Linda Crampton is a writer and teacher with an honors degree in biology. She loves to study nature and write about living things.

Sounds in the Ocean

The world below the ocean surface is often a noisy place, researchers say. At least one thousand types of fish—and probably many more—produce sounds. These vocalizations can take a wide variety of forms, including pops, clicks, whistles, purrs, grunts, groans, growls, barks, hums, hoots, rattles, and even tinkles.

Fish produce sounds to attract mates, warn of danger, scare competitors and predators, and maintain social cohesion. Some also create sound as a distress call. Although people have known for a long time that certain fish can vocalize, scientists have only recently realized how widespread and intriguing this ability is.

A gas-filled sac in the abdomen called a swim bladder is often responsible for fish sounds.

Discovering the Sounds

Researchers record fish vocalizations with the aid of an underwater microphone called a hydrophone. This may be lowered into the water from a boat or carried by a scuba diver. Until recently, divers were unaware of the wide variety of fish vocalizations in the ocean because the sound of bubbles being released from scuba equipment masked the sounds produced by the fish. In addition, the bubbles often disturbed fish and caused them to swim away.

Fish sound researchers are now using rebreathers instead of conventional scuba gear. A rebreather is a self-contained system in which the diver repeatedly breathes in his or her exhaled air, so no gas bubbles enter the water. Carbon dioxide is removed from the exhaled air inside the rebreather. An oxygen sensor monitors the level of oxygen in the rebreathed air, and a microprocessor controls the delivery of fresh oxygen into the air when it’s needed.

Internal Anatomy of a Fish

The Swim Bladder: The Source of Many Fish Vocalizations

Inside the abdominal cavity of most types of fish is a gas-filled sac called a swim bladder (the blue organ in the diagram above). A fish uses the sac to control its buoyancy. When gas is added to the swim bladder, the fish is more buoyant and can swim higher in the water. When gas is removed, the fish sinks in the water.

The swim bladder is filled in one of two ways. Some fish gulp air from the water surface. The air then passes through a duct connecting the esophagus to the swim bladder. The esophagus is the passageway that connects the mouth to the stomach. Other fish have a gas gland. This extracts gas from the blood and sends it into the swim bladder.

The oyster toadfish produces sound by the action of its sonic muscle on its swim bladder. NASA, via Wikimedia Commons, public domain image

How Do Fish Produce Sounds?

In some fish, the swim bladder is used as a sound-producing organ. A muscle attached to the swim bladder (the sonic muscle) contracts and relaxes in a rapid sequence. This action causes the swim bladder to vibrate and produce a low-pitched drumming sound. The sonic muscle of the oyster toadfish is able to contract at a rate of 200 times a second.

Another way in which fish may produce sounds is by stridulation, a process in which hard body parts like teeth or bones hit each other. Body movements that create water currents or splashes are also used to create sounds for communication.

The Bocon toadfish is in the same family as the three-spined toadfish. Toadfish are known for their ability to produce sounds. Wilfredor, via Wikimedia Commons, CC0 1.0 License

Toadfish Vocalizations

The Three-Spined Toadfish

Toadfish have a wide face that is reminiscent of a toad's. Their eyes are located towards the top of the head instead of on the side as in most fish. They usually live on the ocean bottom, where they are ambush predators. They are generally colored and patterned to help them blend in with their background. Male toadfish are known for their habit of producing sounds to attract females.

The three-spined toadfish, or Batrachomoeus trispinosus, lives in the western region of the Pacific Ocean. It's the only fish so far known to produce non-linear sounds. Normal sound is said to be linear. Non-linear sounds are loud and are beyond the usual range of the instrument or device that is producing them. The sound waves have a large amplitude and cause unusual effects in the materials that they travel through.

Non-linear sounds can produce intense sensations in humans and (apparently) in animals, too. Crying babies and animals such as marmots and songbirds emit non-linear sounds as alarm calls and to communicate distress. Film makers use music with non-linear sounds in movies to evoke emotions like fear and tension in viewers.

Three-spined toadfish have a swim bladder that is divided into two sections, forming two functionally separate areas. Each half of the swim bladder is controlled by its own sonic muscle and can produce its own sound. When each section of the swim bladder emits a different sound at the same time, the sound is said to be biphonic. Scientists are trying to discover what role the non-linear sounds play in the three-spined toadfish community.

