Abstract Gillnets are very common in small-scale fisheries. However, data obtained using gillnets are biased because of their size selectivity, making accurate estimation of mortality difficult. This study applied various methods to estimate total, natural, and fishing mortality, using data for Lane Snapper (Lutjanus synagris) collected in Tela, Honduras. Total mortality was estimated using a catch-curve analysis with and without accounting for size-selectivity using fitted selectivity curves, the Chapman and Robson method, and Heincke’s method. Gillnet selectivity of Lane Snapper was best characterized by a skewed normal selectivity curve. The catch-curve method in the absence of correction for gear selectivity produced greater total mortality estimates than the Chapman and Robson and Heincke’s methods, with substantial variation among the three methods. Natural mortality estimates were consistent among five methods: Lorenzen, Peterson and Wroblewski, Sekharan, “FishLife” R package and Pauly’s method. Consequently, variation among fishing mortality estimates was primarily the result of variation in estimates of total mortality. Our results suggest that accounting for gear selectivity is critically important when assessing and managing small-scale fisheries.

中文翻译：

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为评估小型渔业而估算死亡率：洪都拉斯的莱鲷 (Lutjanus synagris)

摘要 刺网在小型渔业中很常见。然而，使用刺网获得的数据由于其尺寸选择性而存在偏差，这使得准确估计死亡率变得困难。本研究使用在洪都拉斯特拉 (Tela) 收集的 Lane Snapper (Lutjanus synagris) 数据，应用各种方法来估计总死亡率、自然死亡率和捕捞死亡率。使用捕获曲线分析估计总死亡率，使用拟合选择性曲线、Chapman 和 Robson 方法以及 Heincke 方法在考虑和不考虑大小选择性的情况下进行。Lane Snapper 的 Gillnet 选择性的最佳特征是偏斜的正态选择性曲线。与查普曼、罗布森和海因克的方法相比，在没有对渔具选择性进行校正的情况下，捕获曲线方法产生了更高的总死亡率估计值，三种方法之间存在较大差异。自然死亡率估计在五种方法中是一致的：Lorenzen、Peterson 和 Wroblewski、Sekharan、“FishLife”R 包和保利的方法。因此，捕捞死亡率估计数之间的差异主要是总死亡率估计数变化的结果。我们的结果表明，在评估和管理小规模渔业时，考虑到渔具选择性至关重要。