For the impoverished fishermen of the Volga Delta it is a rare chance to make a little money.

They fish in secret in the dead of night. Nearly everyone here is unemployed.

But fishing for sturgeon and their eggs is a state monopoly.

Caviar poacher - "How else are we meant to live?"

What the man pictured is doing is illegal. If he is caught he will be imprisoned and lose his property.

"The police are out to punish us", he told me, "but we need the fish to survive. How else are we meant to live?"

Caviar pirates

The authorities see it differently. Poaching has reduced the caviar catch to catastrophically-low levels.

Russia says it may have to stop exports.

The small-time poachers are only part of the problem.

Major Peresypkin: "It's not an equal fight"

The real problems come from the caviar pirates, the wealthy mafia clans who are trawling the sturgeon to extinction.

Major Valery Peresypkin of the local fisheries police says his job is an impossible one.

"It's not an equal fight, our guys can't compete with the big league poachers," he told me. "They can afford expensive equipment we can't. It's as simple as that."

The town of Astrakhan is the centre of the industry - caviar is everywhere.

At the fish market I was approached by a dealer and taken aside, away from the searching eyes of the police.

Huge profits

The dealer offered me a kilo of osetra sturgeon caviar for $45.

Caviar eggs - huge profits

On the international market this fetches a price somewhere in the region of $3,500. The margins for profit are huge and that is why crime is involved.

Russia's state-run fisheries industry has lost so much to the pirates that its catch this year will not be much above 60 tonnes.

Ten years ago they regularly harvested over 1000 tonnes.

The cost of the glittering black caviar eggs is becoming unsustainably high.

A rich man's luxury could soon disappear from the food halls of the West.