These Mexican fish are having such loud orgies, they're deafening dolphins

These Mexican fish are having such loud orgies, they're deafening dolphins

We all know someone who can be, ahem, noisy in the bedroom. And I'm not talking about the springs on the bed, if that's what you think I mean. The sound of someone enjoying themselves in "private" is fabulous for them, and fabulously infuriating for the rest of us. But, has your vocal flatmate ever deafened you? I'm guessing not. If this is the case, then you should count yourself lucky, because not everyone gets the privilege of preserving their eardrums when they overhear a nearby lovemaking session.

The individuals I'm referring to are the dolphins, sea lions, seals - and other sea life creatures - living near the Colorado River Delta. According to researchers, their neighbours, a species of Mexican fish named Gulf corvina, are indulging in orgies so loud that they can deafen other sea animals. Hilariously, the spectacle - which involves hundreds of millions of the spawning fish - has even been described as "among the loudest wildlife events found on planet earth" and it's been said that the mating call of a single Gulf corvina apparently resembles a machine gun.


So, how did this head-splitting orgy come about? Each spring all of the adults of the species migrate to a single site - a 16-mile strip (27 km) of the Colorado River Delta in the northernmost part of Mexico's Gulf of California - for what scientists call a "spawning aggregation". Amazingly, the frenzy sees pretty much all of the world's adult Gulf corvinas gathered in less than one per cent of their usual home range for a few weeks at a time.

It's then that the romps between the sheets, or the waves, begin. In 2014, marine biologists Timothy Rowell, from the University of San Diego, and his colleague Brad Erisman of the University of Texas, spent four days using specialised underwater sound gear to eavesdrop on spawning Gulf corvina, a fish regularly served up in restaurants. It was then that they discovered just how loud the world's loudest fish could be.

The researchers estimated the noise produced by a single Gulf corvina, from a standard distance of about a meter away, using three different measurements of individual sound levels. The highest measurement was 190 decibels (dB) using a peak-to-peak measurement, and the peak RMS (root mean square) was 177 decibels. Not to mention the collective volume of the aggregation was recorded at 163 dB at its peak. To put this scientific mumbo-jumbo into perspective, and gather exactly how loud this is, below is an audio clip of a group of males chorusing. In the foreground, an individual male can be heard swimming by, his ear-splitting chattering becoming progressively louder as he passes the microphone.

During the raunchy meet-up, male Gulf corvinas apparently emit calls that reverberate through the hulls of fishing boats and can even be heard even above water. The decibel rates reported seem incredibly high (which they definitely are), but it’s important to remember the fact that measurements of decibels in air and water are different. Researchers explained that the sound levels are so deafeningly high because water is more efficient at transporting sound pressure than in air. In addition to being loud, these fish transmit sounds faster and further than they would in air.

Speaking about their discovery which was published in Scientific Reports in December 2017, co-author Timothy Rowell said:

"The collective chorus sounds like a crowd cheering at a stadium or perhaps a really loud beehive. 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. These spawning events are among the loudest wildlife events found on planet Earth and the loudest sound ever recorded for a fish species.”


However, the fish, which can grow to about a metre (3.3ft) in length and weigh as much as 12kg (26lb), may want to think about quieting down their wild frolics given the fact that their boisterous sex isn't working in their favour. In fact, it's pretty much shooting them in the foot - or fin, should we say.

Once local fishermen hear the mating calls, they are drawn in and within minutes a single boat can have harvested two tonnes of the fish. According to the International Union for the Conservation of Nature (IUCN), which keeps a red list of endangered species, the Gulf corvina is “vulnerable” to extinction. No wonder, considering a fleet of 500 boats nets as many as two million fish each spawning season.

Although it's difficult for experts to keep tabs on exactly how much the population has fallen, there is evidence that landed Gulf corvinas are getting smaller - a sign of overfishing, which occurs when fish of a particular species are caught faster than they can reproduce. Ultimately their tumultuous fornication looks like it could be partly to blame for their downfall.

Dolphin Credit: Hamid Elbaz

While discussing the noisy fish, researchers stated that the spawning fest deserved “increased appreciation and conservation”, with Rowell stating: “A precautionary approach should be adopted by fisheries managers to ensure that this wildlife spectacle does not disappear."

So, at the end of the day, despite the Mexican fishes' passionate orgies being so loud there's a chance they could deafen the sea creatures around them, the real moral of our story isn't about rowdy sex. Instead, it's a reminder that we all need to pull together and ensure that all creatures on this planet are conserved in the way they rightfully should be.

That, and to thank your lucky stars that, although your flatmate may be loud in the bedroom, they're probably never going to deafen you with machine gun-like moans of pleasure.