Killer starfish threaten Great Barrier Reef

Crown-of-thorns starfish have a voracious appetite and waves of carnivorous starfish are eating their way through Australia's Great Barrier Reef - and sugar cane farming is being blamed.

Researchers at Australia's Institute of Marine Science (AIMS), just outside Townsville, Queensland, in north-east Australia, have mapped the pattern of destruction.

"Coral cover is half of what it was 27 years ago, coral cover is going down at an alarming rate." Dr Katharina Fabricius, coral reef ecologist and AIMS principal research scientist, told the BBC World Service programme Discovery.

She said the biggest culprit was the Crown of Thorns Starfish (COTs).

"There are three main sources for the coral decline, one is storms, however 42% is attributed to Crown of Thorns Starfish - and just 10% due to bleaching. This compares with 70% due to bleaching for reefs elsewhere in the world , such as in the Caribbean."

“Crown of Thorns are very fecund animals - each female can produce between five and 20 million eggs ”
John Brodie, James Cook University

Bleaching occurs when corals are stressed by changes in conditions such as temperature, light, or nutrients. They expel the symbiotic algae living in their tissues, causing them to turn completely white.

Australian scientists are now looking at ways to reduce the destruction wreaked by starfish, which have the ability to smother coral and digest the fleshy parts.

    

The Great Barrier Reef off the Queensland coast is home to a wealth of marine life

A UN team has arrived in Australia to investigate possible damage to the Great Barrier Reef by the mining industry.

Fears that coal exports and oil and gas exploration would jeopardise the reef prompted the Unesco delegation's visit.

Environmentalists have urged the government to suspend mining development until a government review is completed.

The reef is home to 400 types of coral and 1,500 species of fish.

The Great Barrier Reef, which holds Unesco World Heritage

status, lies off the coast of the state of Queensland, which is the

largest producer of coal in the country.

The Unesco team is scheduled to visit the reef for a week

before making recommendations to the World Heritage committee. They will

also meet members of the government.

Environmentalists are concerned that an increase in coal

production and the shipping traffic that would follow could affect the

Great Barrier Reef's World Heritage status.

They want the government to suspend all new developments

while a state and federal review of the health of the reef is carried

out.