Short Wave - Eavesdropping On Whales In A Quiet Ocean

Episode Date: July 27, 2020

The pandemic has led to a drop in ship traffic around the world, which means the oceans are quieter. It could be momentary relief for marine mammals that are highly sensitive to noise. NPR's Lauren Sommer introduces us to scientists who are listening in, hoping to learn how whale communication is changing when the drone of ships is turned down.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Maddie Safaya here with NPR climate correspondent Lauren Summer. Hey, Lauren. Hey, Maddie. So today you promised me a story about the coronavirus pandemic that is not incredibly depressing. Yes, I will not let you down. And here, I'll give you a hint about what it's about. Ooh, it's a whale.

And by my expert ears, Lauren, I will guess it's a big. whale. Oh, expert. Yeah. That was a humpback whale in Glacier Bay National Park, Alaska. This is the time of year where they've arrived, they've migrated all the way from Hawaii to eat, basically. Those cold waters in Alaska have a lot of food. Okay, ready? I'm going to give you another one. Ooh, I'm getting like more of a free willy vibe from that one. Yeah, cetacean bonus points. Those are killer whales. They were recorded in April, swimming by the hydrophone that the National Park Service has installed down at the bottom of Glacier Bay. Hydrophone being an underwater microphone. Yeah, you got it. But what's really important here is what you're not hearing in those recordings, which is this. Oh, yeah, boat noise, aka human noise.

Like there's less humans out here making human touristy noises. Right, exactly. I mean, the cruise ships and the boat tours that people take to go see the glaciers, They're not happening. So the whales are getting a break from that noise underwater. And sound is really key for whales. It's how they experience the world. So today on the show, how the global slowdown is creating quieter oceans

and how scientists are using this moment to listen to how whales are responding. Which maybe could help protect them from underwater noise pollution in the future. This is Shortwave, the Daily Science Podcast. podcast from NPR. So the whales in Glacier Bay are hanging out for the summer in this newfound quiet. How much quieter are we talking about, Lauren? That's something scientists are measuring right now. Like Christine Gabriel, she's a wildlife biologist at Glacier Bay National Park in Alaska.

And, you know, while a lot of scientists have had to cancel their field work due to the pandemic this year, she hasn't. She gets in a boat all alone and heads out on the water to find whales. She recorded some of this on her smartphone for me. Yeah, there are about five whales working this one little area, breathing when they're up. One of the groups is a mother and calf, our seventh for the year. Whale 1428 in her cute little calf, so that's really good news. So you've got this little humpback family, chow and down, and this year they're out there on their own because humans are largely out of the picture.

Yeah, and normally this time of year, there are a lot of cruise ships and boat tours, which is how visitors see the glaciers of Glacier Bay National Park. And underwater, it sounds like this. I hate that. Yeah, and sound is incredibly important underwater. I mean, if you think about it, vision is not super useful because you really can't see very far underwater. But sound travels for miles, sometimes hundreds of miles. So for whales, that's what they rely on. We know that whales use sound in almost every aspect of their daily life.

They need sound to be able to detect their predators as well as their prey. And they also use sound to carry out their very long, complex social lives. So what you hear in Glacier Bay is humpbacks making these feeding calls. And then they make these contact calls, which is basically just keeping in touch with each other. Oh, and you also hear this in Glacier Bay. Lauren, what is that? That sounded like a giant burp. It's actually a male harbor seal. They make kind of this growling sound. And then there's a couple like smacks in there. That's actually a humpback slapping its fin on top of the water, which is also maybe a form of communication. Wow. So there's a lot going down out there. Yeah. And then when you mix humans in, this is what it sounds like. So are humpbacks like phased by that at all? Yeah. Basically, Christine says they do what you.

you and I would do at a loud party maybe, if you could remember what a loud party is like. Do you mean leave early without telling anybody? Is that what you mean? No, but we can talk about that if you want. No, you mean they get louder, right? Is that what you're saying? Exactly. The humpbacks kind of work around the noise. They call louder. Sometimes they repeat themselves. They have to move closer together. Or often they just call less. And studies have also shown that for other whales, a lot of loud noise can lead to chronic stress. After 9-11, actually, when shipping traffic also dropped, researchers found that stress hormones in right whales went down.

