Abstract

In some fisheries, releases are a high percentage of total catch. Recent tagging data of marine fishes have revealed that recapture of the same individual multiple times occurs frequently. We investigated the magnitude of this phenomenon and its effect on survival using previously collected mark-recapture data of four reef-associated species. We used Cox proportional hazard regression models to examine whether survival varied with release number. For three of four species, survival was significantly higher after the second, third, and/or fourth release as compared to the first release, perhaps resulting from selection for robust individuals. Repetitive recapture implies that the estimated number of unique released fish is biased. Increased survival following later releases as compared to the initial release suggests that the number of dead discards may be similarly overestimated. We analysed the sensitivity of stock assessment results to reduced estimates of dead discards using two of our species that had recently been assessed. We found that reduced estimates of dead discards had a modest effect on assessment results but could nonetheless affect the perception of fishery status. Our findings highlight the need to revise current practices for estimating live and dead discards, either internal or external to stock assessment models.

中文翻译：

---

重复捕捞海水鱼类：对估计释放数量和死亡率的影响

摘要

在某些渔业中，释放量占总捕捞量的很大百分比。最近的海水鱼类标签数据表明，多次捕获同一个人经常发生。我们使用先前收集的四个与珊瑚礁有关的物种的标记捕获数据，研究了这种现象的严重性及其对生存的影响。我们使用Cox比例风险回归模型来检查生存率是否随释放数量而变化。对于四个物种中的三个，第二，第三和/或第四次释放后的存活率比第一次释放高得多，这可能是由于选择了健壮的个体所致。重复捕捞意味着释放的独特鱼类的估计数量存在偏差。与最初的释放相比，后来的释放后存活率增加表明死者丢弃物的数量可能被高估了。我们使用最近评估过的两个物种，分析了种群评估结果对减少死角估计的敏感性。我们发现减少的死角估计数对评估结果影响不大，但仍可能影响对渔业状况的看法。我们的发现强调，有必要修订当前评估存货评估模型内部或外部的活和死丢弃物的做法。我们发现减少的死角估计数对评估结果影响不大，但仍可能影响对渔业状况的看法。我们的发现强调，有必要修订当前评估存货评估模型内部或外部的活和死丢弃物的做法。我们发现减少的死角估计数对评估结果影响不大，但仍可能影响对渔业状况的看法。我们的发现强调，有必要修订当前评估存货评估模型内部或外部的活和死丢弃物的做法。