Extinction risk to orcas accelerating as researchers raise alarm

SEATTLE — Orca scientist Rob Williams always thought that conservation was a knowledge problem, that once science showed why a species was declining, people would fix it.

But new research published Tuesday concludes otherwise. Even in the case of one of the world’s most charismatic species, the endangered southern resident killer whales that frequent Puget Sound are facing an accelerating risk of extinction, a new population analysis shows.

Despite all we know about them and why they are declining, this species is hurtling toward extinction in plain sight — a peril scientists that published the paper memorably call “Bright Extinction,” oblivion happening right before our eyes.

“There is no scenario in which the population is stable,” said Williams, co-founder and chief scientist at the research nonprofit Oceans Initiative, and lead author on the paper published in Nature Communications Earth & Environment. “We have a generation or two where the population is not fluctuating around zero, it is fluctuating around a decline, then it accelerates to a faster rate of decline to extinction. That is without all the threats that are worsening. That was a real eye-opener. This is what the status quo will do.”

In their model, the scientists found the southern residents declining in population until falling off a cliff in about 50 years — two killer whale generations — with only about 20 of their family members left within a century. Accounting for increasing threats would make the picture worse.

This, Williams has had to face, is not a problem of adequate information. Instead, it’s a matter of inadequate action. “I assumed if only we had the right data we would make the right decisions. But … not only do we know their biology and the threats they face,” he said of the southern residents, “we have known these things for a very long time.”

Climate change accentuates the extinction risk. Warming water in the ocean disrupts ocean food webs that feed Chinook salmon — the primary prey of these orcas. And warming rivers hurt salmon survival and reproduction. Other threats, including ocean shipping traffic and other noise that disrupts orca hunting, and habitat destruction also are intensifying. Alteration of the environment is making it, at this rate, a place in which these co-evolved animals can no longer live.