SCOTT SIMON, HOST:
Things changed so much in 2020 as the effects of the coronavirus pandemic reached all parts of the world. And as we reported last July, that reach included underwater.
(SOUNDBITE OF WHALE SINGING)
SIMON: That's a humpback whale singing in Glacier Bay, Alaska. Scientists say the oceans have become quieter as shipping traffic has fallen. That could provide some relief for marine mammals, as NPR's Lauren Sommer reports.
(SOUNDBITE OF ARCHIVED NPR BROADCAST)
LAUREN SOMMER: A lot of scientists have had to cancel their field work this year, but not Christine Gabriele. She can work all alone in a boat on Glacier Bay. On a cool rainy morning, she spots what she's looking for and captures it on her smartphone.
CHRISTINE GABRIELE: Yeah, there are about five whales working this one little area, breathing when they're up.
(SOUNDBITE OF WHALE BREATHING)
SOMMER: They're humpback whales.
GABRIELE: It looks to me like they might be feeding on some schools of fish.
(SOUNDBITE OF WHALE BREATHING)
SOMMER: Gabriele is a wildlife biologist with Glacier Bay National Park. For 35 years, the park service has been keeping track of the humpback population here.
GABRIELE: One of the groups is a mother and calf, our seventh for the year. So that's really good news.
SOMMER: Gabriele also keeps track of them below the surface.
(SOUNDBITE OF WHALE SINGING)
SOMMER: Down at the bottom of the bay, there's a hydrophone continually recording. Sound can travel for miles underwater, a lot farther than a whale can see. And humpbacks make all sorts of calls. They coordinate feeding or just stay in touch. But there are other things in the water that make noise, too.
(SOUNDBITE OF WAVES LAPPING)
SOMMER: Pre-pandemic, boats and cruise ships were common in Glacier Bay, and Gabriele and her colleagues found that when ships are loud, the whales change their calls - Kind of the way we talk at a loud party.
GABRIELE: In order to communicate with each other, they might have to be close together, they might have to repeat themselves, or they might have to wait for a quieter moment.
SOMMER: But this year, things sound different.
(SOUNDBITE OF WHALE CALLS)
GABRIELE: It's much quieter. And just by listening to it, you can tell.
SOMMER: The cruise ships are gone. Boat tours are way down.
GABRIELE: The pandemic has kind of created this unexpected opportunity for science, kind of a once-in-a-lifetime chance to look at whale communication behavior in its natural, undisturbed form.
SOMMER: And scientists are finding that elsewhere in the Pacific, too.
(SOUNDBITE OF WHALE CALLS)
DAVID BARCLAY: So the southern resident killer whales are an endangered group of whales.
SOMMER: David Barclay is an assistant professor at Dalhousie University. He measured ocean noise in the waters near Vancouver, where those endangered killer whales live. He found there was about half as much noise in April compared to months prior.
BARCLAY: Even my mom said, it's kind of obvious, don't you think? Less ships, less noise - I mean, duh, which is - you know, it's always hard when you get roasted by your mom.
SOMMER: But it matters for killer whales because they need sound to hunt through echolocation, just like a bat does.
(SOUNDBITE OF WHALE CLICKING)
SOMMER: Ship sound can interfere with that, and it can cause chronic stress. But the quiet is likely a temporary thing says Michael Jasny, who works on marine mammals at the Natural Resources Defense Council.
MICHAEL JASNY: Right now there may be some break, but we have to look forward to what happens afterwards.
SOMMER: Jasny says the Port of Vancouver is a good example of where something is being done about ocean noise. Ships get a discount on their fees if they're retrofitted to be quieter or simply slow down, which reduces noise. But that's just in one place.
JASNY: You know, shipping is a global industry, and we're not seeing that kind of global commitment to change.
SOMMER: Still, Jasny's hope is that what scientists learn from whales now could help protect them from human noise in the future.
Lauren Sommer, NPR News.
SIMON: Lauren's report was first broadcast on Morning Edition in July.
(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.
