Bycatch remains one of the most important issues in the world's fisheries so its estimation and reporting have been highlighted in many international, regional and jurisdictional guidelines and policies. This paper describes a simple methodology to estimate jurisdictional discards, using Australia's first national bycatch report as a case study. The methodology involves: (a) identifying annual landings for all fisheries and methods; (b) deriving retained:discard ratios for each; (c) where ratios are lacking, using substitute ratios from similar fisheries; (d) applying the ratios from (b) and (c) to the data from (a) to obtain totals; and (e) scoring the quality of the discard information using the US Tier Classification System weighted by estimated discard levels. The results for Australia revealed that, during the last decade, commercial fisheries annually discarded 42.5% of what was caught (87,983t). 70% came from just eight fisheries/methods with 30% coming from the other 299. The Queensland East Coast Prawn Trawl fishery contributed 28.5% of the national total. The quality of discard information was reasonable across most jurisdictions, with a national score of 59.1%. The best quality data came from the Commonwealth due to its observer and (more recent) Electronic Monitoring programmes. Those data also showed that fishers’ logbook information under‐estimated levels of discards (determined from observer data) by 89.7%. This paper provides: (a) the means to develop benchmarks in bycatch management and estimation against which jurisdictions can be compared and performances tracked; and (b) for Australia, priority areas for management intervention to reduce discarding and improve its monitoring.

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兼捕已知：关于渔业丢弃物的管辖权报告的方法–以澳大利亚为例

兼捕仍然是世界渔业中最重要的问题之一，因此在许多国际，区域和司法管辖区的准则和政策中都强调了它的估计和报告。本文以澳大利亚的首份国家兼捕报告为例，介绍了一种简单的方法来估算司法管辖区的丢弃物。该方法包括：（a）确定所有渔业和方法的年度登陆量；（b）推导各自的保留：丢弃率；（c）在缺乏比例的情况下，使用类似渔业的替代比例；（d）将（b）和（c）的比率应用于（a）的数据，以得出总数；（e）使用美国Tier分类系统对估计的丢弃水平加权的评分信息质量。澳大利亚的结果表明，在过去十年中，商业渔业每年丢弃的渔获量（87,983吨）占其的42.5％。70％来自仅八个渔业/方法，另外30％来自其他299种。昆士兰州东海岸对虾拖网渔业占全国总数的28.5％。在大多数辖区中，丢弃信息的质量是合理的，全国得分为59.1％。由于英联邦的观察员和（最近的）电子监测计划，其质量最高的数据来自英联邦。这些数据还表明，渔民的日志信息低估了丢弃物水平（由观察者数据确定），降低了89.7％。本文提供：（a）在兼捕物管理和评估中制定基准的方法，可以将其与管辖区进行比较和跟踪绩效；（b）对于澳大利亚，