If commercial sturgeon fishing continues at its current rate, international trade in caviar could be facing a partial ban by the middle of next year. Established quotas for catches are based on population estimates that are "at best a guess," says the World Wildlife Fund.

Head of conservationist group WWF's species programme, Stuart Chapman, revealed: "This is the last chance for countries to tackle the sturgeon crisis. Unless clear answers are provided by exporting countries on their sturgeon management efforts, an international ban on caviar could be introduced within six months for the most endangered species."

From 7-9 December, scientists will review annual export quotas from caviar-producing countries at a meeting of the animal committee of CITES (Convention on International Trade in Endangered Species), but the WWF is also blaming the Russian Mafia for driving the illegal, and highly lucrative, caviar trade.

Chapman explained: "The Russian Mafia are threatening the very existence of a species. Unless urgent action is taken, caviar will become a thing of the past."

All but two species of sturgeon have now been classified as endangered, and catches in the Caspian Sea, where 60% of the world's caviar is gathered, have fallen to less than 3% of their levels during the 1970s.

Fears exist however that, even if trading bans are enforced on sturgeon products, poaching would still continue to feed domestic markets in Russia and elsewhere: "A fishing ban will only stop the legal fishery, but the illegal fishing and black market will continue," said the WWF.

The WWF is campaigning for members of the caviar trade to fund sturgeon conservation initiatives and is asking governments to tackle the black market corruption that leads to illegal poaching.