Data from: Modelling the functional link between movement, feeding activity and condition in a marine predator

The ability to quantify animals’ feeding activity and the resulting changes in their body condition as they move in the environment is fundamental to our understanding of a population’s ecology. We use satellite tracking data from northern elephant seals (Mirounga angustirostris), paired with simultaneous diving information, to develop a Bayesian state-space model that concurrently estimates an individual’s location, feeding activity, and changes in condition. The model identifies important foraging areas and times, the relative amount of feeding occurring therein and thus the different behavioral strategies in which the seals engage. The fitness implications of these strategies can be assessed by looking at the resulting variation in individuals’ condition, which in turn affects the condition and survival of their offspring. Therefore, our results shed light on the processes affecting an individual’s decision-making as it moves and feeds in the environment. In addition, we demonstrate how the model can be used to simulate realistic patterns of disturbance at different stages of the trip, and how the predicted accumulation of lipid reserves varies as a consequence. Particularly, disturbing an animal in periods of high feeding activity or shortly after leaving the colony was predicted to have the potential to lead to starvation. In contrast, an individual could compensate even for very severe disturbance if such disturbance occurred outside the main foraging grounds. Our modelling approach is applicable to marine mammal species that perform drift dives, and can be extended to other species where an individual’s buoyancy can be inferred from its diving behavior.量化动物在环境中移动时的摄食活动及其引发的身体状况变化，是解析种群生态学机制的核心前提。本研究利用北象海豹（Mirounga angustirostris）的卫星追踪数据，结合同步获取的潜水行为信息，构建了贝叶斯状态空间模型（Bayesian state-space model），可同时估算个体的位置、摄食活动与身体状况变化。该模型可识别关键觅食区域与时段，估算区域内的相对摄食量，进而揭示北象海豹所采取的各类行为策略。这些策略的进化适合度效应，可通过个体身体状况的变异进行评估，而个体身体状况又会进一步影响其后代的身体状况与存活率。因此，本研究结果阐明了动物在环境中移动与摄食时，影响其决策的相关过程机制。此外，本研究展示了该模型可用于模拟迁徙不同阶段下的逼真干扰模式，并预测由此引发的脂质储备积累变化规律。尤其值得注意的是，在动物高摄食活动时段或离开繁殖群后不久施加干扰，预测可能会导致其饥饿死亡。与之相反，若干扰发生在主要觅食区域之外，即便干扰程度极强，个体也能够进行补偿。本建模方法适用于进行漂流潜水的海洋哺乳动物类群，还可拓展至可通过潜水行为推断个体浮力的其他物种。