TAIPEI: It may take a century at least for the coral reefs surrounding the outlying island of Lanyu to recover from the damage wrought by Typhoon Morakot, a researcher said yesterday.

"Morakot not only wreaked havoc on land in Taiwan but also on the corals on the seabed," said Chen Chao-lun, an associate research fellow at the Biodiversity Center of Academia Sinica, Taiwan's most prestigious academic institution.

"The seabed off Lanyu is littered with coral wreckage in the wake of the storm," Chen said, adding that the coral looks like it has been "shredded by a fruit slicer."

An avid amateur diver, Chen joined 55 other volunteers enlisted by two local environmental protection organizations to check the state of the coral reefs at 16 sites off the coasts of Taiwan proper and its outlying islands, between May and September.

"The live coral coverage in Lanyu waters used to exceed 50 percent, but the latest survey conducted after Typhoon Morakot showed that it has declined to 18 percent," Chen said. "This is a steep drop from the 69 percent recorded in 2004."

In what seemed to be a demonstration of the power of nature, Chen said, the storm uprooted from the seabed a six-meter-high coral that weighed nearly two tons and flung it across over a 10-meter-wide road onto the roof of the Lanyu Farmers Association, where it left a large hole.

In addition to natural disasters, overfishing is also a major threat to the survival of coral reefs in Lanyu waters, according to Chen.

A number of reef fish and shell species, including groupers, parrotfish and wrasse, have been greatly depleted, he noted. Overfishing has disrupted the marine food chain, a phenomenon that has made the Lanyu coral reef even more vulnerable to natural disasters, he added.

"A coral reef is like a community. When its fish and other living organisms are all poached or stolen, it becomes a community without protection and may collapse easily because it is so fragile," Chen explained.

According to Chen's estimate, it will take at least 100 years for the Lanyu coral reefs to regain full health and beauty, but only if overfishing and excessive development of coastal regions are halted.

The volunteers recruited by the Taiwan Environmental Information Association and the Taiwan Marine Environmental Education Association also surveyed the health of coral reefs at 15 other locations, including waters off Taiwan's northeastern coast and Taitung's Shanyuan beach as well as the outlying islands of Siaoliuciou, Green Island and Penghu's Dongyuping.

Chen, who has been studying and conserving Taiwan's coral reef ecosystems for more than 20 years, said he was pained by the post-Morakot situation.

"The waters off Shanyuan were filled with large pieces of driftwood that relentlessly battered the coral reefs, while silt and mud from the Bainan Stream flowed into the sea day and night, exacerbating the situation," Chen said.

The latest survey has found that live coral coverage at 12 of the 15 sites under study has fallen to below 25 percent, Chen said.

Like Lanyu, Green Island used to boast rich coral reef resources and over 50 percent live coral coverage, but that rate has fallen to 45.1 percent since the typhoon, from 64.2 percent in 2004," he added.

"The Siaoliuciou situation is even worse," Chen said. Overfishing, pollution and tourism have brought about irreversible damage to the coral reefs in that area, where the live coral coverage has remained below 20 percent since 1998, he said." The state of the coral reefs in the Siaoliuciou area is the worst and the ecosystem is unlikely to recover," Chen said, adding that recovery of marine resources starts with soil and land conservation.

China Daily/CNA

(HK Edition 11/03/2009 page2)