By Richard Black BBC science correspondent

Almost 90% of South-East Asia's coral reefs are slowly being destroyed by human activity, according to a report just released by an environmental research group, the World Resources Institute.

It says over-fishing and pollution are putting unsustainable pressure on these ecosystems and that losing reefs would have significant economic consequences for the region.

Human activity has taken its toll

The coral reefs of South-East Asia are said by conservationists to be the most important in the world.

Of the 800 different species of coral known to science, three-quarters are found in South-East Asian waters.

According to the World Resources Institute, they are also the most threatened reefs in the world.

Among the report's conclusions are that Singapore has lost nearly two-thirds of its coral - mainly due to land reclamation and intensive coastal development.

Economic damage

Around Malaysia, some reefs have lost 85% of their coral and over the last 50 years, half of all reefs in Indonesian waters have been degraded.

The picture is broadly similar for other countries in the region.

When the reef dies, so do the fish that inhabit it

When coral dies, so do fish and other creatures which live on the reef.

The World Resources Institute says that in the Philippines, for example, what used to be some of the richest fishing grounds in the world now yield a third as many fish as they used to, as coral is killed off by blast fishing and sediment flowing on to the reefs from eroded coastal land.

The report estimates that from fishing alone, reefs contribute $2.5bn annually to South-East Asian economies and says that unless the governments of the region protect coral properly, this income will dry up in the coming decades.