The tsunami unleashed on December 26 by a magnitude-9.0 earthquake off Sumatra island, which includes Aceh, left about 230,000 people missing or dead in the province.

Besides the untold human misery, officials say the quake and giant waves wrought havoc on the marine ecosystem, tearing up coral reefs and wiping out mangrove forests and seaweed beds along the coast.

Government experts and United Nations officials say it could take years and hundreds of million of dollars to restore the environmental damage to these backbones of the marine ecosystem caused by the natural disaster.

The UN Environmental Programme said the quake and the waves had damaged 25,000 hectares (61,750 acres) of mangroves, some 29,200 hectares of coral reefs and 120 hectares of seagrass beds.

The UN agency last week sent an expert to Aceh to address the environmental impact of the disaster.

Other teams are investigating the damage in the 10 other affected Indian Ocean countries.

Three teams from the Indonesian fisheries ministry are also in the region to determine what can be done to revive the fish farms along the northeast coast of Aceh, the main source of livelihood for over 10 percent of the region's population.

A UNEP report released last week put the environmental damage in Indonesia alone at 675 million dollars.

Indonesian officials say it could take up to five years to restore the marine ecosystem.

The environmental destruction is being felt hardest in the fish industries of Aceh's northeast coast that supply prawns, milkfish, and other seafood to the rest of the country and the region.

Fathuri Sukardi, an official at the fisheries ministry in Jakarta, estimates the damage to the sector at about 700 billion rupiah (about 76 million dollars).

"There was a lot of damage. The brackish water is gone, the infrastructure is gone, the irrigation canals. We also lost the hatcheries, probably 70 of them," Sukardi told AFP.

"It would take five years to rebuild the industry, and that would depend on the availability of funds," said the official, whose Aquaculture Development Center at Ujong Batee Point east of the provincial capital Banda Aceh lost most of its staff to the killer waves.

The assessment teams would also try to determine whether the damaged coast was still fit for fish culture, he added.

Environment Minister Rachmat Witular told the regional newspaper Serambi in an interview that it would take four years to restore the coastal environment to its pre-tsunami condition.

UNEP official Ben Claesen, who arrived in Banda Aceh last week, told AFP his team was still in the process of drawing up a more in-depth report on the destruction.

Replanting mangrove swamps which enveloped 1,625 kilometres (1,000 miles) of the north Sumatran coast until they were obliterated by the tsunami would be the first priority, Muhammad Adli Abdullah, an Indonesian consultant of the UN Development Programme, told AFP.

"There has to be a mangrove replanting to make the fish sanctuaries recover," he said, suggesting the UN or other aid agencies pay the more than half a million fishermen now out of work to restore the mangrove swamps.

"If we cannot there will be a big problem for the fishing community" of about 600,000 people, Adli said.

He said it would take two years "but we should start now".

The government also needed short-term measures to help feed the affected fishing community because of the tsunami's impact on their livelihood, he said.

While people could help restore the mangroves, there is little that can be done about the damage to the slow-growing coral reefs that are also important sanctuaries for fish and other marine creatures.

On the nearby island of Simeulue, officials said coral reefs had been pushed up above the water off the north coast, which had risen by more than a meter (three feet) due to the shift in tectonic plates caused by the quake.

Although there was some contamination of the waters by motor oil from vehicles and chemicals carried off to sea by the waves, experts said the damage was limited as Aceh and North Sumatra provinces are not very industrialised.

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