Fish Radio has reported on how scientists are studying fish sounds to learn more about where they are and what they are doing.  Only about 1,000 sounds have been cataloged so far, among them the loudest fish in the world.

Every spring massive schools of a Mexican fish called corvina migrate hundreds of miles to the Colorado River Delta at the northern tip of Mexico’s Gulf of California for a spawning mob that can number into the millions. The spawning continues for two to three days, every other week, for three months.

A single corvina, which can be three feet long and weigh up to 27 pounds,  makes a mating call that resembles a loud machine gun with rapid sound pulses made by flexing muscles around the swim bladder. Here’s a sample –


The simultaneous drumming of hundreds of thousands or even millions of the fish is so loud it can damage the hearing of dolphins and other sea animals that are preying on the fish.

Also preying on the corvina are fishing boats. The mating calls reverberate through the hulls of the boats and can be heard above the water.

A single boat with one net can harvest two tons of corvina in mere minutes. A fleet of 500 can take several million of the fish, placing the  species in peril.

According to the International Union for the Conservation of Nature (IUCN), which keeps a Red List of species, the Gulf corvina is “vulnerable” to extinction.

Researchers are pushing for a cautious approach by fisheries managers to make sure the ocean’s loudest spawning spectacle is protected.