Given the significant depletion in sturgeon populations, sturgeon fishing has almost disappeared globally and exporting wild sturgeon is now banned. To counteract this depletion, sturgeon farming has expanded in recent years. China produces the most farmed sturgeon in the world (85%), mostly for meat. Caviar, on the other hand, is mainly produced around the Caspian Sea, in Azerbaijan, Iran, Kazakhstan and Russia, followed by the European Union.
Farming sturgeon to produce caviar is expensive, as the females mature late. Smaller species can only reproduce when they are between five and nine years old whereas the larger ones are only sexually mature when they are between eight and fourteen years old. In the past, the females were slaughtered to extract their unfertilised eggs, but current techniques allow them to be harvested without killing the fish. Small incisions are made in their abdomens and the eggs are then squeezed out.
© Shutterstock / Jamesbox - Removing eggs from a sturgeon
The eggs are then weighed and sieved to remove them from their egg sack. After they have been washed and drained, they are graded according to quality. This is judged by the firmness, colour, smell and taste of the grains. The caviar is then salted to improve its taste and enable it to be preserved for longer. The salt is thoroughly mixed with the grains of caviar, but only briefly, so that they retain their firmness. The caviar is then placed on a sieve to dry. Almost 5% to 6% of the eggs’ weight is lost during this process.
The caviar is then quickly canned to stop it collapsing. The grains are packaged in metal tins and sealed with an overlapping lid to let as much air out as possible. Those due to be exported generally weigh 1.8 kg. They are then re-packaged in smaller tins by retailers. The tins are transported in refrigerated lorries. Small amounts are sometimes shipped by air freight.