Southern Resident killer whales (SRKWs) (Orcinus orca) are an endangered population in the United States and Canada, partly due to declines of their primary prey species, Chinook salmon. Prey availability influences various aspects of SRKW behavior, including distribution patterns and social structure. Yet, it is unclear to what extent a limited prey source influences the frequency of surface‐active behaviors (SABs), behaviors with important ecological implications. Here, we used long‐term datasets (1996–2019) to examine the relationships between the abundance of Chinook salmon, vessel presence, and the frequency with which SRKWs perform SABs. Salmon abundance was a significant predictor of SAB frequency, with fewer SABs performed in times of lower salmon abundance. SRKWs displayed more SABs when more whale watching vessels were present, and the whales spent a greater amount of time in the study area, performing more milling as opposed to traveling behavior, when vessel numbers were higher. Lastly, we found pod‐specific differences, such that K pod displayed significantly fewer SABs than either J or L pods. The observed relationships between SRKW behavior and both salmon abundance and vessel presence have implications for social network cohesion and foraging success. Our study adds to a growing body of literature highlighting factors affecting SRKW behavior as they experience increased threats from decreased prey availability, habitat loss, and anthropogenic disturbance, with implications for trans‐boundary management and conservation efforts.

中文翻译：

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濒危虎鲸（Orcinus orca）种群的表面行为与猎物的丰度和血管有关

南方居民虎鲸（Orcinus orca）是美国和加拿大的濒危种群，部分原因是其主要猎物奇努克鲑鱼的数量减少。猎物的可利用性会影响SRKW行为的各个方面，包括分布模式和社会结构。然而，尚不清楚有限的猎物来源在多大程度上影响表面活性行为（SAB）的频率，这些行为具有重要的生态意义。在这里，我们使用长期数据集（1996-2019年）来检查奇努克鲑鱼的丰度，船只的存在以及SRKW执行SAB的频率之间的关系。鲑鱼丰度是SAB频率的重要预测指标，在鲑鱼丰度较低时执行的SAB较少。当有更多的观鲸船时，SRKW显示更多的SAB，当船只数量更多时，鲸鱼在研究区域花费了更多的时间，进行了更多的碾磨而不是行驶行为。最后，我们发现了特定于Pod的差异，例如，K Pod显示的SAB明显少于J Pod或L Pod。观察到的SRKW行为与鲑鱼丰度和船只存在之间的关系对社交网络的凝聚力和觅食的成功具有影响。我们的研究增加了越来越多的文献，突出了影响SRKW行为的因素，因为它们受到猎物可利用性减少，栖息地丧失和人为干扰的威胁增加，对跨界管理和保护工作产生了影响。因此K荚显示的SAB明显少于J或L荚。观察到的SRKW行为与鲑鱼丰度和船只存在之间的关系对社交网络的凝聚力和觅食的成功具有影响。我们的研究增加了越来越多的文献，突出了影响SRKW行为的因素，因为它们受到猎物可用性降低，生境丧失和人为干扰的威胁增加，对跨界管理和保护工作产生了影响。因此K荚显示的SAB明显少于J或L荚。观察到的SRKW行为与鲑鱼丰度和船只存在之间的关系对社交网络的凝聚力和觅食的成功具有影响。我们的研究增加了越来越多的文献，突出了影响SRKW行为的因素，因为它们受到猎物可用性降低，生境丧失和人为干扰的威胁增加，对跨界管理和保护工作产生了影响。