Baetscher Diana S, Beck Jessie, Anderson Eric C, Ruegg Kristen, Ramey Andrew M, Hatch Scott, Nevins Hannah, Fitzgerald Shannon M, Carlos Garza John
University of California Santa Cruz Santa Cruz California USA.
NOAA Southwest Fisheries Science Center Santa Cruz California USA.
Evol Appl. 2022 Mar 4;15(3):447-458. doi: 10.1111/eva.13357. eCollection 2022 Mar.
Global fisheries kill millions of seabirds annually through bycatch, but little is known about population-level impacts, particularly in species that form metapopulations. U.S. North Pacific groundfish fisheries catch thousands of Northern Fulmars () each year, making fulmars the most frequently caught seabird in federally managed U.S. fisheries. Here, we used genetic stock identification to assign 1,536 fulmars sampled as bycatch to one of four Alaska breeding colonies and quantified the similarity of bycatch locations at sea among colonies. We found disproportionately high bycatch from the Pribilof Islands (6% of metapopulation, 23% of bycatch), and disproportionately low bycatch from Chagulak Island (34% of metapopulation, 14% of bycatch). Overlap between fisheries and colony-specific foraging areas diverge more during the summer breeding season, leading to greater differences in bycatch susceptibility. Contemporary and historical gene flow likely contributes to low genetic differentiation among colonies (F = 0.003-0.01), yet these values may not represent present connectivity. Our findings illustrate how genetic stock identification can link at-sea threats to colonies and inform management to reduce bycatch from impacted colonies.
全球渔业每年因兼捕导致数百万海鸟死亡，但对于种群水平的影响却知之甚少，尤其是在形成复合种群的物种中。美国北太平洋底层鱼类渔业每年捕获数千只厚嘴海鸦，使厚嘴海鸦成为美国联邦管理渔业中最常被捕获的海鸟。在此，我们使用遗传种群鉴定方法，将作为兼捕样本采集的1536只厚嘴海鸦归为阿拉斯加四个繁殖地之一，并量化了各繁殖地在海上兼捕地点的相似性。我们发现，普里比洛夫群岛的兼捕比例过高（占复合种群的6%，兼捕量的23%），而查古拉岛的兼捕比例过低（占复合种群的34%，兼捕量的14%）。在夏季繁殖季节，渔业与特定繁殖地觅食区域之间的重叠差异更大，导致兼捕易感性的差异也更大。当代和历史基因流可能导致各繁殖地之间的遗传分化较低（F = 0.003 - 0.01），然而这些值可能并不代表当前的连通性。我们的研究结果表明，遗传种群鉴定可以将海上威胁与繁殖地联系起来，并为管理工作提供信息，以减少受影响繁殖地的兼捕量。
