The United Nations needs to stop the destruction of deep sea ecosystems by banning fishermen from trawling nets on the ocean floor, Australia, New Zealand and Palau, joined by actress Sigourney Weaver, said on Tuesday.

The 192-member United Nations General Assembly is due to begin debating this week an Australian-led plan to ban deep sea bottom trawling in unmanaged high seas and impose tougher regulation of other destructive fishing practices.

The White House announced on Tuesday that it would support a ban on deep sea trawling, while the European Commission -- executive of the 25-member European Union -- declared its backing for the proposal last week.

U.N. General Assembly resolutions are non-binding, but they reflect the will of the international community.

About 64 percent of the world's ocean is in international waters, of which about three-quarters is unmanaged, according to the Pew Institute for Ocean Science.

"The world's oceans are facing a crisis," Weaver told a news conference, adding that deep sea bottom trawling was "raping these oceans beyond site and beyond regulation."

"I have come here to join everybody in appealing to all of those involved to do the right thing for the seas and for future generations, both human and aquatic, who will thrive on the bounty of the oceans if given half a chance," said Weaver, star of the movies "Alien" and "Ghostbusters."

'TRAGIC AND UNPRECEDENTED LOSS OF LIFE'

As mainstay species like cod and hake become depleted by overfishing, deepwater species with names such as forkbeard, orange roughy, black scabbardfish and roundnose grenadier are an attractive catch as trawlers move to new fishing grounds.

A bottom trawl is a cone-shaped net that is towed by one or two boats across the sea floor, as much as 1400 meters (4,600 feet) below the surface, its pointed end retaining all the fish that are scooped up.

It can cause damage to extremely slow growing ecosystems, particularly coral reefs, and also depletes other marine life that is captured by the nets.

"The global picture in relation to conservation of the marine environment is a dismal one," Australia's Ambassador to the United Nations, Robert Hill, said.

The organisms that live in the benthic regions -- on the bottom of the sea -- can survive without light and tolerate low temperatures. The World Conservation Union said between 500,000 and 100 million species are thought to inhabit these areas.

A Greenpeace report in March said that 40 percent of the world's oceans should be placed in nature reserves. Just 0.6 percent of oceans are protected reserves at present, compared with 12 percent of the world's land, according to U.N. data.

"We do know very little about the deep sea, but what we do know suggests that it is the largest, most biologically rich place on this earth," Ellen Pikitch, executive director of the Pew Institute for Ocean Science said.

"If the United Nations does not take action now, I believe we will see a tragic and unprecedented loss of life before we even have the chance to see it, to know it, to describe it."

Copyright © 2006 Reuters Limited

###