Washington, March 20 : Australian researchers have suggested that the voracious weed-eating rabbit fish might be the key to saving large sections of the Great Barrier Reef from devastation.
Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies and James Cook University researcher Professor David Bellwood insisted that new research had shown the herbivorous rabbit fish, which is capable of stripping an area of vegetation, could combat coral-stifling weeds.
"When a coral reef is weakened or damaged through human activity such as climate change or pollution or by a natural disaster like a cyclone, the coral will usually recover provided it is not choked by fast-growing marine algae," Prof Bellwood said.
"The problem is that over the years we have fished down the populations of fish that normally feed on the young weed to such a degree that the weed is no longer kept in check - it can now smother the young corals and take over," he added.
He said the chances of coral re-establishing itself after such an event were small.
However, in a video study in which different fish were observed grazing in overgrown areas of the reef, schools of rabbit fish (Siganus canaliculatus) were seen chomping away at 10 times the rate of other weed-eaters.
"To our surprise and disappointment, the fish that usually 'mow' the reef - parrot fishes and surgeon fish - were of little help when it came to suppressing well established weedy growth. Most herbivores simply avoided the big weeds," Prof Bellwood said. "Then, to our even greater surprise a fish we had never seen in this area before was observed grazing on the weed. The rabbit fish (Siganus canaliculatus), came out of nowhere and began to clear-fell the weed placed on the reef crest," he added.
He said that the brown, bland-looking fish had been ignored in the past but could now prove to be an important protector of the reef.
However, he added that all the various species have to be kept intact in the reef environment, ready to play their part in a salvage operation when it becomes necessary.
"In Australia these herbivore fish populations are still in fairly good shape, but around the world as the big predators are fished out, local fishermen are targeting the herbivores," he said.
"In Hawaii, the Caribbean, Indonesia, Micronesia and French Polynesia there are reports of serious declines in herbivore numbers of up to 90 per cent.
"By killing them, we may be unwittingly eliminating the very thing which enables coral reefs to bounce back from the sort of shocks which human activity exposes them to," he added.