Guadalupe fur seals (GFS), Arctocephalus philippii townsendi, an U.S. Endangered Species Act threatened pinniped, have recently reappeared in their historic range along the western seaboard of the continental United States. Starting 2005 through 2016, 169 GFSs stranded in Washington and Oregon, involving two designated unusual mortality events. The circumstances surrounding GFS strandings, mortality, and their increased presence in Oregon and Washington were analyzed during this study. Detailed necropsies, histopathology (n = 93), and epidemiological analysis found three main causes of death (COD): emaciation (44%), trauma (29%), and infectious disease (19%) and the factors associated with overall strandings and emaciation. Trauma included many cases found associated with fisheries interactions and clustered near the mouth of the Columbia River, where high levels of commercial fishing occur. The most common pathogens found associated with disease were Toxoplasma gondii, Sarcocystis neurona, and gastrointestinal helminths. Seasonality and upwelling were associated with higher stranding numbers regardless of COD. Seasonal migration into the region, coinciding with postweaning, suggests young GFSs are in search of prey and habitat resources. Reemergence of GFSs is likely due to conservation efforts, which have been critical for species recovery in the region. Continued monitoring is needed as this vulnerable species continues to rebound.

中文翻译：

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瓜达卢佩海狗在美国西北太平洋地区的再度出现：2005-2016年间搁浅事件的流行病学

瓜达卢佩海狗（GFS），即濒临灭绝的美国濒临灭绝物种法案philipii townsendi，最近在美国大陆西部沿海地区重新出现在其历史范围内。从2005年到2016年，有169个GFS滞留在华盛顿和俄勒冈州，涉及两次指定的非正常死亡事件。在这项研究中，分析了GFS搁浅，死亡率及其在俄勒冈州和华盛顿州的存在增加的情况。详细的尸检，组织病理学（n= 93），流行病学分析发现了三种主要的死亡原因（COD）：消瘦（44％），外伤（29％）和传染病（19％）以及与整体搁浅和消瘦相关的因素。创伤包括许多发现的与渔业相互作用有关的病例，聚集在哥伦比亚河口附近，那里有大量的商业捕鱼活动。发现与疾病相关的最常见病原体是弓形虫，神经肉囊藻和胃肠蠕虫。季节性和上升流与更高的搁浅数量相关，而与COD无关。断奶后季节性迁徙到该地区，这表明年轻的GFS正在寻找猎物和栖息地资源。GFS的重新出现很可能是由于保护工作，这对于该地区的物种恢复至关重要。由于这种脆弱物种继续反弹，需要继续监测。