Furry crabs may be healing Great Barrier Reef

Published Feb 05, 2013 11:09am

This undated handout photo obtained on Feb 5, 2013, shows a diver beside a three-metre Acropora hyacinthus (plate coral) infected with white syndrome as furry crabs off Lizard Island in Queensland. Furry crabs once thought to be damaging the Great Barrier Reef may in fact be helping save the world famous coral by stopping the spread of disease, a researcher said on Feb 5, 2013.  Scientists at Australia's James Cook University studied the impact of furry coral crabs on fragments suffering from white syndrome, a deadly disease which appears throughout the Indo-Pacific and causes coral tissue to disintegrate. - AFP Photo
This undated handout photo obtained on Feb 5, 2013, shows a diver beside a three-metre Acropora hyacinthus (plate coral) infected with white syndrome as furry crabs off Lizard Island in Queensland. - AFP Photo

SYDNEY: Furry crabs once thought to be damaging the Great Barrier Reef may in fact be helping save the coral by stopping the spread of disease, a researcher said Tuesday.

Scientists at James Cook University studied the impact of furry coral crabs on fragments suffering from white syndrome, a deadly disease that appears throughout the Indo-Pacific and causes coral tissue to slough off.

“I think the crabs are helping by consuming that tissue as it falls off and also by eating any of the other associated microorganisms that could thrive on that dead and dying tissue,” researcher Joseph Pollock told AFP.

Pollock said the crabs did not kill the disease, the cause of which is still unknown, but his study showed they significantly slowed its progress.

“It slows it by about three-fold,” he said, adding that the disease was often associated with warmer water temperatures.

“It could be that these crabs are giving it (the coral) a bit of a chance to stay alive until potentially those water temperatures could come down or the coral could put up a defence to stop the disease progression itself.”

Pollock, from the Queensland University’s School of Marine and Tropical Biology, said he had been working on what causes the destructive disease.

“It can kill two-metre, three-metre coral colonies that are decades old in a matter of just months,” he said, adding that it was a major threat and sometimes overlooked.

Australia is under growing pressure to step up protection of the Great Barrier Reef, a world heritage site, which has been damaged by the predatory crown-of-thorns starfish.

Conservationists also fear the reef is at risk from a gas and mining boom, resulting in increased coastal run-off and more marine traffic, and coastal development.

Pollock said there were links between white syndrome and factors such as warmer water temperatures and coastal run-off.

He added: “Once a crown-of-thorns starfish comes through, even the parts that are still left alive are still very susceptible to the disease...they are all sort of intertwined together.”

Pollock said his study at Lizard Island, about 240 kilometres north of Cairns, involved collecting healthy and diseased coral colonies, adding crabs, and observing the fragments for three weeks.

He said the researchers found the crabs were strongly attracted to colonies hit by white syndrome.

“This means that when a coral is infected with the disease, crabs from nearby coral colonies could migrate to the diseased colony, slowing the disease,” he said.

“This could be a very interesting feedback mechanism whereby these crabs help to slow coral disease on reefs.”


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Comments (1) (Closed)


abdussamad
Feb 05, 2013 09:49pm
Furry crabs sound delicious! Yummy!