Coral Life Detect Bad Reefs

Baby corals and fish can smell the difference between good and bad reefs, according to a study based in Fiji.

When offered a choice of two water samples in the lab, the animals turned away from the stench of seaweed that invades depleted reefs, but were drawn to the smell of healthy coral.

It is the first time that corals have been shown to react over long distances to chemical "smells" in the water.

The findings suggest that controlling seaweed is key to repopulating reefs.

Once a coral reef has decayed and seaweed takes over, stopping fishing in the area may not be enough to bring the coral back.

"If you're setting up a marine protected area to seed recruitment into a degraded habitat, that recruitment may not happen if young fish and coral are not recognizing the degraded area as habitat," said Dr Danielle Dixson from the Georgia Institute of Technology, the study's first author.