paddlefish

paddlefish

paddlefish, large freshwater fish, Polyodon spathula, of the Mississippi valley, also called spoonbill or duckbill and named for its flattened, paddle-shaped snout. The largest specimens weigh well over 150 lb (67.5 kg) and reach 6 ft (183 cm) in length. The snout may be a third of the length of the body; it is equipped with sense organs that assist the fish in finding its prey of small crustaceans, which it strains out with gill rakers (see gill). Paddlefishes are primitive; unlike most modern fishes, they have skins with reduced scales, almost wholly cartilaginous skeletons, and upturned tail fins. They are uniform leaden gray in color. Valued as food fish, their greenish black eggs, like the more highly valued ones of the distantly related sturgeon, are used to make caviar. A Chinese species, Psephurus gladius, found in the Chang (Yangtze) River but now believed to be extinct, reportedly grew up to 23 ft (7 m) in length, though modern recorded individuals were about half that size. Paddlefishes are classified in the phylum Chordata, subphylum Vertebrata, class Actinopterygii, order Acipenseriformes, family Polyodontidae.

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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Paddlefish

 

(Polyodontidae), a family offish of the order Acipenseriformes. The skin of the paddlefish is bare or covered with small bony scales. The snout is broad, flat, long, and shaped like a paddle or sword. The jaws are armed with numerous small teeth. There are two genera, including two modern and two fossil species. The species Polyodon spathula is found in the Mississippi River, Lake Erie, and rivers in the southern USA. They are up to 2 m long and weigh up to 75 kg. They feed on worms, water insects, crustaceans, and water plants and breed from March to June. Paddlefish have local commercial significance. The species Psepherus gladius is found in China (in the Yangtze River). They are up to 7 m long. They are predators and have little commercial significance.

REFERENCE

Nikol’skii, G. V. Chastnaia ichtiologiia, 2nd ed. Moscow, 1954.

G. I. LINDBERG

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.