Loudest Sex Ever? Fish's 'Machine Gun' Mating Call Could Deafen Dolphins

A species of Mexican fish called the Gulf Corvina boasts of an amazing sexual practice. These fish band together in gargantuan groups of gills and fins to form huge reproductive orgies that get so loud that it can deafen other sea animals.

The mating call of these red-listed fish have been recorded for the first time and can be heard here.

The sound made by a male Corvina resembles gunfire. This sound has been described as "a really loud machine gun" sound with multiple, rapid sound pulses.

The team found that these short bursts of sound were so loud that they could possibly cause hearing loss in the larger fish preying on these unique and endangered animals and even permanent deafness.

Every spring, the entire two million adult population of Gulf corvine who are ready to mate travel to a small area at the northern tip of the Gulf of California.

Here the mates engage in this mating call to attract females. On recording the sound the using underwater microphones called hydrophones, the team found that these fish can make sounds up to 192 decibels — enough to damage your eardrums if it were on land.

“It's louder than a rock concert,” says Brad Erisman, assistant professor at UTMSI and senior author of a study published June 13 in the journal Scientific Reports. “It’s louder than standing less than a meter from a chainsaw,” he added in a past press release.

All the world's adult Corvinas gather in less than one percent of their usual home range for a few weeks to mate.

These "spawning aggregations", as the scientists call it happens every year and this serves as an easy way to locate them. Along with this, the auditory frenzy which can get very loud leads trawlers and fishing boats directly to large colonies of fish amounting to at least a million individuals. This has led to a very wide scale opportunity for fishermen to make huge catches with lesser effort.

These sounds cause vibrations so strong that they can be even felt on the hull of the fishing boats in the area. These machine gun like calls can be heard even above water—drawing in the fishers faster and in higher numbers every year.

An adult Corvina can grow up to a meter in length and weigh an average of 26 pounds. These make them a prized catch in such high numbers. A reducing species size points to capture before they reach a full size which is a sign of overfishing.

Each spawning cluster has at least two million fish each during the season are caught in large numbers by fishermen putting the future of these loud lovers in peril.

An exact estimate of the population is not available because most of their habitat is murky water. During the frenzies, scientists use microphones or just their ear to locate these large schools.

They hope that this unique sexual practice could help researchers guide fishing boats away from schools of these mating Corvinas in the future. The fish cannot be seen in the dark, muddy waters, making them hard to count.

The frequency of the sound produced by the Corvina was found to be within the hearing range that could cause hearing loss in of seals, sea lion, and dolphins, or even deafen them, said the study.

Weird mating rituals in animals are seen across the board. Mammals, reptiles and even insects have weird rituals that help them create progeny. Female Preying Mantis is known to bite the heads of their male partners immediately after sex. The last thing the male does is procreate before the much larger female uses her super-fast hands and pincers to bite the head of the male.

In clownfish, only the largest male and the largest female of the school breed. The rest of the school are non-breeding males who wait their turn. If the largest female of the school dies the male will change sex and become the female and the next largest of the non-breeding males will get a promotion to become the breeding male.

The latest study about the sound level of the fish during mating season was published in journal Biology Letters.