海角大神

We know this question has been keeping so many of you up at night: What does a cusk eel chorus sound like?

We often think of the ocean as a silent world, completely separate from our own. But it鈥檚 not so silent, and we鈥檙e not so separate. The ocean is quite noisy, and we鈥檙e making it even noisier, which has major ramifications that we鈥檙e just beginning to understand.

So yes, fish make sounds, and we have the audio to prove it.

Marine ecologist Leila Hatch and fellow fish listener Rodney Rountree 鈥� aka 鈥淐aptain Kirk of the fish world鈥� 鈥� serve as guides to the soundscape of the sea. Listen to the full audio story above.听

Note: This audio story was designed to be heard. We strongly encourage you to experience it with your ears, but we understand that is not an option for everybody. For those who are unable to listen, we have provided a听transcript of the story below.听(If you鈥檙e reading this off our website and don't see an audio player, click here to access the audio player.)

Transcript:

[Rhythmic cod grunting]听

EVA: That鈥檚 Dr. Leila Hatch. She studies the sounds of the ocean.

[Loud, fast haddock thumping]听

[Pensive music]

EVA: I鈥檓 Monitor science reporter Eva Botkin-Kowacki.听

We often think of the ocean as a whole other world, silent and completely separate from our own. But it鈥檚 not so silent. And we鈥檙e not so separate. The ocean is quite noisy, and we鈥檙e making it even noisier, which has major implications that we鈥檙e just beginning to understand.

[Upbeat music]

EVA: That鈥檚 Dr. Rodney Rountree. He calls himself 鈥淭he Fish Listener,鈥� because he鈥檚 on a decades-long quest to record and identify the many unknown sounds that fish make.

EVA: A hydrophone, by the way, is an underwater microphone.

My producer and I met Rodney on the town dock in Cotuit, Massachusetts on Cape Cod one July evening. We were hoping to experience the thrill of listening to a chorus of fish.听

Rodney showed up in a Hawaiian shirt that had a tropical fish design. He told us it was one of about 25 his mom had made for him before she died. He was all business at first. He dropped a hydrophone in the water, hooked it up to his laptop, a recorder, and two sets of headphones.

EVA: He also filled a small plastic kiddie pool with seawater, cast two fishing lines, and tossed traps into the water. Then the three of us settled into camping chairs, put on the headphones, and waited for something to happen.

[Time-passing music]

EVA: Sitting on the dock with Rodney, I was able to hear the underwater world unmuffled. It almost sounded like I had stepped onto another planet.

EVA: We were listening for one fish in particular: cusk eels. They get their name from their long, eel-like bodies. The males make a distinctive mating call right around sunset to attract females. And a bunch of them together makes quite the chorus underwater. Actually, 20 years ago, Rodney discovered that cusk eels live on Cape Cod by dropping a hydrophone in the water at the very same dock we sat on. But the night we met Rodney, the cusk eels were mysteriously quiet.听

EVA: As the hours ticked by, the sun set, the street lights nearby clicked on, and the stars started to come out. A steady dripping sound came from the hydrophone, which Rodney said probably meant his kiddie pool had a leak. But no cusk eels. I did hear another fish sound, though鈥�

EVA: Fish make sounds in a variety of ways. Sometimes they twitch muscles near their swim bladders or rub body parts together. But some scientists 鈥撎齊odney included 鈥撎齭ay that they also might fart intentionally to communicate. That鈥檚 a controversial idea. In fact, when Rodney first heard freshwater fish make a farting noise, other scientists didn鈥檛 believe him and he couldn鈥檛 get a paper published or funding to do more research. It took him 10 years to prove that freshwater fish do make farting sounds. He and a colleague finally published a paper last year.听

EVA: And sound also really matters to fish...听

EVA: Some fish use sounds for communication, navigating their environment, attracting a mate, or scaring off predators. So sound is pretty important in a fish鈥檚 life. And sound travels more than four times as fast underwater.

听

EVA: That means that sound travels really efficiently through water. So in deep ocean conditions, some noises can travel over hundreds of thousands of miles.听

EVA: Rodney鈥檚 talking about how all animals with a spine evolved from fish 鈥撎齢umans included. Whether intentionally or not, humans tend to see themselves as the center of the universe. But clearly for Rodney, fish are also pretty important. He talks about them like they鈥檙e people. Even when he catches them on a line or in a trap.

