Ossetra dwells another type of sturgeon, Siberian sturgeon ("Acipenser Baerii"), which is farmed all over the world because it can adapt to a wider range of habitats. It begins to produce caviar faster than "Acipenser gueldenstaedtii". Throughout the entire history of black caviar consumption, reference to Ossetra was made only to the fish that was caught first in Imperial Russia, then the USSR, and now in the Russian Federation. Today, Caspian Ossetra is facing extinction in its native habitat. Farming sturgeon is the only way to continue the production of high-quality caviar. Continuous drastic declines in natural sturgeon populations over the
HMS Sterlet (2S) reload torpedoes for a total of a dozen torpedoes. They were also armed with a 3-inch (76 mm) deck gun. Ordered on 2 March 1936, "Sterlett" was laid down on 14 July 1936 in HM Dockyard, Chatham and was launched on 22 September 1936. The boat was completed on 6 April 1938. At the onset of the Second World War, "Sterlet" was a member of the 2nd Submarine Flotilla. From 23–26 August 1939 the 2nd Submarine Flotilla transferred to its war bases at Dundee and Blyth. On 8 April 1940 "Sterlet" left for a patrol in the Skagerrak, off Norway