The Convention on International Trade in Endangered Species (CITES) will decide on proposals to change trade rules for 50 types of plants and animals, with big implications for managing fisheries, the logging industry and pharmaceutical firms.

"Whales, elephant ivory and other charismatic species will still be on the agenda, but the focus is moving to commercial species and wider economic and social issues," said Sue Mainka, head of the Species Program at the World Conservation Union.

"You can tell that governments are taking CITES more seriously. It used to be only environment ministries who were interested, now officials from fisheries and foreign ministries increasingly come too," she added.

China and the United States, for instance, want the 166-nation talks to tighten protection of the Chinese yew which is the main source of top selling anti-cancer drug paclitaxel.

And Indonesia wants to limit trade in ramin, one of southeast Asia's main export timbers, because of over-logging and habitat destruction. Mahogany, mainly from Brazil, was added to protected lists at the last CITES meeting in Chile in 2002.

"CITES is increasingly the focus of efforts to protect fish and timber species that are traded globally in profitable commodity markets," the U.N. Environment Program (UNEP) said.

BIOLOGICAL DIVERSITY

CITES is also one of the main forums where the world asks about how far to protect the planet's biological diversity.

Studies say millions of species - including rare plants that might cure human diseases - risk extinction in coming decades from habitat destruction and global warming. CITES now all but bans trade in 600 animal species and 300 types of plants - from cheetahs to orchids. It strictly limits trade in 4,100 animal species and 28,000 types of plants.

UNEP also says CITES should help Third World nations by ensuring that they keep profits from exports, helping wider U.N. goals to halve the worst poverty by 2015.

Fisheries could be among the most controversial in Bangkok.

The meeting will consider proposals to limit trade in the humphead wrasse of the Pacific and Indian Oceans and the great white shark which is traded for meat and trophies.

The wrasse is a delicacy from China to Singapore.

"Nations like Japan see the addition of any commercial fish species as a foot in the door - next will be cod or tuna," one diplomat said.

"CITES is addressing commercially valuable fish where 10 years ago it never did," said John Frizell at environmental group Greenpeace. The largest sharks - whale sharks and basking sharks - were added to protected lists in 2002.

Among other proposals, Namibia and South Africa want to restrict trade in hoodia, a plant used for thousands of years by southern Africa's San Bushmen because it suppresses the feeling of hunger when chewed and could be a treatment for obesity.