SEATTLE (AP) -- Harbor seals, sea lions and some fish-eating killer whales have rebounded in the Northeast Pacific Ocean in recent decades. But that boom comes with a trade-off: They're devouring more of the salmon prized by a unique but fragile population of endangered orcas.
A new study suggests that competition from other marine mammals - more so than from fishermen - may be a bigger problem for a small group of killer whales that spend time in inland waters of Washington state.
Researchers used models to estimate that from 1975 to 2015, marine mammals along the U.S. West Coast ate dramatically more chinook salmon, and that volume surpassed what was harvested by commercial and recreational fishermen from northern California to Alaska.
Scientists say the study quantifies yet another pressure on recovering imperiled salmon stocks.
The study published Monday in the journal Scientific Reports involved scientists with Oregon State University and NOAA Fisheries.