Research Document 2017/035
Habitats of Special Importance to Resident Killer Whales (Orcinus orca) off the West Coast of Canada
By Ford, J.K.B., Pilkington, J.F., Reira, A., Otsuki, M., Gisborne, B., Abernethy, R.M., Stredulinsky, E.H., Towers, J.R., and Ellis, G.M.
Two populations of fish-eating Killer Whales, Northern Resident and Southern Resident, inhabit waters off Canada’s west coast. The populations were listed under the Species at Risk Act (SARA) as Threatened and Endangered, respectively, in 2003. As required by the SARA, efforts have since been underway to identify critical habitat for these populations. Partial critical habitat was identified for each of the two populations in the 2011 Resident Killer Whale Recovery Strategy, which included a schedule of future studies to identify additional areas of critical habitat. In this report, we identify two new areas of special importance to Resident Killer Whales that potentially meet the criteria for designation as critical habitat under the SARA. One area includes waters on the continental shelf off southwestern Vancouver Island, including Swiftsure and La Perouse Banks. The other area includes waters of west Dixon Entrance, along the north coast of Graham Island from Langara Island to Rose Spit. Long-term vessel-based field studies and remote passive underwater acoustic monitoring show that both areas are important year-round habitat for Resident Killer Whales, especially for feeding on the whales’ primary prey, Chinook Salmon. The biophysical functions, features and attributes of these habitats of special importance are described, and examples of activities likely to result in the destruction of these components of critical habitat are summarized.
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