About 1.5 million Gulf corvina meet every year in the muddy waters of Mexico’s Colorado River Delta to reproduce. At the height of this annual mating frenzy, a breeding behavior that scientists call “spawning aggregation," amorous males unleash a thunderous chorus of sound pulses that can be clearly heard up and down a 12-mile (19-km) stretch of the delta. In a study published in December 2017 in the journal Biology Letters, marine biologists from the University of Texas at Austin measured the communal courtship call at 202 decibels, with individual fish producing sounds as loud as 177 decibels -- the loudest sound made by a fish species ever recorded.
All together now:
- The frequencies of sound emitted by the Gulf corvina were considered powerful enough to damage the hearing of nearby sea lions and dolphins.
- The researchers described the sound as similar to “a crowd cheering at a stadium or perhaps a really loud beehive.” Some say it sounds like a lawnmower.
- The thunderous sound of Gulf corvina comes from their swim bladder, a gas-filled organ in the abdomen that is surrounded by “sonic muscles,” which strum the bladder when the fish contracts its abdomen.