Midshipman Vocalizations

Facts About the Plainfin Midshipman Fish

The plainfin midshipman is another type of toadfish and has the scientific name Porichthys notatus. The fish is notable for the light-emitting organs (photophores) on its surface, the sounds that it produces, and the fact that it can survive in the intertidal zone. The arrangement of the photophores reminds some people of the buttons on a naval uniform, which gave rise to the name "midshipman" fish.

Plainfin midshipman fish are found off the west coast of North America from Alaska to Baja California. In California, they are sometimes called “California singing fish”. During the mating season, the male hums—sometimes for long periods—by hitting his swim bladder with his sonic muscle. His humming is designed to attract a female. Once a female has been attracted and has deposited her eggs, the male resumes humming to lure another female to the nest. He guards the eggs until they hatch.

Researchers have discovered that there are two types of midshipman males—Type 1 and Type 2. Type 2 males are sometimes called “sneaker males”. They are smaller than Type 1 males and do not hum, although they can make other vocalizations. Instead, they try to sneak into the nest and quickly fertilize the eggs before the Type I males notice what they are doing.

The Plainfin Midshipman in Elkhorn Slough

Black Drum Facts and Sounds

The black drum (Pogonias cromis) is a black or grey fish that lives in the brackish water found in areas such as estuaries. Black drums are mainly bottom feeders. The young fish have black stripes on a light background, but the stripes fade as the fish matures. Adults can become very big and may weigh over a hundred pounds.

Black drums become very noisy during the mating season. The low-pitched sounds that they produce travel long distances. The males produce the sounds to attract females. The fish use their swim bladder and sonic muscle to create the vocalizations.

In 2005, residents in Cape Coral on the Florida Gulf Coast complained that they were being kept awake at night by low-pitched throbbing sounds in their homes, which they believed were being created by an engineering fault in the buildings. It was eventually discovered that the sounds were being created by black drum fish, which at first the residents found hard to believe. The fish had swum into the canals and estuaries in the area. Their mating calls were penetrating the ground and the seawalls and entering nearby houses.

Herring FRTs

Herring communicate with each other by forcibly expelling gas from the anal area, producing bubbles and a high-pitched sound. The researchers call this sound production an FRT (Fast Repetitive Tick). They did have another word in mind when they created the term, however.

Both the Atlantic herring (Clupea harengus) and the Pacific herring (Clupea pallasii) produce FRTs. The fish gulp air from the water surface and then store it in the swim bladder. During the night and when surrounded by other herring, air is released from the anal duct and out of the body through the anus. The gas that is emitted isn't made from the digestion of food, since captive herring produce the sounds whether or not they have been fed.

Herring have a good sense of hearing. The purpose of the FRT sounds may be to ensure that the fish stay close together in their schools, or large groups.

Herring Sounds

The DOSITS website (Discovery of Sound in the Sea) has an audio gallery of fish sounds and is enjoyable to explore. The web address of this gallery is given in the last reference below.

Catfish Vocalizations

Other Fish Sounds

Both ocean and freshwater fish produce sounds. Seahorses produce clicking sounds by rubbing two parts of their skull together. The weakfish—a type of drum—produces a purr with its sonic muscle and swim bladder. Squeaker catfish rub the spines located in their pectoral fins into grooves on their shoulders. Talking catfish can produce sound in two ways—by vibrating their swim bladder or by vibrating their pectoral fin spines in their sockets.

Research of sound production in fish is still in its infancy. As scientists continue their investigations, they are likely to find even more fish species that make sound and even more methods of fish vocalizations.

References

"Grunts of the Two-Bladdered, Three-Spined Toadfish Are More Like Birdsong Than You'd Think" from Discover Magazine

"Simple Toadfish Grunts May Contain Complex Information" from Wired

"What Singing Fish Reveal about Speech and Hearing" from Scientific American

Black Drum facts from Texas Parks and Wildlife

Information about Pacific and Atlantic herring produce FRTs from The Royal Society and Simon Fraser University

The discovery of sound in the sea database from the University of Rhode Island and the Inner Space Center

Questions & Answers

Question: What is the sound that a fish makes called?

