Predation. The number of killer whales visiting the upper inlet appears to be small. However, they may prey upon CI beluga whales. NMFS has received reports of killer whales in Turnagain and Knik Arms, between Fire Island and Tyonek, and near 1This estimate includes 44 beluga whale carcasses found along the shoreline which had been harvested for subsistence. the mouth of the Susitna River. Native hunters have recently reported killer whales along the tide rip that extends from Fire Island to Tyonek (Huntington, 1999) and in Kachemak Bay. No quantitative data exist on the level of removals from this population due to killer whale predation or its impact; however, killer whale pods prey selectively on salmon or marine mammals, including beluga whales, in Cook Inlet. During a killer whale stranding in Turnagain Arm in August 1993, one observer reported that a killer whale regurgitated pieces of beluga flesh. A potential dietary shift may account for some of the more recent sightings of killer whales in Cook Inlet. On the other hand, pods of killer whales also feed on salmon, a prey of beluga whales. Therefore, seeing killer whales near beluga whales in the inlet does not necessarily imply that they are searching for beluga whales. Assessing the impact of predation by killer whales on CI beluga whales is difficult. Anecdotal reports often highlight the more sensational, mortalities on beluga whales due to killer whales, thereby overemphasizing their impact. Further, these reports are from the early 1980s when beluga whales were more abundant. Consequently, they are of minimal value in evaluating current impacts to the population of beluga whales in Cook Inlet.
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