Scientists were shocked after discovering that a species of small Mexican fish can produce sounds so powerful during breeding season that it is able to damage the hearing of certain marine mammals such as dolphins.

“It is the loudest sound ever recorded for a fish species,” says Dr. Timothy Rowell, a researcher at the University of San Diego and co-author of a study on the subject published in the journal Biology. “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.”

During the spawning season, the chorus formed by the grouping of millions of fish “resembles that of a crowd shouting in a stadium,” Rowell adds. A single male of this species of fish is able to make almost as much noise as some species of whales while measuring less than one meter.

The males of the species Gulf corvina are found during the spawning period in groups of about 1.5 million and produce the loudest chorus which has so far been measured in marine fish: 177 decibels. For comparison, the sound intensity level of a jet engine is 120 decibels at a distance of 32 m, which is loud enough to cause permanent hearing damage in humans.

The incredibly loud noise of their collective choirs is among the loudest animal sounds in the water, the Guardian reports. Only a few whales, especially the sperm whale with a sound level pressure of 236 decibels per sonar click, are louder, while the whistle signal of the bottlenose dolphin is measured at 138 decibels.

Loud orgies of Mexican fish could deafen dolphins, say scientists https://t.co/77MGSlqcua — The Guardian (@guardian) December 20, 2017

Researchers at the University of Texas noted in the report that during the spawning season in April and May, several million of the fish gather in the Colorado River Delta, the highest part of the Gulf of Mexico. The region is traditionally heavily frequented by these fish, and therefore it is often very noisy. During this time of intense reproductive orgies, the males start their calls, which are so loud that they reverberate in the hulls of small fishing boats and can be heard above water.

As previously mentioned, this incredible spectacle has its flip side, as the sound levels can cause, at least temporarily, if not definitely, a hearing loss in marine mammals that are busy in search of food near this group of fish. However, sea lions and dolphins are frequently observed in this area despite the risk of their hearing. Another problem of the noise produced by the fish is that it allows fishermen to locate them very easily, which has resulted in overfishing. A single boat, equipped with a net, can capture two tons of the fish in just a few minutes.