The countries bordering the Caspian Sea have been given another three months to comply with measures to protect the beluga sturgeon.
Sturgeon numbers have been drastically reduced
The fish, which is an endangered species, is the source of much of the world's beluga caviar.
Wildlife protection officials meeting in Geneva said that Kazakhstan and Russia now had until June to work out a plan to conserve the fish.
They had been facing a possible ban on trading in the prized delicacy.
Environmentalists say the beluga sturgeon could be wiped out in a matter of years by overfishing.
In the past two decades, the population of beluga sturgeon has shrunk by 90% and extensive illegal fishing in the sea and in the rivers where the sturgeon spawn is continuing to reduce their numbers.
Under an agreement backed by the Convention on the International Trade in Endangered Species - or CITES - Kazakhstan and Russia agreed to take measures to stop poaching and to prevent overfishing.
They say they have done so, but CITES officials meeting in Geneva have apparently concluded they have not done enough, and they have given them a further three months to show they are making progress - or to face a possible ban.
But the spring fishing season when most of this year's catch will be taken has just begun and an US environmental campaign, Caviar Emptor, says the extension will allow the catch of beluga sturgeon to go ahead unimpeded.
Kazakh fisheries officials say that sturgeon numbers are no longer in decline so a ban is unnecessary.
The US government is also considering a ban on the import of beluga caviar to protect the sturgeon.
The US imports 60% of the world's beluga supply.