EVA: Catching fish is actually part of how he does his research. Dropping a hydrophone in the water is a passive approach. But when he catches a sea creature, he鈥檒l put it in his kiddie pool and gently nudge it to see if it will make a noise. He calls this technique, 鈥渁uditioning.鈥�

EVA: Scientists actually don鈥檛 know a lot about the ocean. It鈥檚 one of the least-explored parts of our world. And fish sounds? They鈥檝e only just begun to identify them.听

EVA: Whales and dolphins have captured people鈥檚 fascination. They鈥檙e often the stars of nature documentaries and crop up in pop culture, like in the movie 鈥淔inding Nemo.鈥澨�

[鈥淔inding Nemo鈥� clip. Dory imitates whale sounds: Wooooooooaaaaaaahhhh. Marlin: Dory. Dory this is not whale. You鈥檙e speaking like upset stomach. Dory: Maybe I should try humpback.]

EVA: People鈥檚 fascination with whales has led to more curiosity about ocean sounds听鈥撎齛nd that, in turn, led us to wonder: Do human sounds affect ocean animals?

[Wonder music]

Researchers have already found that human sounds can seriously affect fish. On the most extreme end, explosive sounds, like from oil and gas exploration, [boom!] can reverberate through the water and cause a fish鈥檚 swim bladder to burst, killing it. [boom!] Loud noises can also damage fish eardrums, just as listening to music too loudly can injure ours. And sometimes human noise just makes it too loud for creatures to use sound to communicate.

EVA: And for those chorusing male cusk eels, that might mean they can鈥檛 find a mate, which could have tragic consequences for the species. But could the fish just get louder?

EVA: When a boat went by the Cotuit town dock, the sound coming through the hydrophone was so loud compared to everything else underwater that I had to rip the headphones off to protect my ears.听

Here鈥檚 what the boat sounded like above water:

[Speed boat sounds above water, voices of some people on the boat chatting over a low hum]

EVA: And the same few seconds below the surface:

[Speed boat sounds below water, grating sound like ice in a blender]

EVA: Those little speed boats are just a small part of human noise in the ocean. Oil drilling, construction, military sonar, and ship engines create a ton of noise. And, by the way, over 90% of the world鈥檚 trade is moved by sea. That鈥檚 a lot of massive ships, and they鈥檙e a lot noisier than the small boats at the Cotuit town dock.听

EVA: There鈥檚 another reason to shop local.听

Ship engines can also be made quieter. In fact, as Leila told me, boat builders already mute the noise they make above water. But underwater, that鈥檚 not the case. So some scientists are advocating for regulations mandating quieter engines.

[Trickling water]

EVA: Back on the Cotuit dock, boaters had all gone home and it was quiet. Four hours had passed, and yet still we waited.

EVA: Rodney wasn鈥檛 quite sure what was happening with the cusk eels. He did say the chorus had been quieter in recent years. He didn鈥檛 think boats had scared them off. But it might have been another human influence. Fertilizer and septic tank run-off might make the water less habitable for cusk eels, and the population might be dwindling.听

EVA: In the end, we didn鈥檛 hear the cusk eel chorus that night. We did hear several other fish sounds, though. There was the fish fart. [Squeaky fart noise] A clucking sea robin. [Sea robin clucks] Several toadfish honks. [Medley of toadfish honks] Something that might have been a distant toadfish growl. [Toadfish growl] And a noise Rodney couldn鈥檛 identify that sounded a bit like Donald Duck. [Unknown fish sound].

But the cuskeels didn鈥檛 show.听

EVA: Rodney told me later that his hydrophone did pick up one cusk eel calling for a mate, but it happened during a brief moment when neither of us had our headphones on. He sent me the recording:

[Single cusk eel calling for a mate, sounds a bit like a woodpecker pecking]

EVA: Rodney also sent me a recording of the cusk eel chorus from a noisier night. And let me just warn you, it鈥檚 not exactly what you might expect of a 鈥渃horus.鈥� Still, there is something hauntingly beautiful about it.听

[Cusk eel chorus, sounds a bit like cicadas]

Credits:

EVA: Thanks for listening. This story was part five of 鈥淧eering into the deep,鈥� a five-part series exploring our evolving understanding of life beneath the waves. To check out the rest of the series, go to csmonitor.com/Peeringintothedeep.听

This audio story was reported by me, Eva Botkin-Kowacki. My producer was Rebecca Asoulin. Editing by Samantha Laine Perfas and Noelle Swan. Sound design and engineering by Noel Flatt and Jeff Turton. Special thanks to Em Okrepkie and Erin McNeill. Fish sounds are courtesy of Dr. Rodney Rountree and the National Oceanic and Atmospheric Administration.

This story was produced by 海角大神, copyright 2019.