Drumming Fish!

The Sound of LAUGHING FISH!

A few years ago, a friend of ours was wreck diving when all of a sudden she came face to face with a rather large 'grouper'. Locked in a fierce stare, the fish started to emit loud grunting sounds. Surprised by the sounds, our friend grunted back. Whereupon the fish seemingly decided that it had met its match and swam meekly away.

We know that cetaceans 'vocalize' - we've all heard the sounds of the humpback whale singing on prime time TV. But, it's estimated that perhaps half of all fish species also make sound. I know fishermen who swear 'the fish were laughing at us'. But, researchers around the world are just beginning to unravel the mysteries of fish sounds.

One such researcher is Dr. Joe Luczkovich at the Eastern Carolina University. He and his team have been working for several years trying to record and analyze the sounds of fish that live near the shores of North Carolina's Pamlico Sound.

Using hydrophones (underwater microphones), they 'hunt' for sounds - identify them - and watch for telltale signs of spawning activity. For it seems that much of the sound coming from the North Carolina fish have to do with attracting mates. The male generates a sound by vibrating his swim bladder to advertise his presence. And, perhaps, to warn off other males.

One of the problems that Dr. Joe is looking at is the decrease in the number of various commercial fish species along the North Carolina coast. Are they being overfished? Are their spawning grounds being made unuseable by pollution? Or, are boaters and other human activities unknowingly disturbing the courtship process?

Tracking fish by their sounds lets these researchers identify spawning sites. They have found that each species of fish makes different sounds. So, by listening to the sounds you can find a spawning area, identify which fish are there and even estimate their number. If it turns out (as is likely) that fish return to the same spawning spots year after year, these areas can be protected by law.

It seems easy, but its not. First, one has to identify the which sounds are made by what fish. In any body of water that can be difficult. One of the biggest problems is sorting through a large amount of un-identifiable sounds. The sea, or even a pond, can be a very noise place - underwater that is. Back in 1970, it was reported that over 200 species of fishes make some form of sound. Today, many researchers believe that between 30 and 50 percent of all fish 'vocalize'.

The sounds they make vary. You will hear 'grunts', 'drums', 'doorknocks', 'heartbeats' , 'burps', 'croaks', 'crackles', 'chattering', purring', 'clucking' and even a 'foghorn'!

Try these samples for yourself:

http://150.216.20.107/drumming/cn.wav
Heartbeat and Burp (126 kB WAVE) - Spotted Seatrout (Cynoscion nebulosus) Spawning males produce a "heartbeat" and a "burp" sound by vibrating their swim bladders.

http://150.216.20.107/drumming/wfpurr.wav
Purring (198 kB, WAVE) - Weakfish (Cynoscion regalis). Sound made by the drumming of the swim bladders in the males.

http://150.216.20.107/drumming/wfstuc.wav
Chattering (68 kB, WAVE) - Weakfish (Cynoscion regalis). A rapid clicking noise. This sound is produced by both males and females.

http://150.216.20.107/drumming/CynRegChor.wav
School sound (160 kB, WAVE) - Weakfish (Cynoscion regalis). This sounds like static, but it is an aggregation of spawning weakfish recorded after sunset.

http://150.216.20.107/drumming/bc_cluc.wav
Clucking (77 kB, WAVE) - Silver Perch (Bairdiella chrysoura). This is one of the most common sounds in North Carolina waters between April and September. Sometimes they only produce a few short clucks.

http://150.216.20.107/drumming/bc_chor.wav
Chorus or School (78 kB, WAVE) - Silver Perch (Bairdiella chrysoura). This is NOT 'static'. It is the produced by an aggregation of spawning silver perch. "We have recorded this as loud as 149 dB (re 1 microPa), this is a higher sound pressure level than a rock concert!"

http://150.216.20.107/drumming/opstau.wav
Fog Horn (840 kB, WAVE) - Oyster Toadfish (Opsanus tau). It sounds like a foghorn. The crackling you hear in the back- ground is shrimp. This sound was RECORDED FROM A PIER in Beaufort, North Carolina

http://150.216.20.107/drumming/micund.wav
Croak (236 kB) - Atlantic Croaker (Micropogonias undulatus). This is a croaker alarm call given off by a captive fish in shallow water in the harbor at Ocracoke, NC.

There is plenty of room for research on your part. Everyday more species are being recorder and identified. The 'identification' part isn't easy and the wide scale cooperation and sharing of sound recordings and observations is needed to help reduce the enormous task of identifying the 'mystery sounds' of the underworld. You don't need an ocean, or a boat. Wherever there are fish there may be strange new sounds to hear.

If you would like to learn more about this work have a look at: