Abstract Bycatch of seabirds in longline fisheries includes mortalities and live captures (mainly during hauling). Excluding outliers, the latter accounts for 5–70% (mean 40.4%) of all bycaught birds in demersal, and 3–23% (mean 10.7%) in pelagic longline fisheries. The proportion that later die from injuries is unknown, and this cryptic mortality complicates efforts to quantify fisheries impacts. Over a 26-year period at South Georgia, foul-hooking indices - birds with embedded hooks or entangled among tens of thousands checked at the colony - were broadly similar in wandering albatrosses Diomedea exulans and giant petrels Macronectes spp., an order of magnitude lower in black-browed albatrosses Thalassarche melanophris and nil in two other albatross species. This likely reflected differing degrees of overlap with fisheries and interaction with gear during hauling. Indices peaked in the early-mid 2000s, then declined, broadly corresponding with changing fishing practices, including the lagged effect of a seasonal fisheries-closure, introduction of a new fishing system, reduced effort in some demersal fisheries and general improvements in bycatch mitigation. Foul-hooking indices at colonies can therefore reflect relative risk for different species over time, and be a useful adjunct to vessel-based monitoring of live-capture rates. Taking into account age and status when reported, and annual survival probabilities, subsequent survival of live-caught and released wandering albatrosses was around 40% of that expected for the wider population. This has major implications for ecological risk assessments that seek to determine the impacts of fisheries on seabirds, as most do not currently consider deleterious impacts of live capture.

中文翻译：

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渔业中信天翁和海燕活体捕获率的变化、释放后的存活率和对管理的影响

摘要 延绳钓渔业中的海鸟兼捕包括死亡和活捕（主要是在拖运期间）。排除异常值，后者占底层所有兼捕鸟类的 5-70%（平均 40.4%），在远洋延绳钓渔业中占 3-23%（平均 10.7%）。后来死于伤害的比例是未知的，这种神秘的死亡率使量化渔业影响的工作复杂化。在南乔治亚岛 26 年的时间里，在游荡的信天翁 Diomedea exulans 和巨海燕 Macronectes spp. 中，带有嵌入钩子的鸟类或在该殖民地检查的数以万计的鸟类中纠缠的犯规指数大致相似，低一个数量级在黑眉信天翁 Thalassarche melanophris 和另外两个信天翁物种中为零。这可能反映了在拖运过程中与渔业的不同程度重叠以及与渔具的相互作用。指数在 2000 年代初中期达到顶峰，然后下降，这与捕捞方法的变化大体一致，包括季节性渔业关闭的滞后效应、新捕捞系统的引入、一些底层渔业的努力减少以及兼捕减缓的总体改善。因此，殖民地的污秽指数可以反映不同物种随时间变化的相对风险，并且可以作为基于船只的实时捕获率监测的有用辅助手段。考虑到报告时的年龄和状态，以及每年的存活概率，活捉和放生的流浪信天翁的后续存活率约为更广泛人口预期存活率的 40%。