sturgeon

Large, primitive, bony fish with five rows of bony plates and chin barbels used for exploring the bottom of the water for prey.

Sturgeons take 6–25 years to reach sexual maturity. The population in the Caspian Sea is threatened by pollution and intensive fishing for caviar; there was a 75% decline in the catch 1984–94 and stocks fell from 142 million to 40 million between 1968 and 1998. It has been estimated that sturgeon will vanish from the Caspian Sea by 2007 as a result of poaching and smuggling of fish. Rising pollution levels and the damming of rivers also means that fewer sturgeon are returning to rivers to spawn. Some 90% of the caviar taken from the Caspian Sea is smuggled, and poachers often catch the females before they are mature enough to produce eggs, thus further decimating the stocks. In 1997, in an effort to preserve the species, all sturgeon valued for their caviar were added to the Convention on International Trade in Endangered Species (CITES) Appendix 2 (classed as vulnerable). In June 2001, Russia, Kazakhstan, and Azerbaijan agreed to stop sturgeon fishing in the Caspian Sea until the beginning of 2002 in an attempt to counter overfishing.

North American species include the Atlantic sturgeon Acipenser oxyrhynchus, over 3 m/10 ft long.

The beluga sturgeon Huso huso of the Caspian Sea can reach a length of 8 m/25 ft and weigh 1,500 kg/3,300 lb.