Answer: Some animals have a special name for their sounds. A sheep bleats, for example, a duck quacks, a crow caws, and a dog barks. Fish are simply said to make or produce sounds, unless a specific fish is being discussed. Other words such as grunt or hum may then be used to describe the sound.

Question: What type of sound does a catfish make? Would it be considered a croak or maybe a grunt?

Answer: You could visit the Discovery of Sounds in the Sea website and listen to a catfish sound in order to classify it for your sense of hearing. I've found a recording of the sound produced by one species of catfish there. The sounds of catfish are quite variable depending on how they're made and the environmental conditions. The channel catfish (Ictalurus punctatus) is the most common species in North America. It produces sound by stridulation. It strikes part of its pectoral spine against its pectoral girdle.

© 2011 Linda Crampton

Linda Crampton (author) from British Columbia, Canada on February 03, 2020:

I appreciate all your visits and comments very much, Suchismita.

Suchismita Pradhan from India on February 03, 2020:

Wow what a well researched article.I have heard about dolphins making sounds but never heard abouts other underwater species.Lovely article.

Linda Crampton (author) from British Columbia, Canada on September 19, 2019:

I agree. It's interesting to learn about animal sounds.

physics on September 19, 2019:

it is good to learn the sounds of animals makes

Linda Crampton (author) from British Columbia, Canada on September 09, 2019:

Thanks for the comment, Fred. It sounds like you live in a very interesting area. Listening to the undersea world must be fascinating.

The "monstrous and demonic" sound that you hear is intriguing. If the University of Rhode Island can't identify the sound, it's highly unlikely that I would be able to. I hope you eventually identify its source.

Fred on September 09, 2019:

Hi Linda. Great website! I live on a houseboat in an isolated area up the BC coast a bit and I have a hydrophone under the boat..about 20 ft down. I got it originally so I could listen to the Humpbacks and the Orcas but very quickly found that there is a whole lot of stuff going on. It took me many months to finally find out about midshipmen, thanks to your site and others. There is one sound that I cannot identify and neither could Rhode Island. It sounds absolutely monstrous and demonic. I was wondering if you have an email address that I could send some recordings to so you could have a listen.

Linda Crampton (author) from British Columbia, Canada on August 04, 2017:

Thank you, Shruti.

Linda Crampton (author) from British Columbia, Canada on June 28, 2017:

Thanks for sharing your interesting idea, Alain. It's certainly intriguing to think about how other organisms might communicate.

Alain Lafume on June 28, 2017:

Pretty interesting that fish can use a variety of ways to make sound and communicate with each other. I always thought fish had a silent way of communicating because the sound they make are barely noticeable to humans.

This opens up a new avenue in my opinion about how much sound is a baseline way for many organisms in general to communicate. I wonder if we found alien organisms that live in the vacuum of space, how would they be able to communicate? I'm guessing through a series of pulse light emission glands. Very interesting indeed how many organism can have very similar baselines.

Linda Crampton (author) from British Columbia, Canada on March 14, 2017:

Thanks for sharing the information, Kytsune. It's interesting to discover the sounds that different fish make.

Kytsune on March 14, 2017:

Nice to hear some FRTing herrings. Schools of 'baitfish' produce a similar 'shimmering' clicking or ticking noise as they move together through the water. I snorkel so I don't have scuba gear interfering with my underwater hearing. The most difficult thing in water is to determine the direction from which the sound is coming.

Linda Crampton (author) from British Columbia, Canada on February 01, 2015:

Hi, nissantwa. It's interesting to hear about your personal experience with drum fish!

nissantwa on February 01, 2015:

Thanks. We live on a canal and the drum fish noises reverberate through the house at night. Seasonal but annoying.

Linda Crampton (author) from British Columbia, Canada on August 26, 2014:

Hi, ArtByLinda. It is fun - and very interesting - to learn about the sounds that fish make! Thank you very much for the comment.

Linda Hoxie from Idaho on August 26, 2014:

I have often as a child imagined the goldfish talking. As an adult I have heard the sound of the catfish grinding his teeth together, angry that he has been caught. I had no clue so many fish talked. Great information and fun to learn!

Linda Crampton (author) from British Columbia, Canada on June 02, 2013:

Thanks for the visit and the comment, PADDYBOY60!

