"The WTO has a once-in-a-lifetime chance to demonstrate that it can not only balance trade and the environment, but make one of the greatest contributions to protecting the world's oceans," said one of the signatories, Andrew Sharpless.

He called on Lamy to use his "skill and leadership" to ensure that this was achieved.

The declaration, sponsored by marine conservation professor Daniel Pauly of the University of British Colombia and marine biologist Boris Worm from Nova Scotia's Dalhousie University, both in Canada, was signed by 125 scientists from 27 countries.

Talks on fish subsidies are part of the WTO's Doha Round of global negotiations on lowering barriers to trade in goods and services which were launched in 2001 but are bogged down in disputes on agricultural support and goods tariffs.

"The WTO needs to seize the opportunity presented by the fisheries subsidies negotiations to address global overfishing because -- as the world's leading scientists have declared -- if we wait it will be too late," said Sharpless.

"It is up to the WTO to call a halt to this short-sighted race to capture the last fish in the ocean," added Sharpless, who heads the campaigning group Oceana.

Earlier this month, Oceana and the Swiss-based conservationist organisation WWF called on countries in the 150-member WTO to back a US proposal on ending subsidies that have boosted the size of world fishing fleets.

Scientific studies cited by both groups say the world's fishing stocks are in steep decline and could collapse within 50 years if current trends continue.

Total fishing subsidies, which include cash for research and stock management, are estimated at around US$34 billion a year, or a third of the sector's overall annual sales.