Stocks of the Mediterranean's giant bluefin tuna face collapse because fishing countries failed to cut quotas at an international conference last week, campaigners said.

Over-fishing to supply the sushi trade has decimated stocks of bluefin tuna in the Mediterranean over the last decade. Campaign groups and some countries, led by the US, have said only a complete fishing ban for up to five years can reverse the decline.

But at its 10-day meeting in Antalya, Turkey, the body charged with regulating bluefin catches -- the International Commission for the Conservation of Atlantic Tuna (ICCAT) -- broadly maintained the catch limit, a quota even its own scientists say is unsustainable.

'After this latest failure to act, our expectation is that the fishery will collapse,' Greenpeace oceans campaigner Francois Provost said.

Though ICCAT, dominated by the European Union's voting bloc, cut its 2008 quota by 1,000 tonnes to 28,500, the catch limit for next year's April-July season will rise slightly for some countries that did not fill their quotas in recent years so they can fish more.

ICCAT's own scientists have said stocks will only recover if the quota is cut to 15,000 tonnes.

'ICCAT has proved itself to be entirely incompetent and has failed again in its duty to sustainably manage our common marine resources,' said Sergi Tudela, head of fisheries at WWF Mediterranean.

Greenpeace estimates under-reporting, fishing past the end of the season, and the illegal use of spotter planes took this year's catch to 45,000 tonnes.

Spain, a country environment group WWF says has under-reported its bluefin catch, said a new ICCAT plan to trace tuna from fishing boat to final destination would help stamp out illegal fishing and under-reporting.

The half-tonne fish, which has been hunted since the time of the Phoenicians 3,000 years ago, migrates thousands of kilometres and can swim in excess of 70 km an hour. Reuters