Mexican fish orgies can deafen other sea animals

Species in danger from overfishing

Paris – A species of Mexican fish amasses in reproductive orgies so loud they can deafen other sea animals, scientists said yesterday, calling for preservation of the “spectacle” threatened by overfishing.

An individual spawning Gulf corvina, said the research team, utters a mating call resembling “a really loud machine gun”, with multiple, rapid sound pulses.

And when hundreds of thousands of fish get together to spawn once a year, “the collective chorus sounds like a crowd cheering at a stadium or perhaps a really loud beehive,” study co-author Timothy Rowell from the University of San Diego said.

“The sound levels generated by chorusing is loud enough to cause at least temporary if not permanent hearing loss in marine mammals that were observed preying on the fish,” he said.

Each spring, all adults of the popular eating fish migrate to a single site – in Mexico’s Gulf of California – for what scientists call a “spawning aggregation” that can number into the low millions.

During this time, male corvinas emit calls that reverberate through the hulls of fishing boats, and can be heard even above water – drawing in the fishers.

A fleet of some 500 boats nets as many as two million fish each spawning season, 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.

But there is evidence that landed corvinas are getting smaller – a sign of overfishing, which happens when fish of a particular species are caught faster than they can reproduce. –