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Coral SOS Signals

November 29, 2012

Seaweed-covered corals emit a chemical that entices goby fish to clean them.



Corals’ cleaning call.  I’m Bob Hirshon and this is Science Update.

Coral reefs may look like colorful rocks, but they’re surprisingly complex organisms. In fact, they can call in a cleaning crew when they need it, according to Georgia Tech biologists Danielle Dixon and Mark Hay in the journal Science. Hay says a type of seaweed is toxic to coral. But as soon as the seaweed touches it, the coral releases a chemical that attracts goby fish, which eat it off.

MARK HAY (Georgia Institute of Technology):

So they’re like little barbers that run out, and just eat enough of it so that it doesn’t touch the coral anymore.

The fish were even attracted to water taken from other coral reefs that had been been touched by seaweed – yet the seaweed alone didn’t interest them. That suggests the gobies weren’t just snacking, but defending the coral where they make their home. Hay says it’s the first known example of a species calling in a bodyguard with a chemical signal.  I’m Bob Hirshon for AAAS, the Science Society.

The Pacific atoll of Yap is fringed by coral reefs. (NOAA)