Weed-eating Fish 'could Save Reefs

[mrmoshe]

Weed-eating fish could save the world's coral reefs, an Australian scientist says.

Professor Dave Bellwood, of Townsville's James Cook University (JCU), said reefs were being smothered by a "green tide" of weed caused by nutrients from erosion, agriculture, sewage and development.

But fish dubbed the "gardeners of the reef", such as parrotfish and surgeonfish, could help determine the fate of the important ecosystems, he said.

"We are only just beginning to realise what a vital role these groups of fish play in keeping reefs clean, healthy and free of weed," said Prof Bellwood, of JCU's Australian Research Council Centre of Excellence for Coral Reef Studies.

"Remove them, and you as good as remove the reef itself. Without the fish to mow the weed, it soon takes over completely from the coral."

Prof Bellwood said a group of parrotfish could eat through 40kg of coral algae within a couple of weeks, preventing weeds from completely taking over a reef.

He said previous experiments which removed such fish from reef areas found its corals quickly became completely smothered by the aquatic pest.

But Prof Bellwood said new research aimed to identify which species of weed-eating fish could actually reverse algal outbreaks once they took hold.

"What we're finding is it's not just the traditional herbivores which can help the reef, but it's a whole range of things and that they're able to do things that parrotfishes sometimes can't," he said.

"We're starting to now find that we have to be a lot more careful in terms of protecting fish that we assumed weren't that important, because they may be important for reversing trends."

Prof Bellwood said finding the right groups of fish to clean the reef could mark the beginning of new and innovative industries.

"I could imagine people going around in mobile cages full of reef regenerating fishes," he said.

"The only thing we ever do with fish is take them out and cook them and eat them.

"We never realise that fish are our friends and that we can use them positively."

Edited March 13, 2006 by MallacootaPete