因此可能无法反映当前的现实；这个估计也是特定于深度的。增加使用下降装置将降低红鲷鱼的丢弃死亡率，从而加强重建该种群的努力。3 用于休闲渔业）在当前的红鲷鱼种群评估中使用，但鉴于该地区的下降使用率不是 100%，这可能无法反映当前的现实；这个估计也是特定于深度的。增加使用下降装置将降低红鲷鱼的丢弃死亡率，从而加强重建该种群的努力。3 用于休闲渔业）在当前的红鲷鱼种群评估中使用，但鉴于该地区的下降使用率不是 100%，这可能无法反映当前的现实；这个估计也是特定于深度的。增加使用下降装置将降低红鲷鱼的丢弃死亡率，从而加强重建该种群的努力。