The incidental capture by marine fisheries as bycatch poses a global threat to pelagic sharks and rays. In large, industrialized fisheries that often operate in areas beyond national jurisdiction, at least 22 threatened species of pelagic elasmobranchs are caught as bycatch, representing the majority of megafauna bycatch in tuna fisheries. Here, we investigate (1) the efficacy of the current policies of the five tuna-related Regional Fisheries Management Organizations (tRFMOs) in mitigating elasmobranch bycatch, (2) data needed to better assess the amount and impact of elasmobranch bycatch and (3) the research necessary for the adoption of new policies. We found that tRFMOs have adopted 34 active policies that address pelagic elasmobranch bycatch. However, most policies (~76%, n = 26) are unlikely to avoid or minimize elasmobranch bycatch. Instead, most policies focus on mitigating post-capture mortality via remediation and requiring or encouraging research and data collection. Despite the emphasis on research mandates, we find that the existence of research was not related to policy adoption, suggesting that lack of research has not historically prohibited policymaking. Overall, we suggest that current research and data transparency, though perhaps not necessary for policy adoption, are not sufficient to adequately evaluate the population-level impacts of bycatch on many elasmobranch species in tRFMO-managed fisheries. Given these results, we recommend a precautionary approach that involves reforms in tRFMO voting processes to facilitate the adoption of binding requirements for elasmobranch catch limits, bycatch avoidance, pre- and post-capture handling and release modifications and protection of areas important to threatened pelagic elasmobranchs.

中文翻译：

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公海金枪鱼渔业中海洋鲨鱼和鳐鱼的政策和透明度差距

海洋渔业作为兼捕物的偶然捕获对远洋鲨鱼和鳐鱼构成了全球威胁。在通常在国家管辖范围以外地区作业的大型工业化渔业中，至少有 22 种受威胁的远洋软骨鱼类作为兼捕物被捕获，占金枪鱼渔业中巨型动物兼捕物的大部分。在这里，我们调查 (1) 五个与金枪鱼相关的区域渔业管理组织 (tRFMO) 的现行政策在减少软骨鱼类兼捕方面的效力，(2) 更好地评估软骨鱼类兼捕的数量和影响所需的数据，以及 (3)采用新政策所必需的研究。我们发现 tRFMO 采取了 34 项积极政策来解决远洋板鳃类兼捕问题。然而，大多数政策（~76%，n = 26) 不太可能避免或尽量减少软骨鳃鱼的误捕。相反，大多数政策侧重于通过补救和要求或鼓励研究和数据收集来降低捕获后死亡率。尽管强调研究任务，但我们发现研究的存在与政策采用无关，这表明缺乏研究在历史上并未阻碍政策制定。总体而言，我们建议当前的研究和数据透明度虽然可能不是政策采用所必需的，但不足以充分评估兼捕对 tRFMO 管理的渔业中许多软骨鱼类的种群水平影响。鉴于这些结果，我们建议采取一种预防方法，包括改革 tRFMO 投票流程，以促进采用具有约束力的软骨鱼类捕捞限制要求，