Dive ban in bid to halt bleaching of coral reefs

Thailand is closing dozens of dive sites to tourists after coral reefs in the Andaman Sea suffered damage linked to unusually high water temperatures.

More than half of southern Thailand's 15,000 hectares of coral reefs are suffering from bleaching of coral linked to warming seas, officials said.

"We will study the cause and effect and find a way to restore them," said Sunan Arunnopparat, director of the Department of National Parks, adding that the reefs will be closed across seven national parks.

He declined to say how many diving spots would be closed or how extensive the damage was to the reefs. He said diving sites where bleaching had spread to 80 per cent of the reefs would be shut for an unspecified period.

The coral bleaching - whitening due to heat driving out the algae living within the coral tissues - was first reported in May after a surge in temperatures across the Andaman Sea from the northern tip of Sumatra to Thailand and Burma.

Other parts of Southeast Asia have also suffered. An international team of scientists studying bleaching off Indonesia's Aceh province found 80 per cent of some coral species died between May and August.

Some blame unregulated tourism - walking on coral, mooring of boats over reefs and contamination of the Andaman Sea, though global warming is also seen as a cause.