Sturgeon, a family of large fish found throughout the Northern Hemisphere. Sturgeons are primitive fishes, having existed for at least 300,000,000 years. There are about 15 species, more than half of which are found in the United States. Some species live only in freshwater. Most, however, live in the sea and enter rivers to spawn. At one spawning, the female may produce 3,000,000 or more eggs.
Sturgeon eggs are used to make caviar; the flesh is also eaten. The sturgeon's air bladder is sometimes used to make a gelatin called isinglass. Once an important commercial fish, the sturgeon has decreased in numbers because of water pollution and overfishing. In many areas sturgeon is a popular game fish.
Most sturgeons are brownish, greenish, or grayish with light underparts. Sturgeons have no scales but have five rows of bony plates, called scutes, on the sides of the body. Bony plates also cover the head. The mouth, which has no teeth, is on the underside of the elongated snout. Sturgeons can protrude the mouth to siphon from mud or sand the small animals they usually eat. Hanging down from the snout, in front of the mouth, are four whisker-like barbels that serve as feelers.Sturgeons have no scales but have five rows of bony plates on the sides of the body.
Largest of the sturgeons is the beluga, which can grow up to 28 feet (8.5 m) long. This species is a source of the finest caviar. The beluga is found in the Caspian and Black seas and in the Volga River. The largest of the American species, as well as the largest freshwater fish of the United States, is the white sturgeon, which grows up to 12 feet (3.7 m) or more in length. It is found along the Pacific coast, and enters rivers to spawn. Some populations are land-locked and spend their entire lives in fresh-water lakes.
The lake sturgeon is found in lakes and streams of the eastern half of the United States and in Canada. It grows up to 7 feet (2.1 m) or more in length. The green sturgeon of the Pacific coast and nearby rivers grows up to 7 feet long. The Atlantic sturgeon, found on both sides of the Atlantic and in nearby rivers, grows up to 10 feet (3 m) in length.
Sturgeons make up the family Acipenseridae. The beluga is Huso huso; the white sturgeon, Acipenser transmontanus; the lake sturgeon, A. fulvescens; the green sturgeon, A. medirostris; the Atlantic sturgeon, A. oxyrhynchus.