Thailand closes dive sites to halt damage to reefs

BANGKOK (Reuters) - Thailand is closing dozens of dive sites to tourists after unusually warm seas caused severe damage to coral reefs in the Andaman Sea, one of the world’s top diving and beach resort regions, authorities said on Thursday.

Officials dump a Chinese-made T-69 armoured tank into the Gulf of Thailand, near the southern Narathiwat province August 9, 2010. The 25 decommissioned Thai-army tanks will form artificial corals to improve the marine ecosystems and increase fish stock in the area. REUTERS/Surapan Boonthanom (THAILAND - Tags: MILITARY ENVIRONMENT SOCIETY)

More than half of southern Thailand’s 15,000 hectares of coral reefs are suffering from bleaching, or the shedding of coral colours, a phenomenon caused largely by rising sea temperatures over an extended period, officials said.

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

“This is part of an effort to restore the reefs.”

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 percent 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 island to Thailand and Myanmar.

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

Marine conservationists blame unregulated tourism -- walking on coral, mooring of boats over reefs and contamination of the water in the Andaman Sea, a region of sparkling blue-green waters and pearl-white beaches that draws thousands of tourists a year.

But Sunan said global warming was at fault.

Between April and late May, sea surface temperatures in the Andaman Sea rose to 34 degrees Celsius or about 4 degrees C above the long-term average, according to the U.S. National Oceanic and Atmospheric Administration's Coral Hotspots website. (See: here)

Coral bleaching involves the loss or expulsion of single cell algae (zooxanthellae) which normally live within the coral tissue and give it a brownish coloration. Loss of the algae sees the coral skeleton become visible through the transparent tissue giving the coral a bleached white appearance.

Bleaching occurs when coral is under stress from high temperatures, strong light and low salinity. Coral can only recover from minor bleaching.

“We did not close all of the national parks, just some of the dive sites. Tourists can still go see the forests and the mountains in these parks,” Sunan said.

Writing by Ambika Ahuja; Editing by Jason Szep and Sanjeev Miglani