Foraging strategies are of great ecological interest, as they have a strong impact on the fitness of an individual and can affect its ability to cope with a changing environment. Recent studies on foraging strategies show a higher complexity than previously thought due to intraspecific variability. To reliably identify foraging strategies and describe the different foraging niches they allow individual animals to realize, high-resolution multivariate approaches which consider individual variation are required. Here we dive into the foraging strategies of Galápagos sea lions (Zalophus wollebaeki), a tropical predator confronted with substantial annual variation in sea surface temperature. This affects prey abundance, and El Niño events, expected to become more frequent and severe with climate change, are known to have dramatic effects on sea lions. This study used high-resolution measures of depth, GPS position and acceleration collected from 39 lactating sea lion females to analyze their foraging strategies at an unprecedented level of detail using a novel combination of automated broken stick algorithm, hierarchical cluster analysis and individually fitted multivariate hidden Markov models. We found three distinct foraging strategies (pelagic, benthic, and night divers), which differed in their horizontal, vertical and temporal distribution, most likely corresponding to different prey species, and allowed us to formulate hypotheses with regard to adaptive values under different environmental scenarios. We demonstrate the advantages of our multivariate approach and inclusion of individual variation to reliably gain a deeper understanding of the adaptive value and ecological relevance of foraging strategies of marine predators in dynamic environments.

觅食策略具有极大的生态意义，因为它们对个体的健康有很大影响，并可能影响其应对不断变化的环境的能力。最近对觅食策略的研究表明，由于种内变异性，其复杂性比以前认为的要高。为了可靠地识别觅食策略并描述它们允许个体动物实现的不同觅食生态位，需要考虑个体差异的高分辨率多变量方法。在这里，我们深入了解加拉帕戈斯海狮 ( Zalophus wollebaeki ) 的觅食策略)，一种热带捕食者，面临着海面温度的巨大年度变化。这会影响猎物的丰度，而预计随着气候变化而变得更加频繁和严重的厄尔尼诺事件会对海狮产生巨大影响。本研究使用从 39 只哺乳期海狮雌性采集的深度、GPS 位置和加速度的高分辨率测量值，使用自动断棒算法、层次聚类分析和单独拟合的多元隐藏算法的新颖组合，以前所未有的详细程度分析它们的觅食策略马尔可夫模型。我们发现了三种不同的觅食策略（远洋、底栖和夜间潜水），它们的水平、垂直和时间分布不同，很可能对应于不同的猎物物种，并允许我们就不同环境情景下的适应性值制定假设。我们展示了我们的多元方法和包含个体变异的优势，以可靠地深入了解动态环境中海洋捕食者觅食策略的适应性价值和生态相关性。