Scientists in Russia have developed techniques for successfully farming "bester" (a hybrid of beluga and sterlet) and successfully harvesting the roe without killing the sturgeon.
Rather than being culled, like elsewhere in the world, the female fish is what can best be called “milked”, gently and harmlessly. Each time a fish is milked it can produce up to a quarter of its weight in caviar. This approach not only makes caviar more accessible but also helps preserve this increasingly scarce and beautiful fish... Russia halted commercial harvesting in 2002. Five years later, the sale of sturgeon and black caviar were banned altogether. Poaching escalated, and so did the prices. Now, the country is trying to return to the heady days of Soviet caviar abundance.
A video at the link illustrates the process, which appears to be similar to that used in this country at state-sanctioned fisheries and trout farms. The photo comes from English Russia, which has a photoessay with several recipes utilizing caviar.