Noise pollution underwater a big concern in effort to save Puget Sound orcas

SEATTLE -- When it comes to saving our southern resident killer whales, there's three basic factors the Governor's Orca Task Force is looking at. Too few Chinook salmon, toxins in the water-- and ship noise affecting the whales.

Scientists are only beginning to learn about the sounds of the deep and how they affect our Puget Sound orcas. But, what they do know is it's a big concern.

While Puget Sound looks pretty peaceful, it's really a noisy place. And if you're more than three feet underwater-- it's a REALLY noisy place. And that sound travels faster, louder and farther in the water than in the air.

"Sound travels very efficiently in water," says Scott Veirs, the coordinator for the Orca Sound Hydrophone Network.

A hydrophone is an underwater microphone. And researchers started listening to Puget Sound for whale calls on dark and foggy days when they couldn't find them visually about a decade ago. They quickly discovered that wasn't the only show in town.

"We found that ships were dominating the soundscape," says Veirs. "And the noise from ships was present for most of the day."

That's a big problem for southern resident killer whales that hunt fish with sound.

"They send out a click through their forehead and expect it to bounce off a chinook maybe 10, maybe 50 feet away and then listen to the echo from that little fish," says Veirs.

And from 20 to 30 giant container ships that enter and exit Puget Sound daily, to the more regular ferries that go back and forth, many make noise that's louder and sometimes at the same pitch the whales use to hunt.

"If there were abundant salmon, which we wish there were in Washington state -- the noise might not be an issue," says Veirs. "But when salmon is scarce -- particularly the Chinook salmon the killer whales prefer -- noise is probably quite important."

While Canada has started providing incentives for ships to slow down heading through B.C. waters, slowing them down can make the noise pollution last longer. Veirs says while the U.S. Navy has pioneered quieter ship technology decades ago, much of the private shipping fleet has yet to bother to catch up.

He says there's much to learn about how whales respond to noise. But figuring it out could have huge paybacks in how to best help Puget Sound whales recover.

"The magic bullet could be noise," says Veirs. "There's a recent paper that suggests that if we decrease noise by 50%, we don't have to recover salmon nearly as much."

But funding dollars for research is in short supply -- and so is the timeline to save our orcas, which now only number 76 in Puget Sound.

You can connect your headphones to live hydrophones 24/7 at this link from Orca Sound.