Weed-Eating Fish 'Key to Reef Survival'
Source: The ARC Centre of Excellence for Coral Reef Studies
March 10, 2011
"Preserving an intact population of weed-eating fish may be vital to saving the world's coral reefs from being engulfed by weed as human and climate impacts grow.
A new study by researchers at the ARC Centre of Excellence for Coral Reef Studies has found weed-eaters like parrotfish and surgeonfish can only keep coral reefs clear of weed up to a point. After the weeds reach a certain density, they take over entirely and the coral is lost.
For some years researchers have pinned their hopes on the ability of weed-eating fish to keep the weeds at bay while the corals recover following a major setback like bleaching, a dump of sediment from the land, or a violent cyclone.
However the latest work by Dr Andrew Hoey and Professor David Bellwood at CoECRS and James Cook University shows that once the weeds reach a certain density, the fish no longer control them, and prefer to graze less weedy areas. "As a result, the whole system tips from being coral-dominated to weed-dominated," Andrew says."
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