PADDYBOY60 from Centreville Michigan on June 02, 2013:

Very interesting read. I used to love to catch Croakers just to hear them croak. :)

Linda Crampton (author) from British Columbia, Canada on May 30, 2011:

Thank you very much, CMHypno.

CMHypno from Other Side of the Sun on May 30, 2011:

Fascinating hub Alicia. It never even occurred to me before that fish made noises, so thanks for all the great information.

Linda Crampton (author) from British Columbia, Canada on May 25, 2011:

Hi, Movie Master. It's nice to meet you! Thank you for your comment.

Movie Master from United Kingdom on May 25, 2011:

Hi AliciaC what an unusual topic! a fasinating read and well explained, thank you

Linda Crampton (author) from British Columbia, Canada on May 22, 2011:

Hi, GetSmart. Thank you very much for the visit and your comment.

GetSmart on May 22, 2011:

Really great hub! I remember hearing about the black drum situation in Cape Coral. It got a lot of news coverage down here in Florida. Fascinating information. Thanks!

Linda Crampton (author) from British Columbia, Canada on May 18, 2011:

Thank you very much for the comment and the rating, Om Paramapoonya!

Om Paramapoonya on May 18, 2011:

What a refreshing topic! This hub has really changed my perspective about fish. Rated awesome. :)

Linda Crampton (author) from British Columbia, Canada on May 16, 2011:

Thank you, b. Malin! I'm hoping that researchers soon learn more about fish sounds and what they are used for.

b. Malin on May 16, 2011:

How very both interesting and fascinating...so fish can Talk, and now we can hear that sound...Wow, what next...Thanks Alicia, you always come up with Wonderful Hubs.

Linda Crampton (author) from British Columbia, Canada on May 16, 2011:

Thanks a lot, Chatkath. Yes, there is so much that we still need to discover about life in the ocean. It’s a very interesting topic!

Linda Crampton (author) from British Columbia, Canada on May 16, 2011:

Thank you very much, Tina. I find it interesting that two types of midshipman males have developed too!

Kathy from California on May 16, 2011:

You always write the most interesting hubs, this is no exception! I saw a show on this not too long ago, scientists were taping some of these sounds, but I didn't understand how they were able to make this noise until you did such a super job of explaining it! Thank you gor sharing, Rated up! So much in the ocean to still learn about.

Christina Lornemark from Sweden on May 16, 2011:

Amazing and informative article about life in the ocean! There is so much we don’t know about that hidden area of the globe. Interesting about the midshipman males and I wonder who will be most successful in the long run, type 1 or type 2?

Thanks for this fantastic hub Alicia! Voted up!

Linda Crampton (author) from British Columbia, Canada on May 16, 2011:

Thanks for the visit and the information, A.A. Zavala.

Linda Crampton (author) from British Columbia, Canada on May 16, 2011:

Thank you, ethel!

Augustine A Zavala from Texas on May 16, 2011:

We catch croakers on the coast, and the grunt and croak as you take them off the hook. Interesting.

Ethel Smith from Kingston-Upon-Hull on May 15, 2011:

This is an unusual hub. Excellent in fact

Linda Crampton (author) from British Columbia, Canada on May 15, 2011:

Hi, RTalloni. Thanks for the visit. Yes, we do have much to learn, but it's going to be a very interesting process!

RTalloni on May 15, 2011:

Neat hub! Discoveries like this tell us that we have much yet to learn. Thanks for the undersea investigation. I love being in the ocean!

Linda Crampton (author) from British Columbia, Canada on May 15, 2011:

Thanks for the comment and the vote, tillsontitan. I find it very interesting that fish have more abilities than scientists once thought!

Mary Craig from New York on May 15, 2011:

How interesting. Here I thought fish were the only "animals" that didn't make sounds! Well done! Voted up.

Linda Crampton (author) from British Columbia, Canada on May 15, 2011:

Hi, drbj. Thank you very much for your comment! I'm looking forward to more discoveries by the scientists who are researching fish vocalizations.

Linda Crampton (author) from British Columbia, Canada on May 15, 2011:

Thank you very much for the visit and the comment, breakfastpop.

drbj and sherry from south Florida on May 15, 2011:

Absolutely, positively fascinating, Alicia. Thank you for enhancing my scanty fish-vocalizing knowledge.

breakfastpop on May 15, 2011:

Simply fascinating. I never would have realized that fish can vocalize of not for this hub.