Several species of sturgeon are harvested for their roe, which is processed into the luxury food caviar. Some species inhabit freshwater environments exclusively, while others primarily inhabit marine environments near coastal areas, and are known to venture into open ocean. Most sturgeons are anadromous bottom-feeders, migrating upstream to spawn but spending most of their lives feeding in river deltas and estuaries.
The largest sturgeon on record was a beluga female captured in the Volga Delta in 1827, measuring 7.2 m (23 ft 7 in) long and weighing 1,571 kg (3,463 lb). Several species can grow quite large, typically ranging 2–3.5 m (7–12 ft) in length. Sturgeons are long-lived, late-maturing fishes with distinctive characteristics, such as a heterocercal caudal fin similar to those of sharks, and an elongated, spindle-like body that is smooth-skinned, scaleless, and armored with five lateral rows of bony plates called scutes. Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. dabryanus) may be extinct in the wild, and one ( P. The family is grouped into four genera: Acipenser (which is paraphyletic, containing many distantly related sturgeon species), Huso, Scaphirhynchus, and Pseudoscaphirhynchus. They are one of two living families of the Acipenseriformes alongside paddlefish (Polyodontidae).
The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early Jurassic period, some 174 to 201 million years ago.
Sturgeon is the common name for the 28 species of fish belonging to the family Acipenseridae.
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