UNITED NATIONS – Local dealers describe its taste as “extraordinarily smooth and buttery.” If a horn spoon heaped with beluga caviar accompanied your year-end Champagne toast, savor the taste. By next New Year’s Eve, even if you are willing to plunk down $7,000 to indulge 30 of your best friends with the delicacy known as “black gold,” you may have to downgrade to American sevruga or osetra.

The U.N. agency charged with protecting wild species announced yesterday that caviar exports from the Caspian and Black seas will be effectively banned in 2006 – at least until the producing countries come to a satisfactory and realistic agreement on fishing quotas meant to preserve the wild sturgeon population.

“This is a long time coming and not at all a surprise,” the primary owner of Caviar Etc., David Bess, said. His New York-based company, which specializes in Internet and mail order sales, carries more than 50 types of caviar, but yesterday he said he supported the Geneva based agency’s move, as the population of the desirable roe producers in the Caspian Sea has depleted by 90%, according to his own estimate.

“It’s a crime,” the Ukrainian-born Mr. Bess said. “I hear that less than 1,000 female beluga whales are left in the Caspian Sea.”

The main countries exporting wild sturgeon are Iran, which controls more than 70% of the market, Russia, Azerbaijan, Kazakhstan, Romania, Bulgaria, Turkmenistan, and Serbia and Montenegro. The dwindling marine population there, a result of poaching and illegal fishing – among other things – has led some New York dealers to contemplate heresy and begin selling locally produced stuff.

“Our sales of American caviar have doubled,” the assistant manager of the Park Avenue store Caviarteria, Cindy Walters, said. “We only sell the best in the market,” she said, but Caspian and Black Sea caviar is “extremely difficult to get at a good price.”

And now the secretariat of the Convention on International Trade in Endangered Species of Wild Flora and Fauna, or CITES, has come down even harder on caviar producers in the regions of the Caspian and Black seas, the lower Danube River, and the Hilongjiang and Amur rivers on the Chinese-Russian border.

The Geneva-based agency in a statement yesterday expressed concern that the quotas proposed by the producing countries, “while lower than for previous years,” do not reflect the reality of harvesting caviar, and specifically do not account for illegal fishing.

These countries “must demonstrate that their proposed catch and export quotas reflect current population trends and are sustainable,” the secretary-general of CITES, Willem Wijnstekers, said in yesterday’s statement. “To do so they must also make full allowance for the amount of fish caught illegally.”

One diplomat from a caviar-producing country, who is familiar with past negotiations with CITES, said yesterday that the ban might not be the final U.N. word on the toothsome trade. “It was a similar situation two years ago,” said the diplomat, who asked not to be identified by name or country as he was not authorized to speak on the record.

At that time, he said, the producing countries could not come to a quota agreement among themselves. This time, the agency has not accepted the quotas agreed to by the producers but the result could be the same. “In the process of negotiations they could come to an agreement,” he said.

Mr. Bess said some of his colleagues perhaps do sell – illegally – the harvest of “mafia” fishermen in countries that produce the best caviar of beluga whales, which takes as many as 15 years to mature. That caviar, harvested from the Caspian Sea is best because of “the mineral content of the ecosystem” there, he said.

The Web site of the seller Petrossian describes beluga as “the most prized of all caviar due to its extraordinarily smooth and buttery taste.” Petrossian currently advertises the sale of 1 kilogram, or 35 1/4 ounces, of its “royal” beluga caviar, which serves a party of up to 32, for the price of $6,980.

Mr. Bess said he still has some reserves of beluga caviar left, but he would not say how long it will last or how much stock he has. If the U.N. ban continues, he added, reserves would not last for more than up to six months, as caviar does not preserve well. Other types of caviar, he said, including the sevruga and osetra, are less endangered, and therefore still available.