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Age Specific Survival Rates of Steller Sea Lions at Rookeries with Divergent Population Trends in the Russian Far East

机译：在俄罗斯远东地区随着种群趋势的变化Stoke海狮在种群中的特定年龄成活率

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After a dramatic population decline, Steller sea lions have begun to recover throughout most of their range. However, Steller sea lions in the Western Aleutians and Commander Islands are continuing to decline. Comparing survival rates between regions with different population trends may provide insights into the factors driving the dynamics, but published data on vital rates have been extremely scarce, especially in regions where the populations are still declining. Fortunately, an unprecedented dataset of marked Steller sea lions at rookeries in the Russian Far East is available, allowing us to determine age and sex specific survival in sea lions up to 22 years old. We focused on survival rates in three areas in the Russian range with differing population trends: the Commander Islands (Medny Island rookery), Eastern Kamchatka (Kozlov Cape rookery) and the Kuril Islands (four rookeries). Survival rates differed between these three regions, though not necessarily as predicted by population trends. Pup survival was higher where the populations were declining (Medny Island) or not recovering (Kozlov Cape) than in all Kuril Island rookeries. The lowest adult (> 3 years old) female survival was found on Medny Island and this may be responsible for the continued population decline there. However, the highest adult survival was found at Kozlov Cape, not in the Kuril Islands where the population is increasing, so we suggest that differences in birth rates might be an important driver of these divergent population trends. High pup survival on the Commander Islands and Kamchatka Coast may be a consequence of less frequent (e.g. biennial) reproduction there, which may permit females that skip birth years to invest more in their offspring, leading to higher pup survival, but this hypothesis awaits measurement of birth rates in these areas.
机译：在人口急剧下降之后，斯特勒海狮在其大部分范围内都开始恢复。但是，西阿留申群岛和指挥官群岛的斯特勒海狮正在继续减少。比较具有不同人口趋势的地区之间的存活率可能会提供有关驱动动态的因素的见解，但是关于生命率的公开数据非常稀缺，尤其是在人口仍在下降的地区。幸运的是，在俄罗斯远东地区的雀巢中，有史无前例的带有标记的斯特勒海狮的数据集可供使用，这使我们能够确定22岁以下海狮的年龄和性别特异性存活率。我们着眼于俄罗斯人口分布趋势不同的三个地区的生存率：指挥官群岛（梅德尼岛群），东部堪察加半岛（科兹洛夫角群）和千岛群岛（四个群）。这三个地区的生存率有所不同，尽管不一定是人口趋势所预测的。种群减少（梅迪岛）或未恢复种群（科兹洛夫角）的幼崽存活率高于所有千岛群岛。在梅德尼岛发现了成年女性（> 3岁）最低的年龄，这可能是该地区人口持续下降的原因。但是，在科兹洛夫角发现了最高的成年存活率，而不是在人口增长的千岛群岛，因此，我们认为出生率的差异可能是造成这些人口差异趋势的重要原因。指挥官群岛和堪察加海岸幼崽的高存活率可能是那里繁殖频率较低（例如，每两年一次）的结果，这可能使跳过生育年限的雌性对其后代进行更多的投资，从而提高幼崽的存活率，但是这一假设有待进一步研究。这些地区的出生率

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