Oh, wow. Okay. Interesting. I didn't know that. So have the noise levels in this quieter glacier bay been measured since the pandemic started? Yeah. So kind of based on an early analysis, the loudest sounds that the whales experienced in May this year are about half as loud as a May from two years ago. And Christine and our colleagues are just, they're really interested in seeing how the humpax communication might change because of that. 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. I mean, it's not the first time we've heard this, right? Even amidst all this extremely sad human tragedy, the pandemic is creating some conditions in the natural world that are pretty, unique, like scientifically speaking. Yeah, exactly. And, you know, scientists are doing the same thing elsewhere. Noise levels have dropped in the waters near Vancouver and Seattle, too,

which is an area where you see a lot of shipping traffic. And it's also home to endangered killer whales known as Southern resident killer whales. That's a whale, Laura? I love that so much. I love that too. I would not have identified it as whale. Keep going, keep going. Yeah, and sound is super important for them, too, because they actually use it to hunt through echo location. Right. Like so similar to how bats do it, where they make a noise, it hits an object, and then they listen for sound to kind of bounce back to them. Yeah. And Noah researchers have studied this actually by putting these suction cup tags, like a hydrophone with suction cups. Oh yeah. I've seen that. Yeah, those on the back of the killer whale and it can record sound for like eight hours before it pops off. And what these whales do is they dive hundreds of feet in the deep looking for Chinook salmon, which is their main source of food. And, you know, it's dark down there. And what you hear is, they start clicking. I like that a lot. And, you know, salmon are pretty good swimmer, so if they find one, they have to hone in on it,

and then their clicks get really fast, almost like a buzz right before they catch it. And then you can actually hear the crunch. Is that actually the sound of a salmon's bones being crushed in the jaws of a killer whale? Yes, exactly. Wow, Lauren. First of all, thank you for this so much. I just want to say that. I mean, in scientific terms, it is a positive foraging outcome. But for killer whales, too, Sound plays a huge role in their social lives. I talked to one scientist, Marla Holt, who is a research wildlife biologist at Noah Fisheries,

and she spends a lot of time listening to the calls that these whales make. They're very chatty. When they get in a mode, they can be chatty-cathies. When you're trying to analyze calls, and they're like overlapping and talking over each other, you're like, ah, God. But it's fun. There are actually three pods of killer whales around the Seattle area. They're called the J, K, and L pods.

And each pod has its own distinct dialect. I mean, can we nerd out on this for a quick second? Yes, of course. So the pods, they share similar kinds of calls, but they make them a little differently. Like Marla says take this S2 call as it's known. J-Pod likes to put this little extra loop in the beginning of that call. But the L-Pod, the L-Pod whales that make that same. S2 call. They don't have that little loop in the beginning. It's like, you know, if you think of the way

that you would say the word car and then say it with a Boston accent. Like car versus ca. Yeah. Exactly. I think that's right. So what's cool is that, you know, Marla can just listen to the sound of these killer whales and she knows exactly what group is making those calls. So cool. And since they use sound for so many parts of their life, you know, they're coordinating how they feed, they're hunting together. There's the social behavior. I mean, she's spend their time trying to tease out what they're really saying. And that's important because ship sound could be interfering with that. Their sensory world is so different from ours.

And maybe that makes it harder or more challenging to convey the problem to people because people aren't sticking their ears in the water and listening in the same way to all of the big ships going by or the ferries or the fishing vessels. Right. And a big point here is that this break that they're getting is temporary, right? So as soon as, you know, everything opens up again and shipping traffic goes back up, so does the noise. Yeah. But the port of Vancouver is actually one of the few examples out there where they're really trying to reduce noise. The ships there can get a discount on their birthing fees, which is, you know, what they pay to dock there, if they take measures to be quieter. So that could mean retrofitting their ships, like altering or replacing the propeller, which is the thing that makes a lot of noise.

or they can just slow down, which also reduces noise. I mean, it's a voluntary program, but they are seeing a lot of participation. But, you know, this is just one place in the country, though. Right. It's just one place. But I think a lot of scientists are really hoping to learn things during the pandemic, you know, about how whales are responding without all that noise. That could really maybe help them with policies that could reduce noise in the future. All right, Lauren. I appreciate you and this like beautiful auditory journey you've taken us on today.

I mean, my pleasure. Anytime. This episode was produced by Abby Wendell, edited by Viet Le, and fact-checked by Rebecca Ramirez, a tiny humpback whale in the K-Pod specifically. I'm Maddie Safaya. Thanks for listening to Shortwave for NPR.