The aim of this study was to use scat analysis to analyse the dietary composition of the South American sea lion (SASL, Otaria byronia) over a short temporal scale and in different but closely located colonies in the Humboldt Current System of northern Chile. Scat samples were collected at Arica (18°34′S), Iquique (20°48′S) and Mejillones (23°04′S) during the summer (January to March) and winter (July) of 2015. A total of 16 595 individual prey items from nine species were found in 194 of the 215 scat samples. In general, squat lobster (Pleuroncodes monodon) was the most important prey item for the sea lion diet, both by number and according to the index of relative importance (%IRI), followed by anchovy (Engraulis ringens), which was the most frequent prey item in the scats and the most important by weight. Patagonian squid (Loligo gahi) ranked third in importance in the sea lion diet. However, some spatiotemporal variations in the consumption of prey were found. Squat lobster was the most important prey for sea lions in Arica and Iquique, while anchovy was the dominant prey in Mejillones. Regarding seasonal variation, squat lobster was more important in winter than in summer in the three localities, while anchovy was also more important during winter, except in Mejillones where the levels of consumption of this prey were similar in both seasons. These results show that SASL adjust their dietary preferences, modifying the contribution of different prey both spatially and temporally. Spatiotemporal variations in the SASL diet can be explained by temporal changes in the distribution and abundance of their prey.

中文翻译：

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东南太平洋上升流区机会捕食者的饮食组成

这项研究的目的是使用粪便分析法分析智利海马的短时间内在不同规模但位置较近的殖民地中南美海狮（SASL，Otaria byronia）的饮食组成。2015年夏季（1月至3月）和冬季（7月）分别在Arica（南纬18°34′），Iquique（南纬20°48′）和Mejillones（南纬23°04′）采集了粪便样本。在215个粪便样本中的194个中发现了来自9个物种的16595个个体猎物。一般而言，深蹲龙虾（Pleuroncodes monodon）是海狮饮食中最重要的猎物，无论是数量还是相对重要性指数（％IRI），其次是an鱼（Engraulis ringens）），这是粪便中最常见的猎物，也是最重的食物。巴塔哥尼亚鱿鱼（Loligo gahi）在海狮饮食中的重要性排名第三。但是，在猎物的消费中发现了一些时空变化。在阿里卡和伊基克，深海龙虾是海狮最重要的猎物，而was鱼是梅吉永斯的主要猎物。关于季节变化，在三个地区，冬季比夏季，深蹲龙虾更重要，而冬季，an鱼也更重要，除了在梅吉利翁斯，这两个季节的猎物消费水平相似。这些结果表明，SASL调整了他们的饮食偏好，在空间和时间上改变了不同猎物的贡献。SASL饮食中的时空变化可以通过其猎物的分布和丰富程度的时间变化来解释。