SEASONAL MOVEMENTS AND FORAGING BEHAVIOR OF NORTHERN RESIDENT KILLER WHALES (ORCINUS-ORCA) IN RELATION TO THE INSHORE DISTRIBUTION OF SALMON (ONCORHYNCHUS SPP) IN BRITISH-COLUMBIA

The hypothesis that northern resident killer whales (Orcinus orca) mov e in response to the seasonal availability of salmon (Oncorhynchus spp .) was tested using sightings and acoustic recordings of whales and da ta on the timing and abundance of salmon in Johnstone Strait, off Vanc ouver Island, between 1984 and 1988, and from King Island, on the cent ral British Columbia coast, for a 2-month period in 1989. Whales were most abundant in Johnstone Strait between July and October when salmon migrate through the strait. Individual whales seen in the strait duri ng summer were observed around King Island in spring 1989, coinciding with local sockeye and chinook salmon runs. In Johnstone Strait during summer 1988, whales foraged along the shore and in areas of strong cu rrent, where salmon occur in high densities. However, less than half o f the 16 pods in the northern resident community were present on more than 15% of summer days (1984-1988). The occurrence of 6 pods (A1, A4, A5, C1, D1, and H1) in Johnstone Strait during summer was positively and significantly associated with sockeye and pink salmon abundance, w hereas pod G1 was positively and significantly associated with chum sa lmon.,Although we demonstrate an association between certain pods and certain salmon species, we cannot determine whether this reflects the true preference of pods or represents differences in the whales' arriv al times in Johnstone Strait that are related to other factors. Our da ta suggest that within the northern resident community, pods may have seasonal ranges.