Beneath the waves, it's another world. Though, maybe it's not one that's quite so peaceful and hushed as it first appears — in fact, far from it. It's a veritable Babel down there. And whether they're warning of danger, calling for help, checking on neighbors, looking for a date or just scaring away the competition, as far as we can tell, around a thousand different kinds of noisy fish are joining in the conversation.
We took a look at six of the fish who have something to say.
1. Humming Midshipman
Photo Credit: Flickr, Ron Caswell
The plainfin midshipman (Porichthys notatus) is also known as the California singing fish. Found along the whole of the West Coast, the male attracts the female by humming — vibrating two specially developed "sonic muscles" very quickly against his resonant swim bladder like a drummer playing a drum roll.
Listen to the plainfin midshipman's hum in the video below.
To a human ear, the noise sounds more like the hum of an electrical generator than that of a prospective lover, but it seems to work. Once this noisy fish has been successful in his courtship, the male guards the eggs until they hatch while resuming his humming to find another mate. The atmosphere must be electric down there.
2. Squeaking Catfish
A study in 2010 showed that catfish (Siluriformes) communicate by squeaking to each other. This sound is actually a form of stridulation — the noise produced when an animal rubs one part of its body against another, like the chirping of crickets.
Listen to the featherfin catfish's squeaks in the video below.
This particular noisy fish rubs a section of its pectoral fin onto a ridged area at the base, either to warn of danger or to make its claim during mating and territorial face-offs. Who'd want to argue with an angry catfish?
3. Growling and Clicking Seahorses
A study at the Universidade Estadual da Paraíba in Brazil suggests that seahorses (Hippocampinae) growl when they feel threatened. Tiny vibrations led researchers to place underwater microphones (called hydrophones) near enough to longsnout seahorses (Hippocampus reidi) to pick up their oh-so-adorable audible reactions.
Listen to the seahorse's growl in the video below.
This response is thought to cause just enough alarm to allow escape from a predator. The briny equines also make clicking noises during the mating season — again, this is stridulation — by rubbing two sections of their skulls together.
And unusually for sea life, this behavior is found in both males and females trying to attract a mate. Presumably, they are each hoping to find a partner with whom they'll click.
4. Barking Toadfish
Toadfish hide out on the ocean floor, blending in perfectly with their background and posing a hazard to humans because of their poisonous spines. The three-spined toadfish (Batrachomoeus trispinosus) lives in the western Pacific Ocean and has a seemingly unique talent among sea creatures: It can create what is known as non-linear sound.
The toadfish has a swim bladder that is divided into two sections, and it creates its particular call by making a different sound with each half. These separate signals combine to produce a much more complex pattern of sound, one that scientists have compared to a foghorn or the alarm responses of meerkats, dogs and babies — meaning it's pretty hard to ignore.
Listen to the toadfish's "bark" in the video below.
So far, this noisy fish is the only known sea creature to have this ability, and the jury is still out on why. One thing we do know: There's no ignoring their call.
5. Booming Black Drum
Black drums (Pogonias cromis) live in the long stretches of water along the West Coast of the United States and, in the east, from Florida to Brazil.
During their mating season, the male drum attracts his mate by vibrating his sonic muscle against the swim bladder, creating the deep booming that gives the fish its name. Because of the low frequency of this vibration, the sound can travel quite long distances.
Listen to the black drum's "boom" in the video below.
Around 2005, some households in Florida with seafront access channels reported mysterious low-frequency throbbing sounds that kept them awake at night. It was later discovered shoals of black drum were congregating in these inlets and making big woo in the small hours.
6. Farting Herring
It isn't easy to admit, but it's not all "Finding Nemo" out there. A 2003 study suggests that herring (Clupea harengus) communicate in a rather unorthodox way.
By releasing gas from … the area you'd expect, the flatulent fish produce a stream of bubbles and a very high-pitched sound (around 22kHz — way beyond normal human hearing), courtesy of their swim bladders.
Listen to the buzzing produced by herring flatulence in the video below.
The researchers say cod also use air released from the swim bladder to communicate — but their frequencies are nowhere near as high as herring. It is suggested that the pitch is beyond the hearing range of most predators and allows these noisy fish to locate each other without giving away their position.
This technique has been dubbed "fast repetitive tick" — or FRT, for short. Anyone who tells you scientists don't have a sense of humor clearly doesn't read enough herring research.