By Alex Ritson
BBC News reporter in Kazakhstan
The egg sacs from sturgeon are highly prized across the world
A fishing boat chugs along the Ural river into the Caspian sea.
The nearest town - in fact the only town for about 400 miles - is Atyrau.
This remote region of Kazakhstan is one of the most important places in the world caviar industry. But something has gone badly wrong.
A quarter of a century ago, Kazakhstan harvested around 1,100 tonnes of caviar each year. Last year, the caviar haul was just eight tonnes - not even 1% of the previous total.
Igor Tokayov, the captain of the boat. has seen much change in his time.
"I've been fishing here since 1974. Before that, my father and my grandfather fished here, so I know about the changes which have taken place," he says.
"One of the biggest changes recently has been the fall in the number of fish that we catch, especially sturgeon. That's what we get beluga caviar from. We can make a living from the Caspian at the moment, but if the numbers keep falling then who knows?"
According to myth, local fishermen used to rip the slimy egg sacs from sturgeon and feed them to their pigs.
By the eighteenth century, Russian aristocrats had developed a taste for the stuff and insisted on carting live sturgeon with them - which could be sliced open when fresh caviar was required - when they travelled.
In the days of the Soviet Union, the fishermen of Atyrau were obliged to hand their catch over to a government sanctioned cartel.
Whoever was in charge, the fishermen made a good living. But things have changed.
"We've been considering this problem, and even scientists from Kazakhstan, Azerbaijan and Russia aren't really sure what's going on," says Talgat Akhanov, chief executive of the Atyrau Balik caviar processing plant.
"They seem to think it's down to how much fish are in this part of the Caspian sea, and whether or not they choose to swim into the Ural river to reproduce. Perhaps the fish are going somewhere else to breed and lay their eggs now."
But Shannon Crownover, who works in Kazakhstan for the environmental group Caviar Emptor, says political independence in the country following the collapse of the Soviet Union has removed a crucial degree of protection for the sturgeon.
"Fishing is the main problem, because when the Soviet Union broke apart so did the regulations that monitored the species, and so overfishing is a major problem, illegal fishing is rampant," she says.
"The Caspian sturgeon is an ancient species which has almost been wiped off the face of the planet within the last two decades".
But as the caviar industry has declined, a new source of jobs and wealth has arrived that should more than take its place.
Beneath the Caspian seabed, are two enormous oilfields which are predicted to catapult Kazakhstan into the world's top ten oil producing nations.
Despite the traditional hostility between environmental groups and energy companies, Ms Crownover says their arrival is not necessarily bad news - even for the sturgeon.
"The natural resources which have been found in Kazakhstan by the oil industry are very important to the future of this country. I believe that the oil companies that are here want to do a good job," she says.
"Our concern is if overfishing continues. There are so few beluga sturgeon left in the sea that if there was an environmental catastrophe, like an oil spill, it could be the final nail in the coffin for beluga sturgeon."
Under a United Nations-backed plan, the five nations which border the Caspian - Kazakhstan, Azerbaijan, Turkmenistan, Russia and Iran to the south, have agreed to take a total of only four and a half tonnes of Caviar from the sea in 2005.
With the caviar market at an all-time high, that is worth around £3m a tonne by the time it reaches the exclusive food stores of Europe and the US.
Even though that is a lot of money, it is not even a fraction of 1% of the income that Kazakhstan is already enjoying from oil.
No-one knows exactly how much crude is waiting to be pumped out, but Talgat Imangaliev, of oil firm Tengiz Chevroil, says the wealth generated by energy companies is already transforming the lives of people across Kazakhstan.
"Economics wise, it's one third of the county's revenue, that's how much the petroleum industry brings this country."