beluga(redirected from Delphinapterus)
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white whale,small, toothed northern whalewhale,
aquatic mammal of the order Cetacea, found in all oceans of the world. Members of this order vary greatly in size and include the largest animals that have ever lived. Cetaceans never leave the water, even to give birth.
..... Click the link for more information. , Delphinapterus leucas. The beluga may reach a length of 19 ft (5.8 m) and a weight of 4,400 lb (2,000 kg). It has a small, round head, with a short, broad, beaklike snout, and a flexible neck; its flippers are short, broad, and rounded, and it lacks a dorsal fin. It produces a variety of noises and is sometimes called a sea canary. The young are born with dark fur but become almost pure white in maturity. Belugas winter in the Arctic Ocean, feeding upon crustaceans, fish, and squid; they are often found in groups of several hundred individuals. They mate in spring, and in summer they enter northern rivers. The young are born after a gestation period of 14 months, one calf every second year. The beluga is hunted by the Eskimo for food and by commercial whalers for its hide, which is known as porpoise hide. Beluga is also the common name of the largest of the sturgeonssturgeon,
primitive fish of the northern regions of Europe, Asia, and North America. Unlike evolutionarily advanced fishes, it has a fine-grained hide, with very reduced scalation, a mostly cartilaginous skeleton, upturned tail fins, and a mouth set well back on the underside of
..... Click the link for more information. . Beluga whales are classified in the phylum ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
..... Click the link for more information. , subphylum Vertebrata, class Mammalia, order Cetacea, family Monodontidae.
(Huso huso), a valuable commercial fish of the sturgeon family.
The beluga is up to 9 m long. It weighs up to 1 ton or up to 1.5 tons in exceptional cases. The beluga is distinguished from other sturgeons by its huge crescent-shaped mouth and fused branchial membranes. Beluga live in the Caspian, Black, Azov, and Adriatic seas, from which they enter the rivers. They reach sexual maturity at 12–18 years, when they are about 2 m long. They enter the rivers for reproduction, producing from 0.5 to 5 million eggs. When beluga are in the Volga two races are distinguished: the spring beluga (which enter the river in April and spawn in May of the same year) and the winter beluga (which enter the river in the fall and spawn in the spring of the following year). The beluga fry slip out to sea, where they feed on mollusks and crustaceans. The adults feed on various fish (roach, herring, gobies, anchovies, Black Sea haddock, and others).
The roe of the beluga is larger than that of other sturgeons and is used mainly in the manufacture of soft caviar. The number of beluga has been sharply reduced by the destruction of the conditions for their reproduction by construction of a series of hydroelectrical projects, as well as by the pollution of rivers with industrial waste.
REFERENCESBerg, L. S. Ryby presnykh vod SSSR i sopredel’nykh stran, 4th ed., part 1. Moscow-Leningrad, 1948.
Promyslovye ryby SSSR: Opisanie ryb. Moscow, 1949. [Text and atlas.]