"The Silent World" is Far from Silent

Jacques Costeau was wrong about one thing. The oceans aren’t “The Silent World,” as he entitled his world-famous 1956 documentary. In fact, some 1,200 species of fish produce sounds – some uncomfortably audible to the human ear.

(The New York Times explored the topic of fish communications a few days ago, including a fascinating demonstration of the sounds produced by various sea creatures. This post summarizes the main points of the full Times article.)

A couple of years ago, residents along the peaceful Gulf Coast canals and estuaries of Cape Coral, Florida, were baffled by a mysterious racket penetrating their homes. That is, until a marine scientist named James Locascio told them they were hearing the mating call of a fish called the black drum.

“The most vocal and persistent complainers said there was no way a fish could produce a sound that could be heard inside a house,” he told the New York Times. “Black drum have taken a liking to the canal system in Cape Coral, and their nightly booming is like a water-drip torture that lasts for months.”

According to the Times, the same thing happened a few years ago in Sausalito, California, caused by the toadfish (at left). The local newspaper editorialized: “We don’t believe for an instant that the drone keeping Sausalito houseboaters awake at night is caused by a bunch of romantic toadfish humming their version of the Indian Love Song.” But it was.

The Times also quotes retired high school science teacher Greg Coppa, who heard noisy fish in Rhode Island. “Some people even asked what I drank before hearing the sounds or gave me that look reserved for a good, but pathetically impaired, friend.” Coppa believed he was hearing a huge fish, but it turned out to be the striped cusk eel – a tiny creature with the voice like a jackhammer.

Perhaps strangest of all, researchers at the Scripps Institution of Oceanography in San Diego recorded fish “chorusing” along 70 miles of the California coast, much like a “wave” at a stadium where fans stand and cheer like a wave moving along the bleachers. The aquatic chorus was transferred from fish to fish nearly five times as fast as sound travels in air.

Most fish create sounds by vibrating a gas-filled bladder thousands of times a minute – up to three times as fast as a hummingbird’s wings - while others bang bones against the bladder or just plink different bones together like the teeth of a comb. Other species have kept their audio mechanism a secret despite countless meticulous dissections.

“They have a fairly sophisticated mechanism of sound communications, with different meanings depending on the social context of the sounds,” says Andrew Bass, a professor of neurobiology at Cornell. “Sound communications probably first evolved among fishes.”