Norwegian killer whales (Orcinus orca) are thought to be generalists that feed primarily on fish, but some individuals have been observed targeting pinnipeds. In the study reported here, field observations of foraging behaviours formed the basis of a priori classification as either seal-eaters or fish-eaters. Concurrent collection of photographic identification and biopsies for stable isotope analysis were used to validate prey choice classification. We found through satellite tracking that whales classified as seal-eaters took different paths south after leaving the northern fjords seemingly optimized for pinniped predation. Specifically, we found that seal-eaters took paths that tightly followed the coastline, remaining on average 6.9 ± 10.7 km (mean ± SD, n = 315) from the coast, whereas fish-eaters moved offshore along the continental shelf, travelling on average 45.1 ± 30.2 km (n = 1534) from the coast. We also found that, compared to fish-eaters, seal-eaters displayed more movements directed towards harbour seal haul-outs (p = 0.001). As expected, our data suggest that the fish-eaters feed primarily on fish, whilst seal-eaters appear to opportunistically use diverse foraging strategies optimized for either fish or seals based on availability and preference. Our findings demonstrate that tracking data can elucidate Norwegian killer whale movements associated with different prey types and selection.

挪威虎鲸（Orcinus orca）被认为是主要以鱼类为食的多面性动物，但也有人观察到一些个体以鳍足类动物为食。在此报告的研究中，对觅食行为的实地观察形成了先验分类为食海豹 或 食鱼动物的基础 。同时收集照片识别和活检进行稳定同位素分析，用于验证猎物选择分类。我们通过卫星跟踪发现，被归类为 海豹食者的鲸鱼 在离开似乎最适合鳍足类捕食的北部峡湾后，采取了不同的路径向南。具体来说，我们发现 食海豹的路径紧紧跟随海岸线， 与海岸  平均保持 6.9 ± 10.7 公里（平均值 ± 标准差，  n = 315），而食鱼者 沿着大陆架向近海移动，平均移动 距离海岸45.1 ± 30.2 公里（n = 1534）。我们还发现，与 食鱼者相比， 食海豹 表现出更多针对斑海豹的捕捞动作（p  = 0.001）。正如预期的那样，我们的数据表明， 食鱼者 主要以鱼类为食，而 食海豹 似乎会根据可用性和偏好，机会主义地使用针对鱼类或海豹优化的多种觅食策略。我们的研究结果表明，跟踪数据可以阐明与不同猎物类型和选择相关的挪威虎鲸运动。