Bycatch continues to be a challenge to sustainable fisheries management (The term “bycatch” in this paper covers discards and does not include retained incidental catch). Bycatch estimates can inform stock status determinations by improving understanding of fishing mortality, and help managers monitor the effectiveness of regulations. Assessments of the quality of bycatch estimation programs and procedures are necessary to evaluate the precision and limitations of their results over time. NOAA Fisheries experts used a “Tier Classification System” (TCS) to compare the quality of fish bycatch data and estimation methods for U.S. commercial fisheries in 2005 and 2015. The TCS included criteria related to data adequacy and analytical approaches. A comparison of U.S. fishery tier scores demonstrated that most fisheries were classified into higher tiers in 2015 compared to 2005 due to factors including improved sampling design. In addition, this comparison identified region-specific trends (e.g., mostly improvements occurred for Alaska fisheries with more mixed results for Greater Atlantic fisheries). The improvements in bycatch data quality and estimation methods in the United States are a result of financial investments in observer programs by NOAA Fisheries and industry partners, as well as effective conservation measures implemented by regional fishery management councils and NOAA Fisheries. The TCS was also used to assess bycatch data and estimation methods in all of Australia’s fishery jurisdictions for the decade 2010–19, illustrating the international applicability of the method. Overall, Australian state fisheries scored lower than federally managed fisheries in both the United States and Australia, reflecting the fact that the latter fisheries tend to be larger (and more valuable) than those in state jurisdictions, with a larger investment in observer programs. A comparison of tier scores and estimates of discards by fishery may provide a useful input for decision-making processes regarding allocation of resources to improve bycatch monitoring.

兼捕仍然是可持续渔业管理的挑战（本文中的“兼捕”一词涵盖丢弃物，不包括保留的附带渔获物）。兼捕估计可以通过提高对捕捞死亡率的了解来确定种群状况，并帮助管理人员监测法规的有效性。必须对兼捕估计计划和程序的质量进行评估，以随着时间的推移评估其结果的精确性和局限性。NOAA 渔业专家使用“层级分类系统”(TCS) 来比较 2005 年和 2015 年美国商业渔业鱼类兼捕数据的质量和估计方法。 TCS 包括与数据充分性和分析方法相关的标准。美国的比较 渔业层级得分表明，与 2005 年相比，2015 年大多数渔业被划分为更高的层级，原因包括改进的抽样设计。此外，这种比较确定了特定区域的趋势（例如，阿拉斯加渔业的改善主要发生在大大西洋渔业的结果更加复杂）。美国副渔获物数据质量和估计方法的改进是 NOAA 渔业和行业合作伙伴对观察员计划的财政投资以及区域渔业管理委员会和 NOAA 渔业实施的有效保护措施的结果。TCS 还用于评估 2010-19 十年间澳大利亚所有渔业管辖区的兼捕数据和估算方法，说明该方法的国际适用性。全面的，在美国和澳大利亚，澳大利亚州渔业的得分低于联邦管理的渔业，反映出后者的渔业往往比州管辖范围内的渔业规模更大（也更有价值），对观察员计划的投资更大。层级得分和渔业丢弃物估计值的比较可为有关资源分配的决策过程提供有用的输入，以改进兼捕监测。