While Jacques Cousteau called it "the silent world," if while diving you have ever held your breath and listened, you realized that it's quite noisy below the waves with all those clicks and clacks. Because water is so much denser than air, sound travels more than four times faster, so it's difficult for us air-breathers to determine where the sound comes from. It seems to be all around us.
But we didn't know, at least until now, that most reef fish are communicating with sound. That's the findings of a recent study published in the journal Ichthyology & Herpetology by a Cornell University team led by ecologist Aaron Rice.
They investigated ray-finned fishes - groupers, puffers, parrotfish, in fact just about all reef fish - after noting their anatomy implied they could vocalize. They discovered that 175 families of ray-finned fishes (about two-thirds of all fish) either communicated with sound or were considered likely to do so. As with most other vocalizing animals, the majority of the messages tend to focus on attracting mates, guarding food sources and territories, or announcing their location.
So, next time you're diving, stop and listen. Your fish friends may be talking to you..