killer whale

Top predators (animals at the top of the food chain) play an important role in structuring terrestrial and marine ecosystems. Killer whales (Orcinus orca) are a top predator in the North Pacific ecosystem. However, their ecological role, particularly with respect to their impact on marine mammal populations, is not fully understood.

Theoretical models suggest that killer whale predation could have a substantial effect on Steller sea lions and other marine mammal populations. However, too little is known about sources of mortality and the abundance and dietary preference of killer whales in the North Pacific to determine the extent to which these models are applicable in the field.

A long-term study in the Gulf of Alaska and Bering Sea has been identifying distinct populations of killer whales and their dietary preferences. Other studies have concluded that killer whales are the biggest source of mortality of juvenile sea lions.

Results from these Consortium supported studies are contained in the following publication subjects:

Sources of Sea Lion Mortality  |  Predation and the Decline of the Steller Sea Lion – hypotheses  |  Predation and the Decline of the Steller Sea Lion – theoretical models  |  Identification of Killer Whales in Alaska |  Diets and Behaviors of Killer Whales that eat Marine Mammals


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