Like most sturgeons, the beluga is anadromous, migrating upstream in rivers to spawn. Their team successfully removed fossil field jackets which contained articulated sturgeons, paddlefish and bowfins. Ganoid scales are found in the sturgeons, paddlefishes, gars, bowfin, and bichirs. Like most sturgeons, the lake sturgeon is rare now, and is protected in many areas. Sevruga is the smallest of the caviar-producing sturgeons. Iranian caviar is collected from sturgeons near Bandar Torkaman. They are fused in blowfishes and absent in cartilaginous fishes such as sturgeons. Sharks, rays, sturgeons, bowfins, gars and the gar-like "Aspidorhynchus" made up the fish fauna. Currently, Italian caviar is obtained almost entirely from bred sturgeons. Kalugas are one of the four species of sturgeons to exist in the Amur River. The Acipenseriformes are an order of primitive ray-finned fishes that includes the sturgeons and paddlefishes. The roe is also used as an affordable alternative to the caviar produced by sturgeons. Like many other sturgeons, they spawn in the rivers inland from the coast. Stomachs of green sturgeons caught in Delta contained "Corophium" sp. True sturgeons appear in the fossil record during the Upper Cretaceous.