Three distinct killer whale subspecies coexist in the northeastern Pacific Ocean: resident killer whales (Orcinus orca ater), Bigg’s killer whales (Orcinus orca rectipinnus), and offshore killer whales (Orcinus orca orca). These subspecies differ in diet, social structure, appearance, and behavior. Southern Resident killer whales (SRKW) are a distinct population segment of the resident killer whale subspecies; they inhabit the coastal waters of Washington, Oregon, California, and British Columbia, Canada. In 2005, SRKW were listed as endangered under the U.S. Endangered Species Act. At the time of listing, we did not know enough about them to designate Critical Habitat beyond the inland waters of the Salish Sea. To address this data gap, we conducted Pacific Orca Distribution Surveys from 2004 to 2021 to document SRKWs’ winter range, as well as to improve our understanding of their behavior and habitat use outside of the Salish Sea. This report summarizes the methods and results of these surveys and discusses how they were integral to the revision of Critical Habitat to include the coastal waters of Washington, Oregon, and California.
Emmons et al. (Fri,) studied this question.