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Two distinct populations of Resident Killer Whales (Orcinus orca), known as the Northern and Southern Residents, occupy the waters off the west coast of Canada. In 2001, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designated Southern Resident Killer Whales as Endangered and Northern Resident Killer Whales as Threatened. Both populations are listed in Schedule 1 of the Species at Risk Act (SARA). These two populations are acoustically, genetically, and culturally distinct. The “Recovery Strategy for the Northern and Southern Resident Killer Whales (Orcinus orca) in Canada” was finalized and published on the Species at Risk Public Registry in 2008. Minor amendments to the recovery strategy were made in 2011 to provide additional clarification regarding critical habitat for Northern and Southern Resident Killer Whales. This recovery strategy is herewith amended once again to include identification of additional critical habitat for these populations and to provide minor updates to background and species information. Additionally, sections of the recovery strategy have been reordered to align with current templates. This recovery strategy is considered one in a series of documents for this species that are linked and should be taken into consideration together; including the COSEWIC status report (COSEWIC 2008) and the Action Plan for the Northern and Southern Resident Killer Whale (Orcinus orca) in Canada (DFO 2017a). Recovery has been determined to be biologically and technically feasible. Resident Killer Whale populations in Canadian Pacific waters are presently considered to be at risk because of their small population size, low reproductive rate, and the existence of a variety of anthropogenic threats that have the potential to prevent recovery or to cause further declines. Principal among these anthropogenic threats are environmental contamination, reductions in the availability or quality of prey, and both physical and acoustic disturbance. Even under the most optimistic scenario (human activities do not increase mortality or decrease reproduction), the species’ low intrinsic growth rate means that the time frame for recovery will be more than one generation (25 years). The Southern Resident Killer Whale population has fluctuated between 70 and 99 individuals since 1976, and consisted of 74 members in 2018 (Center for Whale Research unpublished data). During the summer and fall, Southern Residents are primarily found in the trans-boundary waters of Haro Strait, Boundary Pass, the eastern portion of Juan de Fuca Strait, and southern portions of the Strait of Georgia. Some members of the population typically remain in the same general area in winter and spring, but others range over much greater distances, and have been reported as far south as central California, and as far north as southeastern Alaska. During the summer and fall, the principal prey of Southern Residents is Chinook and Chum Salmon (Oncorhynchus tshawytscha and O. keta); less is known of their diet in the winter and spring. The Northern Resident Killer Whale population experienced a decline of 7% between 1997 and 2002, but since that time has been increasing at a mean rate of 2.9% per year, reaching approximately 309 individuals in 2017 (Towers et al. 2015; Fisheries and Oceans Canada Cetacean Research Program (DFO-CRP) unpublished data). The population appears to spend the majority of its time from Campbell River and Alberni Inlet northwest to Dixon Entrance, but has been sighted as far south as Grays Harbor, Washington, and as far north as Glacier Bay, Alaska (Ford et al. 2000; 2017). Northern Residents also feed primarily on Chinook and Chum Salmon during the summer and fall. However, like Southern Residents, less is known of their winter distribution and diet, and this knowledge gap must be addressed to fully understand the principal threats affecting the population. The goal of the Resident Killer Whale recovery strategy is to: “ensure the long-term viability of Resident Killer Whale populations by achieving and maintaining demographic conditions that preserve their reproductive potential, genetic variation, and cultural continuity1 ”. In order to achieve this goal, four principal objectives have been identified. They are: Objective 1: ensure that Resident Killer Whales have an adequate and accessible food supply to allow recovery Objective 2: ensure that chemical and biological pollutants do not prevent the recovery of Resident Killer Whale populations Objective 3: ensure that disturbance from human activities does not prevent the recovery of Resident Killer Whales Objective 4: protect critical habitat for Resident Killer Whales and identify additional areas for critical habitat designation and protection A description of the broad strategies to be taken to address threats to the species’ survival and recovery, as well as research and management approaches needed to meet the recovery goal and objectives are included in section 6. These strategies helped to inform the development of specific recovery measures in the action plan for Northern and Southern Resident Killer Whales. However, significant gaps in knowledge about Killer Whales remain and numerous actions have been identified to address these knowledge gaps and to identify further directions for recovery. For Northern and Southern Resident Killer Whales, critical habitat is identified to the extent possible using the best available information, and provides the functions, features, and attributes necessary to support the species’ life-cycle processes and contribute to achieving the species’ recovery goal and objectives. This recovery strategy identifies critical habitat for Resident Killer Whales as four geographical areas: 1) the waters of Johnstone Strait and southeastern Queen Charlotte Strait (Northern Resident Killer Whale critical habitat); 2) transboundary waters in southern British Columbia, including southern Georgia Strait, Haro Strait, and Juan de Fuca Strait (Southern Resident Killer Whale critical habitat); 3) waters on the continental shelf off southwestern Vancouver Island, including Swiftsure and La Pérouse Banks (Northern and Southern Resident Killer Whale critical habitat); and 4) waters of west Dixon Entrance, along the north coast of Graham Island from Langara to Rose Spit (Northern Resident Killer Whale critical habitat) (section 7). The Action Plan for the Northern and Southern Resident Killer Whale (Orcinus orca) in Canada was finalized and posted on the Species at Risk Public Registry in 2017. Additionally, multispecies action plans developed by the Parks Canada Agency include recovery measures for Northern and Southern Resident Killer Whales.