BELLINGHAM, Wash. (AP) — Southern Resident killer whales of the U.S. and Canadian West Coast have not had enough food for several years, which could affect their already small numbers, according to a study by the University of British Columbia.

Researchers looked at requirements and 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, the Bellingham Herald reported.

“It really appears like...