The Probert Encyclopaedia of Nature

STURGEON

The sturgeon (Acipenser) is a large ganoid fish of the order Palaeonisciformes, family Acipenseridae. The species are exclusively inhabitants of the temperate zone of the northern hemisphere, found both sides of the Atlantic, and live either in fresh water or pass a part of the year in rivers to spawn. They are large sluggish fishes reaching a length of three meters, and live on worms, crustaceans and molluscs which they rout out from the bottom with their snout which projects far in advance of the small, toothless mouth.
The skeleton is gristly, not bony, which is partly compensated by the head being encased in hard, bony plates which continue in five longitudinal rows along the body. The tail is heterocercal, the upper lobe being much longer than the lower. The Sturgeon has a single dorsal fin placed far back, only a little in advance of the tail.
The sturgeon is a 'royal fish' in Great Britain, as decreed by an Act of Parliament of Edward II, but the lord mayor of London has claim to those fish taken above London Bridge.
About twenty species of sturgeon are known, half of which occur in Europe. The largest species is Acipenser huso which is found in the Caspian Sea, the Sea of Azov, the Black Sea, the Danube and surrounding areas.
Research Sturgeon