Conservation and marine experts from 63 countries have urged the United Nations to establish a moratorium on deep-sea fishing vessels that drag huge nets along the sea floor - a method considered 'most destructive' against coral forests and reefs.

The 1,136 scientists yesterday issued a joint statement - in conjunction with the ongoing UN Convention on Biological Diversity in Kuala Lumpur - calling on governments to protect vulnerable deep-sea eco-systems.

"As trawlers become more technologically sophisticated, and as fishes disappear from shallower areas, trawling is increasingly occurring at depths exceeding 1,000m," they said.

The recent discovery of dense, undersea coral forests has added urgency to their warnings. Such forests have up to thousands of species, including some resembling tall trees.

Reacting to the call, environmental group Greenpeace today urged governments attending the convention to pass a resolution recommending that the UN General Assembly adopts an immediate moratorium on high seas bottom trawling.

"Bottom trawling in the deep-sea is like clear-cutting a pristine ancient forest. Each trawl destroys everything in its path. In the interest of catching a few fish, hundreds of species - some of which have not even been identified - are destroyed," said Thilo Maack.

"Unfortunately, just as scientists have begun to understand the diversity, importance and vulnerability of deep-sea coral forests and reefs, humans have developed technologies that profoundly disturb them."

Corals are living animals that can congregate in spectacular colonies towering up to three metres tall. These minute animals are extremely slow growing - less than one inch a year - and are ultra-sensitive to disturbance.

Coral reefs and forests are considered to be the cradle of life for other marine species. They provide shelter from strong currents, protection from predators, nurseries for young fish, feeding and spawning areas, and breeding areas.