Scientists who surveyed Indonesia's Simeulue island near Sumatra after the killer earthquake two years ago discovered the temblor had raised the island by up to 4 feet, exposing most of the coral reefs ringing the island and causing one of the largest coral die-offs ever documented.

The study, by scientists from the U.S.-based Wildlife Conservation Society and the government-backed Australian Research Council Center of Excellence for Coral Reef Studies, reports an exposure of about 190 miles (300 kilometers) of sea floor, a news statement said.

"This is a story of mass mortality on a scale rarely observed," Stuart Campbell of the Wildlife Conservation Society's Indonesia marine program said. "In contrast to other threats like coral bleaching, none of the corals uplifted by the earthquake have survived."

Campbell said, however, that some sites in Simeulue were now recovering.

"At many sites, the worst affected species are beginning to decolonize the shallow reef areas. The reefs appear to be returning to what they looked like before the earthquake, although the process may take many years," he said.

The team said it had documented, for the first time in Indonesian waters, extensive damage to reefs caused by the crown-of-thorns starfish, a coral predator that has inflicted huge damage on reefs in Australia and other parts of the world.

"People monitoring Indonesian coral reefs now have another threat to watch out for, and not all reef damage should be immediately attributed to human influences," said Baird.

Indonesia has some of the richest reef environments in the world, but many have also suffered from human interference. The government has banned the use of chemicals such as cyanide and bombing to catch fish, but such practices still occur in many parts of the tropical nation composed of more than 17,000 islands.

(Agencies)