Incidental mortality of marine birds in fisheries is an international conservation concern, including in Canada where globally significant populations of vulnerable diving species overlap with coastal gillnet fisheries. In British Columbia (BC), commercial salmon gillnet fishing effort was historically very high (>200,000 days fished annually in the early 1950's), and although this fishery has declined, over 6,400 days were fished annually in the 2006–2016 decade. Observations of seabird bycatch within the commercial fishery, however, are limited in both scope (comprising <2% of cumulative effort 2001–2016) and in time (being available only from 1995 onwards and only for a small number of areas). Using onboard fishery observer data from commercial, test and experimental fisheries (1995–2016), we developed two models to estimate the number of marine birds captured per set in sockeye (Oncorhynchus nerka) and chum (O. keta) salmon gillnet fisheries employing a Generalized Linear Mixed Modeling (GLMM) approach in a hierarchical Bayesian framework, with observer data post-stratified by fisheries management area and year. Using estimates of total commercial fishing effort (estimated number of sets, 2001–2016) we applied the models to extrapolate annual take for the main bird species (or groups) of interest. Multinomial probability estimates of species composition were calculated based upon a sample of 852 birds identified to species that were associated with sockeye or chum fisheries, enabling estimates (with CIs) of potential numbers of the mostly commonly observed species (common murres (Uria aalge), rhinoceros auklets (Cerorhinca monocerata), and marbled murrelets (Brachyramphus marmoratus)) entangled annually in commercial sockeye and chum salmon gillnet fisheries throughout BC. Conservative estimates of annual losses to entanglement were greatest for common murres (2,846, 95% CI: 2,628–3,047), followed by rhinoceros auklets (641, CI: 549–770) and marbled murrelets (228 CI: 156–346). Populations of all three of these alcids species are currently in decline in BC and entanglement mortality is a conservation concern. Gillnet mortality has been identified as a longstanding threat to marbled murrelet populations, which are recognized as Threatened in the Canada and the United States of America (USA). In addition, 622 (CI: 458–827) birds from 12 other species were estimated to be entangled annually. We conclude that cumulative mortality from incidental take in salmon gillnet fisheries is one of the largest sources of human-induced mortality for marine birds in BC waters, a conservation concern impacting both breeders and visiting migrants.

渔业中海鸟的偶然死亡是国际保护方面的关注，包括加拿大，在全球范围内，大量脆弱的潜水物种种群与沿海刺网渔业重叠。在不列颠哥伦比亚省（BC），商业鲑鱼刺网的捕捞努力历来非常高（1950年代初期每年捕捞> 200,000天），尽管这种捕捞量有所减少，但在2006–2016十年间，每年捕捞量超过6,400天。但是，在商业渔业中观察到的海鸟副渔获物在范围（占2001-2016年累计工作量的<2％）和时间（仅从1995年开始，仅在少数地区可用）方面都受到限制。使用商业，测试和实验性渔业的船上渔业观察员数据（1995-2016年），在分级贝叶斯框架中采用广义线性混合建模（GLMM）方法的Oncorhynchus nerka和Chum（O. keta）鲑鱼刺网渔业，并按渔业管理区域和年份对观察者数据进行后分层。我们使用商业捕鱼总努力的估算值（估计的套数，2001-2016年），将这些模型应用到所关注的主要鸟类（或群体）的年摄入量上。物种组成的多项概率估计值是基于对与红眼或密歇根渔业相关的物种鉴定出的852只鸟类的样本计算得出的，从而能够估计（最常见的）物种（最常见的海鼠（Uria aalge ），犀牛小菜（Cerorhinca monocerata）和大理石的murrelets（Brachyramphus marmoratus））每年在整个卑诗省的商业红鲑和密宗鲑鱼刺网渔业中纠缠在一起。保守估计每年的纠缠损失最大的是普通鼠（2,846，95％CI：2,628–3,047），其次是犀牛小a鱼（641，CI：549–770）和大理石鱼（228 CI：156–346）。目前，这三个类群的种群的不列颠哥伦比亚省都在下降，纠缠死亡率是一个保护问题。刺网死亡率已被确认是对大理石紫菜种群的长期威胁，被认为是受威胁的在加拿大和美利坚合众国（美国）。此外，据估计每年还纠缠了来自其他12个物种的622（CI：458–827）只鸟类。我们得出的结论是，鲑鱼刺网渔业偶然捕捞造成的累积死亡率是不列颠哥伦比亚省水域人为致死的最大人为原因之一，对保护的关注影响了繁殖者和来访的移民。