Critically endangered Puget Sound orcas face possible extinction within 100 years, according to a new study published in the journal Scientific Reports.
The year 2016 was the deadliest year for southern resident orcas who frequent northwest waters in nearly two decades: six southern residents died. As of last year, there were only 79 left. Their diet consists almost entirely of chinook salmon—a food source that has had its population cut in half since the 1980s.
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International scientists looked at 40 years of data and found that threats include excessive noise, pollution and dwindling food supply. They also identified what would need to change to sustain the orcas.
According to the study, chinook salmon would have to be up by a third just to restore the orca population.
The presence of motorized vehicles — like whale-watching boats — is impacting the orcas' ability to forage for chinook. The vessels force the whales to hunt longer and deeper.
This struggle for food is a large part of what’s forced them into a 25 percent chance of becoming extinct in the next century, according to the report.
Protection zones west of the San Juan Islands are also being discussed as a solution.