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Unusual Mortality in the 2003 Depleted Cook Inlet Beluga Population

October 01, 2005

Scientists conducted an investigation into this sudden decline of the Alaska beluga whale population.

In 2003, an unusually high number of beluga whale (Delphinapterus leucas) deaths occurred in Cook Inlet, Alaska. This small population of whales is segregated geographically and genetically from all other populations of belugas in Alaska waters (O’Corry-Crowe and others 1997). Cook Inlet belugas display strong site fidelity and many remain year-round in the Inlet (Rugh and others 2004), making this population vulnerable to impacts from anthropogenic and environmental hazards (Calkins 1983; Moore and DeMaster 2000; Moore and others 2000). Factors that may presently impact the Cook Inlet beluga population include harvest by Alaska Natives, contaminants, boat traffic, killer whale (Orcinus orca) predation, strandings, disease, forage base decline, human-induced habitat changes, and an ocean regime shift (Vos 2003).


Daniel J. Vos and Kim E. W. Shelden. Published in Northwestern Naturalist 86:59–65 (Autumn 2005).

Last updated by Alaska Regional Office on 03/05/2019

Cook Inlet Beluga Whale Cook Inlet Beluga Whale Research Alaska Marine Mammal Stranding