BELLINGHAM, Wash. (AP) — Southern Resident killer whales have not had enough food for several years, which could affect their already small numbers. That’s according to a study by the University of British Columbia. Researchers looked at the availability of prey for Northeastern Pacific Southern Resident killer whales. The study found a fluctuating level of salmon from spawning areas on rivers had a detrimental effect on killer whale health, threatening a small and fragile group of whales. About 75 of the Southern Resident killer whales span from the California coast to British Columbia’s Queen Charlotte Islands. But a decrease in salmon threatens that population.