The New International Encyclopædia/Sturgeon
STURGEON (AF. sturjoun, OF., Fr. esturgeon, Sp. esturion, It. storione, from ML. sturgio, sturio, from OHG. sturjo, sturo, Ger. Stör, AS. styria, stiriga, sturgeon; perhaps connected with OHG. stōran, Ger. stören, AS. styrian, Eng. stir). A large fresh-water fish of the ganoid family Acipenseridæ. Sturgeons have an elongated, subcylindrical body, armed with five rows of bony plates or bucklers, each bearing a median keel. The head is covered by bony plates joined by sutures. The snout is produced; the mouth is inferior, opening on the under side of the head, protractile and without teeth. Just anterior to the mouth there are four barbels. The tail has the upper lobe much larger than the lower. There is a single dorsal fin, placed like the anal fin far back. They have a large air bladder, connected by a tube with the œsophagus.
|A FOSSIL STURGEON.|
|A long-beaked sturgeon (Belonorhynchus striolatus) fossil in the Trias and Lias formations of the Old World.|
About 25 species, in two genera, are recognized, all inhabitants of the fresh waters and seas of the northern regions. Most of the species are migratory and ascend streams to spawn, but some live permanently in fresh waters. They spawn in the spring and summer, and are very prolific, a large female producing from two to three million eggs, constituting from a fifth to a third of its entire weight. They feed on small animals and plants, which they suck into their mouth.
The common sturgeon (Acipenser sturio), of the coasts and rivers of Europe and Northeastern America, has been known to weigh 500 pounds. The lake or rock sturgeon (Acipenser rubicundus), once very abundant in the Great Lakes and the Mississippi Valley, attains a weight of 200 pounds, but the average is much less. Its sides are reddish, often with irregular blackish spots. Very peculiar in its prolonged paddle-shaped snout is the ‘shovelnose’ or ‘white’ sturgeon (Scaphirhynchus platyrhynchus), which is pale olive in color and about five feet long. It is a denizen of the Western and Southern States. Similar species occur in Asia. The largest of American sturgeons is that of the Pacific Coast (Acipenser transmontanus) called ‘white’ in comparison with the rare ‘green’ sturgeon (Acipenser medirostris). The former weighs 300 to 600 pounds, and is used as food, but the latter, which is nearly as large, but olive green, is not eaten. A giant beside these is the great Russian ‘bielaga’ or ‘huso’ (Acipenser huso), which has been known to attain a length of 20 to 25 feet and a weight of 3000 pounds. It is this species, once extremely abundant in the Danube, Volga, and other large rivers emptying into the Black and Caspian seas, which has furnished mainly the salted roe called caviar (q.v.), though some comes from the diminutive sterlet (Acipenser ruthenus) of the same region. The air bladder is also utilized for making isinglass.
Fossil sturgeon remains indistinguishable from the corresponding portions of the skeletons of modern species have been found in rocks as old as the Eocene. Earlier less specialized ancestral forms are Chondrosteus of the Jurassic and perhaps also the still older Palæoniscus of the Permian and Cheirolepis of the Upper Devonian. See Chirolepis; Chondrosteus; Palæoniscus.
|STURGEONS, PADDLE-FISH, AND BOWFIN|
|1. SHOVEL-NOSED STURGEON (Scaphirhynchus platyrhynchus).|
|2. PADDLE-FISH (Polyodon spathula), side view.|
|3. PADDLE-FISH, ventral view.|
|4. LAKE STURGEON (Acipenser rubicundus).|
|5. COMMON STURGEON (Acipenser sturio).|
|6. BOWFIN (Amia calva); In proportion to the other figures much enlarged.|