UNUSUAL MORTALITY IN THE DEPLETED COOK INLET BELUGA (DELPHINAPTERUS LEUCAS) POPULATION

Abstract

In 2003, an unusually high number of beluga (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). The National Marine Fisheries Service