Caviar sturgeon from the Sea of Azov began reaching the tables of aristocratic and noble Byzantine Greeks in the 10th century, after the commencement of large-scale trading between the Byzantine Empire and Kievan Rus'. The main types of caviar are Beluga, Sterlet, Kaluga hybrid, American osetra, Ossetra, Siberian sturgeon and Sevruga. The rarest and costliest is from beluga sturgeon that swim in the Caspian Sea, which is bordered by Iran, Kazakhstan, Russia, Turkmenistan, and Azerbaijan. Wild caviar production was suspended in Russia between 2008 and 2011 to allow wild stocks to replenish. Azerbaijan and Iran also allow the fishing of sturgeon
HMS Sterlet (2S) under the command of Lt. Gerard Henry Stacpoole Haward. Four days later she unsuccessfully attacked a convoy of three merchant ships and a destroyer. The following day she was assigned a new patrol area and on 14 April torpedoed the German gunnery training ship "Brummer", leading to her sinking the following day. She was possibly sunk by the German anti submarine trawlers "UJ-125", "UJ-126" and "UJ-128" on 18 April. Alternatively, she may have struck a mine whilst returning to port. HMS Sterlet (2S) HMS "Sterlett" was a second-batch S-class submarine built during the 1930s for the Royal Navy. Completed in