A 250 million year-old rite continues this week along the Russian rivers feeding into the Caspian Sea: The sturgeon are spawning as they have since the time of the dinosaurs. But this breeding season may be one of their last.

These ancient fish, prized for the unfertilized eggs of the females--that luxury product called caviar--are being devastated by overfishing, poaching, pollution, and industrial development. The World Wildlife Fund reports that the numbers of adult sturgeon in the Caspian plummeted from 142 million in 1978 to a scant 43.5 million in 1994. And scientists now fear that these unique and valuable fish may vanish from the region within five to 10 years.

FISHING FRENZY. At Bandar Anzali in northern Iran, sturgeon swimming into the rivers to spawn draw a crowd. But the fishery is strictly regulated here; Iran is the only remaining Caspian Sea country to maintain a state monopoly over the fishery.

Signers of the Convention on International Trade in Endangered Species (CITES) officially recognized the crisis when they met in Harare, Zimbabwe last June. Virtually all of the 29 sturgeon species found around the world today are threatened, and many have already disappeared; the American Great Lakes species died out earlier in this century. Those in the most danger, though, are three Caspian breeds--Beluga (Huso huso), Russian sturgeon (Acipenser gueldenstaedti) and stellate sturgeon (A. stellatus). Unfertilized eggs, or roe, from these creatures make up 90 percent of the world's most prized varieties of caviar.

Before 1991, the Soviet Union and Iran--the only two nations then bordering the Caspian Sea--regulated sturgeon fishing rigorously, ensuring a steady supply of caviar and the survival of the sturgeon in the region. In particular, they restricted fishing to the rivers into which the sturgeon return to spawn; taking fish on the open sea, where they mature, was prohibited. Thus, those that were born, or spawned and survived to make it back to the safety of the sea, were likely to return again to the rivers.

But when the Soviet Union collapsed, three new states--Azerbaijan, Kazakhstan and Turkmenistan--acquired Caspian shores. And these countries have been slow to put similar protective measures in place. (Azerbaijan applied to the CITES treaty only in April of this year--when the state fishery, Azerbalyg, banned black caviar export until they did so.) Increasingly fish have fallen prey to poachers in the past seven years.

Image: J.H. MACBRIDE, Cornell University
BAKU, AZERBAIJAN is the boomtown of the current "oil rush." Its harbor, shown here, is one of the most polluted bodies of water in the world. As the pace of offshore exploration picks up and more wells, such as those visible in the background, are drilled, experts expect stress on the sturgeon population to increase.

At the same time, the fishes ability to survive is being threatened by increasing levels of pollution. Pollution is not a new problem; Russian factories have flushed harmful sewage and industrial waste into the Caspian--a closed body of water roughly the size of California--since the 1960s. But countless new plants cropping up on the Caspian's shores--1,200 or more in Kazakstan alone--have made matters much worse. Baku, the capital of Azerbaijan, pumps some 250 to 300 million cubic meters of sewage into the Caspian annually. And the country is home to some of the globe's most polluted cities.

Moreover, many fear the outcome when offshore oil drilling starts in the Caspian in earnest. By most estimates, some 200 billion barrels of oil--about $4 trillion worth--lies beneath the Sea. Before 1991, the Soviet's did little to develop these reserves, choosing instead to focus on their established Siberian wells. But now oil companies from every continent are scrambling to drill offshore wells and are laying down pipelines to transport oil and natural gas to the eager markets of Europe and Asia. This new "oil rush" is likely to further contaminate this shallow sea.

Ichthyologists report that many sturgeon already show signs of poisoning and disease. These fish have no natural prey, thanks to their bony exterior. But few these days are living to complete their normal lifespan of 150 years; although beluga have been known to grow up to 1.5 tons, the average catch now weighs in under 100 pounds.

CASTING NETS. Using nets to snare sturgeon at sea destroys males and immature fish along with the valuable gravid females. Environmental organizations estimate that the bulk of caviar reaching international markets is obtained through such illegal or unregulated fishing practices.

Perhaps more alarming is the problem of overfishing. Faced with economic hardship, many people living around the Caspian have resorted to poaching. Only Iran maintains a state monopoly over the industry. Elsewhere it is often described as a free-for-all. When Russia tried to crack down on poaching in 1996, a bomb killed 67 border guards and their families in Dagestan. In May last year, a police official working to curb the illegal caviar trade was murdered.

To be sure, the finned "living fossils" are fast money. A single fish can carry more than $500 worth of caviar, and there is no shortage of demand. The oldest European caviar trading company, Dieckmann & Hansen, estimated that the international market for black caviar in 1995 was 450 metric tons--220 shy of the legal production in Russia and Iran combined. And figures from the U.S. Commerce Department show that caviar imports have shot up 100 percent since 1991.

Sadly, the sturgeon are particularly vulnerable to overfishing because it takes them some 15 to 20 years to reach sexual maturity. Only adult females yield the oily treasure, but poachers--often with large nets--indiscriminately take males and youths too.

Nor are poachers careful to discriminate among species, which creates problems for those trying to enforce laws and conservation programs. In a 1996 paper in the journal Nature, Rob DeSalle and Vadim J. Birstein of the American Museum of Natural History described a new method based on the polymerase chain reaction (PCR) for identifying sturgeon species. Traditionally, dealers have gone by size, color, smell and texture alone.

When DeSalle and Birstein analyzed 23 lots of caviar bought primarily in gourmet food stores in Manhattan, they found five mislabeled tins. In three cases, a threatened species had been marked as one in less danger. This month, the U.S. Fish and Wildlife Service began a campaign against illegal caviar imports, and the group hopes to make information on the PCR technique available through the Internet so that consumer groups can run their own tests to spot illegal imports. Even so, the only future for sturgeon may be in captive breeding programs.