"Concordance was perfect"

At the Science Times, an appealingly lively article by Nonny de la Pena on the sounds fish make:

The most definitive tome on fish sounds was published in 1973 by the auspiciously named Marie Poland Fish and William H. Mowbray. Working at the Narragansett Marine Laboratory at Rhode Island University, they were granted access to Navy audio recordings made to detect enemy submarines. Because noisy underwater life kept interfering with the military’s objectives, the authors were asked to tease out the biologic from the manmade. The resulting work, “Sounds of Western North Atlantic Fishes: A Reference File of Underwater Biologic Sounds,” identifies the vocalizations of over 150 fish.

For most fish, the sonic mechanism is a muscle that vibrates a swim bladder not unlike our vocal cord. The bladder is a gas-filled sac used for buoyancy, but it can also be used as a sort of drum. The Gulf toadfish contracts its sonic muscle against its swim bladder thousands of times a minute to generate a loud drone. At nearly three times the average wingbeat of a hummingbird, toadfish have the fastest known muscle of any vertebrate. Cusk eel rattle bones against their bladder, but clownfish have a sonic ligament they use to “chirp.”

Other fish use stridulation, rubbing their bones together in a way that is comparable to plinking the tines on a comb or using a ratchet mechanism on their pectoral fins to make sounds. Herring release bubbles from their anus in a “fast repetitive tick.”

Good sound files, too.