The National Marine Fisheries Service is mandated by the Magnuson–Stevens Fishery Conservation and Management Act to implement effective annual catch limits and accountability measures to prevent overfishing. These requirements compel further research into alternative fishing practices that could reduce mortality of sharks (class Chondrichthyes) and allow fishers to release unwanted sharks to the water alive, while still effectively catching targeted species. We used hook timers and temperature–depth recorders aboard contracted vessels and participants in the National Marine Fisheries Service’s Shark Research Fishery to collect hooking time and time-on-the-line data for 10 species of sharks that were commonly encountered in the fishery. A subset of standardized fishing sets compared the most popular circle hook and J-hook models. Over 60% of sharks were hooked within 4 h of hook soak time. The fastest to bite the hook was the Atlantic Sharpnose Shark Rhizoprionodon terraenovae and the slowest was the Dusky Shark Carcharhinus obscurus. Shark resilience to time on the longline varied among species, with Sandbar Shark C. plumbeus exhibiting the most resilience and Atlantic Sharpnose Shark the least. Shorter set soak times, approximately 2 h, would still maximize catch, while minimizing at-vessel mortality. The most frequently used circle hook model did not significantly reduce at-vessel mortality over large J-style hooks. The recent circle hook requirement will have little effect for fishers that previously used 12/0 J-hooks, but it may be beneficial by preventing the use of smaller J-hooks that are more likely to cause at-vessel mortality.

中文翻译：

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更少的浸泡时间可以拯救那些在线的人：捕获时间和钓到底部延绳钓的鲨鱼的死亡率

《马格努森-史蒂文斯渔业保护和管理法》授权国家海洋渔业局实施有效的年度捕捞限制和问责措施，以防止过度捕捞。这些要求迫使进一步研究可以降低鲨鱼（软骨鱼纲）死亡率的替代捕捞方法，并允许渔民将不需要的鲨鱼活着释放到水中，同时仍然有效地捕获目标物种。我们使用签约船只上的钩定时器和温度深度记录器以及国家海洋渔业局鲨鱼研究渔业的参与者来收集渔业中常见的 10 种鲨鱼的钩钓时间和上线时间数据。标准化钓鱼套件的一个子集比较了最流行的圆钩和 J 形钩模型。超过 60% 的鲨鱼在鱼钩浸泡时间的 4 小时内被上钩。咬钩最快的是大西洋锐鼻鲨Rhizopriodondon terraenovae和最慢的是Dusky Shark Carcharhinus obscurus。鲨鱼在延绳钓上对时间的恢复能力因物种而异，沙洲鲨鱼C. plumbeus表现出最大的恢复能力，而大西洋锐鼻鲨的恢复能力最低。较短的浸泡时间，大约 2 小时，仍将最大限度地提高捕获量，同时最大限度地减少船上死亡率。与大型 J 型钩相比，最常用的圆形钩模型并没有显着降低血管内死亡率。最近的圆钩要求对以前使用 12/0 J 型钩的渔民几乎没有影响，但通过防止使用更可能导致船上死亡的较小 J 型钩，这可能是有益的。