Bycatch in pelagic longline fisheries threatens the viability of some seabird populations and reduces fishing efficiency. The mass of a branchline fishing weight and its distance from the hook significantly explain seabird catch risk during setting and hauling. We surveyed Hawaii tuna longline fishers to obtain their perspectives on the practicality, safety and economic viability of alternative designs which place weights adjacent to hooks instead of conventional designs with weighted swivels attached 0.6 m from the hook. We conducted experimental fishing to explore the commercial viability of a combination weighted swivel attached to the eye of the hook. We used a Bayesian random effects meta-analytic regression modeling approach to estimate pooled expected species-specific log relative risk of capture on conventional, as opposed to experimental, branchlines. There were significant decreases in catch rates on experimental branchlines of 54% (95% highest posterior density interval [HDI]: 34.3 to 73.8) for retained species and 28% (95% HDI: −7.5 to 93.3) for discarded species. For about 10% of experimental weighted hooks, the point of the hook tangled on the swivel, likely contributing to lower catch rates and making it more difficult for crew to coil branchlines. We identify additional possible factors explaining why the experimental gear reduced catch rates. The study demonstrates the benefits of stakeholder scoping to determine bycatch mitigation options with the highest promise for practicality, economic viability and safety, as well as benefits of conducting a pilot study to assess commercial viability to determine if a full experiment to assess bycatch mitigation efficacy is warranted.

中文翻译：

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替代设计的商业可行性在钩上放置远洋延绳钓线重量以减少海鸟兼捕

远洋延绳钓渔业中的副渔获物威胁到一些海鸟种群的生存能力并降低捕捞效率。支线捕鱼重量的质量及其与鱼钩的距离显着解释了在设置和拖运过程中捕获海鸟的风险。我们对夏威夷金枪鱼延绳钓渔民进行了调查，以了解他们对替代设计的实用性、安全性和经济可行性的看法，这些设计将重物放置在钩子附近，而不是将加重的转环连接在离钩子 0.6 m 处的传统设计。我们进行了实验捕鱼，以探索连接到钩眼的组合加权旋转接头的商业可行性。我们使用贝叶斯随机效应元分析回归建模方法来估计汇总的预期物种特异性对数相对捕获风险，而不是实验，支线。实验分支线的捕获率显着下降，保留物种为 54%（95% 最高后密度区间 [HDI]：34.3 至 73.8），丢弃物种为 28%（95% HDI：-7.5 至 93.3）。对于大约 10% 的实验加重吊钩，吊钩的尖端在旋转接头上缠结，这可能导致捕获率降低，并使船员更难盘绕支线。我们确定了其他可能的因素，解释了为什么实验渔具降低了捕获率。该研究证明了利益相关者范围界定对实用性、经济可行性和安全性具有最高承诺的利益相关者确定兼捕缓解方案的好处，以及进行试点研究以评估商业可行性以确定评估兼捕缓解效力的完整实验的好处保证。