Icy Strait, Alaska (Photograph by Dena Matkin, North Gulf Oceanic Society.)

Abstract. Populations of killer whales in southeastern Alaska overlap with populations inhabiting Prince William Sound, Alaska and British Columbia, Canada. We synthesize the results of a 20-year study in Glacier Bay and Icy Strait, Alaska. Individuals were photo-identified and predation events documented. Foraging strategies of killer whales were compared to those documented in similar studies in adjacent areas. One hundred twenty of the resident form of killer whales, 150 of the West Coast transients, 13 of the Gulf of Alaska transients and 14 of the offshore form were photo-identified in the study area. Residents preyed primarily on silver salmon and Pacific halibut. The prey of transients were harbor seals (40 percent), harbor porpoise (23 percent), Steller sea lions (16 percent), seabirds (14 percent), Dall’s porpoise (5 percent) and minke whale (2 percent). Humpback whales were observed closely approaching transient groups that were attacking other marine mammals. Non-predatory interactions also occurred between killer whales and Steller sea lions. Figure 1. Transient killer whale cow and calf photographed i