The North Pacific marine heatwave of 2014–2016 (PMH), one of the most geographically-extensive and severe marine heatwaves on record, resulted in widespread and persistent perturbation of the Gulf of Alaska and California Current ecosystems. Negative effects of the PMH on marine mammals have been observed, but are not yet well understood. The endangered Steller sea lion Eumetopias jubatus is an important top predator in the Gulf of Alaska that is also particularly vulnerable to sudden or severe ecosystem shifts. We examined survival of 4,178 known-aged Steller sea lions marked from 2000 to 2016 from Kodiak Island through Southeast Alaska, using mark-recapture models and 12,811 resightings collected from 2001 to 2021. Survival of adult females aged 3–15 was reduced -0.05 to -0.23 during the PMH in the areas east, but not west, of Cook Inlet. Survival of Kodiak females was unaffected by the PMH, but survival of Sugarloaf females aged 5–8 was reduced -0.13 from summer 2015 to summer 2016. Lowest survival in Southeast Alaska occurred from summer 2016 to summer 2017, but was also reduced from summer 2014 to summer 2016. Reduced survival continued post-PMH in Kenai Peninsula/Prince William Sound, but not in Southeast Alaska. Survival of adult males was insensitive to the PMH, except in Southeast Alaska where male survival was reduced -0.25 from summer 2016 to summer 2017. Prolonged or intermittent high adult female mortality may reduce population growth and initiate regional declines. Survival response of Steller sea lions to the PMH varied regionally despite similar patterns of ocean warming throughout our study area, suggesting areas east versus west of Cook Inlet were affected differently by the PMH, perhaps due to habitat and oceanographic differences.

中文翻译：

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海洋热浪过后阿拉斯加湾虎头海狮的存活率下降

2014-2016 年的北太平洋海洋热浪 (PMH) 是有记录以来地理范围最广、最严重的海洋热浪之一，对阿拉斯加湾和加利福尼亚海流生态系统造成了广泛而持续的扰动。已经观察到 PMH 对海洋哺乳动物的负面影响，但尚未得到充分了解。濒临灭绝的斯特勒海狮土鳖虫是阿拉斯加湾重要的顶级捕食者，也特别容易受到突然或严重的生态系统变化的影响。我们使用标记再捕获模型和 2001 年至 2021 年收集的 12,811 次重新观察，检查了 2000 年至 2016 年从科迪亚克岛到阿拉斯加东南部标记的 4,178 只已知年龄的斯特勒海狮的存活率。3-15 岁成年雌性的存活率降低了 -0.05 至-0.23 在 PMH 期间在库克湾东部而非西部地区。Kodiak 雌性的存活率不受 PMH 的影响，但 5-8 岁的 Sugarloaf 雌性的存活率从 2015 年夏季到 2016 年夏季减少了 -0.13。阿拉斯加东南部的最低存活率发生在 2016 年夏季到 2017 年夏季，但也从 2014 年夏季开始减少到 2016 年夏季。基奈半岛/威廉王子湾的 PMH 后生存率继续下降，但阿拉斯加东南部没有。成年男性的存活率对 PMH 不敏感，除了阿拉斯加东南部，从 2016 年夏季到 2017 年夏季男性存活率降低了 -0.25。成年女性死亡率长期或间歇性高可能会减少人口增长并引发区域下降。尽管整个研究区域的海洋变暖模式相似，但斯特勒海狮对 PMH 的生存反应在区域上有所不同，这表明库克湾东部和西部地区受到 PMH 的影响不同，这可能是由于栖息地和海洋学的差异。