The unfertilized eggs of the sturgeon have made the fish one of the world's most valuable wildlife resources. Some 90 percent of the world's caviar comes from sturgeon in the Caspian Sea, but uncontrolled fishing after the collapse of the Soviet Union has greatly reduced wild populations.
While nations around the Caspian (Russia, Turkmenistan, Kazakhstan, Azerbaijan and Iran) have agreed to ban sturgeon fishing, entrepreneurs elsewhere in the world are working on sustainable ways to harvest the expensive roe.
In Chungju, South Korea, one patient entrepreneur is claiming a 10-percent share of the global production of farmed caviar.
Along the banks of the Southern Han River, 50,000 captive sturgeon have found an ideal home.
The fish belong to former economist Han Sang Hun who, 17 years ago, brought a few hundred sturgeon back with him from a business trip to Russia.? "I believe that there is no other place that can provide an abundant amount of the right water for sturgeon. The river's level stays fairly constant here. So these waters are the ideal environment," he said.
One particular species of sturgeon swimming in these waters is the albino. And, its eggs are particularly precious. When they are put into cans like this one and auctioned in London they have fetched up to $40,000 per kilo.
"To produce superior caviar, the fish need to hibernate in water cooler than six degrees Celsius for 45 days during the winter," said Han Sung Hun.
Such attention to detail, spanning years of trial and error and patiently waiting more than a decade for the sturgeon to grow large enough, have allowed Han's fish farm to prosper.
The Korean caviar is harvested without harming the fish.
In other countries, the ancient and critically endangered beluga, which can grow to several meters in length, and live up to 150 years, are stunned or killed to find out if they have a stash of the lucrative eggs.
"Some [Russians] poke the fish with a screwdriver to see if they are ready to spawn and then drag the roe out. We do not need to do that because we discovered by accident how to feel their bellies to determine if they are ready to produce," said Han.
Han says he does not worry about potential competitors, whether they are in his back yard, where others have already tried and failed, or from other countries. Global conservation measures, strictly regulating exports, combined with an insatiable appetite among the wealthy, will keep demand for caviar far outpacing the supply.