When you first begin Scuba Diving one of the things that hit you straight away on your first couple of dives is the complete sensory transformation you experience underwater. Your sense of sight is impacted by the filtered light and the change in color spectrum throws you off, you feel a sense of weightlessness underwater and sound seems to disappear almost altogether with the exception of the constant whooshing of your breathing apparatus and bubbles which seem to be the only sound you hear…or is it?
The Coral Reef if you listen carefully is a true cacophony of different sounds created by the fish and marine inhabitants of the reef ecosystem. Apart from the Exhaust Bubble noises created by the divers themselves here are a few sounds that are commonly heard by scuba divers while diving a coral reef.
Crunching of parrot-fish
Parrotfish are perhaps one of the noisiest inhabitants of the reef. This fish has a strong beak that resembles the beak of a parrot, giving it its name. Parrotfish feed off Algae and coral, will scrape algae from the surface of the coral, creating a scraping sound so loud that you can hear it when you swim nearby underwater. You can often also hear the crunching or grinding sounds of a nearby parrotfish chewing away at coral skeleton trying to get at the coral polyps inside.
Shrimp Crackling or Popping (pistol Shrimp)
Pistol shrimp are tiny finger sized creatures that are seldom seen but almost always heard! Most popularly known with divers for their ceaseless cacophony that colonies of these shrimps produce; these shrimp emit loud crackling sound almost as if a hundred people are cracking their knuckles at once. These shrimp possess an oversized claw and the action of rapidly opening and shutting the claw produces a loud cracking sound which produces a sort of sonic blast, the shockwave of which is sufficient to stun a passing crab. The sound that these foraging shrimp produce is so distinctive that divers instantly recognize the sound whenever they hear it. (For more on the Pistol Shrimp read: Snap, Crackle and Pop- The Pistol Shrimp Up Close>)
Yes even though it sounds strange, several species of fish produce sound through their swim bladder or Stridulation which is the sound produced when hard skeletal parts or teeth are rubbed together. Fishes such as drums and croakers have sonic muscles attached to or near to their swim bladder. These muscles, the fastest contracting muscles known in vertebrates, cause the swim bladder to contract and expand at a rapid rate, thus creating drumming sounds. Toadfish and Silver Perch are known to croak or groan and Marine catfishes are known to make a creaking sound often heard by catfish anglers. Most common in the reef however is the sound produced by Grunts. This species of fish has over 150 variations and is known as the Grunt because of the pig-like grunts they can produce with their pharyngeal (throat) teeth.
Dolphin & Whale Sounds
Dolphins and Whales utilize their blowholes and valves to produce sound, though mostly in frequencies that we cannot detect, however dolphins can emit a very wide variety of sounds and humans can only hear a small portion in the range that these marine animals produce. Divers can often hear Dolphin whistles, clicks or chirps while underwater and are fascinating to hear should you ever come across them.