Northern orcas and Alaska residents may be eating up the best quality chinook salmon before they make it to the feeding grounds of the endangered southern resident killer whales (SRKW) in the Salish Sea. New research shows that each year these top ocean predators consume more than 2.5 million adult Chinook salmon along the West Coast. Except for the endangered southern resident killer whale (SRKW) population, all other fish-eating orca populations that live along the coast, called “residents,” are growing in number. There are approximately 300 northern resident killer whales and 2,300 Alaska residents, about three times as many as 30 years ago. The study also suggests that the declines in the body size of Chinook salmon over the past 50 years can be explained by intensified predation by growing populations of resident killer whales that selectively feed on large Chinook salmon, thus revealing a potential conflict between salmon fisheries and marine mammal conservation objectives.
