Sound travels very well through water—much better, in fact, than it does through air. So it shouldn’t be surprising that many ocean animals make noise. They use sound to communicate, to navigate, and even to hunt. As Brandon Southall, a biologist who studies marine mammals and ocean noise, says, “Their whole world is acoustic. Almost everything they do is with sound.”

To a fish, the sea probably sounds more like a noisy lunchroom than a quiet library. Snapping shrimp crackle like popping popcorn. Dolphins click and whistle, organizing hunts. Lovelorn whales sing so loudly they can be heard hundreds of miles away. Even fish are surprisingly noisy, filling the water with squeaks, grunts, rustles, and pops.

Noisy New Neighbors

Yes, the ocean can be a noisy place. But these days the fish aren’t the only ones sounding off. They have more and more competition from human machines.

Every day, thousands of huge container ships chug across the world’s oceans, carrying everything from grain to sneakers. On top of the engine noise, the ships’ propellers constantly churn up millions of tiny bubbles that pop loudly against the metal blades. All that noise can make it hard for ocean animals trying to listen for friends or dinner.

Whales and dolphins bounce sound waves off objects to locate them in the water. This handy trick is called sonar. They catch the echoes with special sound sensors in their foreheads. From the shape of the echo, they can tell the size, distance, speed, and even fatness of potential prey. But this keen hearing also means that loud noises really hurt.

Ships and submarines also use sonar. But unlike dolphin sonar, human sonar is very loud! That’s because a ship’s “ears” aren’t as sensitive as a dolphin’s. Animals swimming nearby can be deafened, knocked unconscious, or even killed by a loud submarine sonar burst.

Underwater construction can also be dangerously loud. Big pounders called pile drivers are used to attach structures to the seabed. Each blow sends a powerful boom through the water. When new pilings were driven during repairs to the San Francisco–Oakland Bay Bridge, dead fish appeared by the site. When scientists examined the fish, they found that the force of the sound waves had popped the fishes’ swim bladders, an internal air sac that fish use to float—and to hear.

Geologists pound on the seafloor too, listening to the echoes to detect oil wells and map Earth’s layers. The results are useful to science, but all that hammering probably gives ocean animals a headache.

Turning Down the Volume

As people realize how important sound is to ocean animals, they are looking for ways to reduce human noise. Ships could get quieter just by slowing down—slower propellers make less noise. Engineers are also trying to find quieter propeller shapes.

To reduce construction noise, some companies are using a simple invention called a bubble curtain. A hose with lots of small holes sends up a wall of bubbles around the noisy machine. Sound waves passing through the bubbles lose energy and get quieter, making them less dangerous to animals. It seems to work—when bubble curtains were installed on the San Francisco bridge project, fish deaths dropped.

Fixing sonar noise is trickier since the sound pulses have to be loud to be useful. But the navy now posts lookouts and avoids loud sonar when whales and dolphins are near. We still have a lot to learn about sound in the oceans, but together we can help keep the sea a quieter place.

Shhhhhh! Fish talking.




واژه / عبارتفونتیک آمریکایی (GA)معنی انگلیسی سادهمعنی فارسی
acoustic/əˈkuː.stɪk/related to sound or hearingصوتی، وابسته به صدا و شنوایی
navigate/ˈnæv.ə.ɡeɪt/to find the right direction or pathمسیریابی کردن، جهت‌یابی کردن
snapping shrimp/ˈsnæp.ɪŋ ʃrɪmp/a type of shrimp that makes loud popping soundsمیگوی هفت‌تیرکش (میگوی صدادار)
crackle/ˈkræk.əl/to make short, sharp popping soundsترق‌توروق کردن، صدای ریز و خشک دادن
lovelorn/ˈlʌv.lɔːrn/sad because of loveعاشق دل‌شکسته، ناکام در عشق
grunt/ɡrʌnt/a short, low, rough soundصدای ناله یا خرناس کوتاه و بم
rustle/ˈrʌs.əl/a soft, dry sound like moving paper or dry leavesخش‌خش کردن
competition/ˌkɑːm.pəˈtɪʃ.ən/a situation where others try to get the same thingرقابت
propeller/prəˈpel.ɚ/curved blades that turn fast to push a ship or planeپروانه کشتی یا هواپیما
churn up/tʃɝːn ʌp/to mix or stir water or dirt violentlyشدیداً به هم زدن، متلاطم کردن
sonar/ˈsoʊ.nɑːr/a system that uses sound waves to find objects underwaterردیاب صوتی (سونار)
echo/ˈek.oʊ/a sound that bounces back off a surfaceپژواک، بازتاب صدا
prey/preɪ/an animal that is hunted and eaten by anotherشکار، طعمه
knock unconscious/nɑːk ʌnˈkɑːn.ʃəs/to make someone or something lose awareness or faintبی‌هوش کردن
burst/bɝːst/a sudden, short explosion or release of energy/soundفوران ناگهانی، انفجار یا شلیک لحظه‌ای
pile driver/ˈpaɪl ˌdraɪ.vɚ/a heavy machine used to pound posts deep into the groundشمع‌کوب (دستگاه کوبیدن پایه‌ها به کف زمین یا دریا)
swim bladder/ˈswɪm ˌblæd.ɚ/an air sac that helps a fish float and hearکیسه شنا (کیسه هوای درون بدن ماهی)
geologist/dʒiˈɑː.lə.dʒɪst/a scientist who studies rocks and the structure of Earthزمین‌شناس
bubble curtain/ˈbʌb.əl ˌkɝː.tən/a wall of rising bubbles used to block sound wavesپرده حباب
trickier/ˈtrɪk.i.ɚ/more difficult to deal withدشوارتر، قلق‌دارتر