Endangered orcas compete with seals, sea lions for salmon
SEATTLE — Harbour seals, sea lions and some fish-eating killer whales have been rebounding along the Northeast Pacific Ocean in recent decades. But that boom has come with a trade-off: They’re devouring more of the salmon prized by a unique but fragile population of endangered orcas.
Competition with other marine mammals for the same food may be a bigger problem than fishing, at least in recent years, for southern resident killer whales that spend time in Washington state’s Puget Sound, a new study suggests.
Researchers used models to estimate that from 1975 to 2015, marine mammals along the U.S. West Coast ate dramatically more chinook salmon – from 6,100 metric tons to 15,200 metric tons, according to a study published Monday in the journal Scientific Reports.
In the same period, salmon caught by commercial and recreational fishing from Northern California to Alaska declined from 16,400 to 9,600 metric tons.