Abstract: This article summarizes our observations from land and vessels of transient (Bigg’s) ecotype killer whales (Orcinus orca) in the Kuril Islands during the period 2002 to 2015. We also conducted a review of published information on the occurrence of these killer whales in the Kuril Islands. During 12 years of vessel observations, no cases of killer whales hunting marine mammals were observed. During land-based observations, Bigg’s killer whales were observed from land near two Kuril Islands: Brat Chirpoev Island and Dolgaya Rock. In total, eight instances of Bigg’s killer whale attacks on pinnipeds were observed: seven were directed toward Steller sea lions (Eumetopias jubatus) and one toward northern fur seals (Callorhinus ursinus). The behavior of killer whales during hunting corresponded to published descriptions of the tactics used by killer whales in other regions. According to the photo-identification analysis in July 2009 and July 2011, the same group of four Bigg’s killer whales was observed near Brat Chirpoev Island. These individuals were not found in any of the published catalogues of killer whales inhabiting the North Pacific. According to both the information collected by us and that in published literature, the predominant ecotype of killer whales summering in the Kuril Islands is the fish-eating (resident) ecotype.
Key Words: killer whale, Orcinus orca, Steller sea lion, Eumetopias jubatus, northern fur seal, Callorhinus ursinus, ecotype, foraging specialization, photo-identification, Kuril Islands
Document: Article
DOI: https://doi.org/10.1578/AM.44.3.2018.267
Page Numbers: 267-278