pisciculture), a sector of the national economy concerned with breeding fish to increase and improve fish stocks. It includes the raising of fish in natural bodies of water and in artificial ponds. Fish culture in natural waters is concerned with the replenishment and improvement of the fish stocks of rivers, lakes, reservoirs, and seas. The increasing impact of man on such waters (water pollution and construction) has impeded or disrupted the natural replenishment of fish stocks. Thus, the rearing of fish, that is, fish-farming, is needed to maintain the existing fish life and to improve an ichthyofauna of minor value. Semimigratory (pike-perch, carp, roach) and migratory fishes (sturgeon, beluga, stellate sturgeon, inconnu, Atlantic salmon, chum salmon, pink salmon, Baltic vimba, and kutum) are particularly threatened. Semimigratory fishes inhabit lakes, rivers, and the mouths of rivers; and migratory fishes inhabit seas but travel, often hundreds of kilometers, up rivers for reproduction. However, as a result of construction on the rivers, the spawning grounds are cut off by dams from the feeding areas, and timber floating on the rivers leads to the destruction of the spawning grounds. The founder of fish culture in natural waters in Russia was V. P. Vrasskii, who developed the “Russian” method of artificial impregnation and incubation. In 1857 he built the first hatchery for rearing salmon and whitefish. It was situated on the Pestovka River in the village of Nikol’skoe, Novgorod Province. Similar hatcheries were subsequently built on various rivers for raising Atlantic salmon, Baltic salmon, and sturgeon. However, until the October Revolution of 1917 fish culture in natural waters was carried out by volunteer societies and amateurs. In the USSR the raising of fish in natural waters has developed significantly. Since 1934 fish raising, reclamative projects, and the regulation of fishing in natural waters have been administered by the Central Board for the Conservation and Replenishment of Fish Stocks and for the Regulation of Fishing of the Ministry of Fisheries of the USSR. Fish culture is carried out together with land reclamation and the acclimatization of valuable fish species that use feed resources more productively than the indigenous fish life. Such reclamative projects as water purification, control of silting and vegetation overgrowth, construction of fish passes and fish lifts in the dams of hydraulic engineering installations, and the equipping of intake structures with fish-protection devices have restored and improved natural conditions for the breeding and feeding of the fish and have created a constant water system in the spawning grounds. Passage of fish to spawning grounds is ensured by cleaning and deepening the channels and by eliminating obstructions on rivers. If natural spawning grounds are scarce, artificial ones (permanent and floating) are built. Fish-farming makes it possible to replace partially or completely natural breeding and to populate the natural waters with acclimatized species of fish. Fish hatcheries engaged in incubating roe and rearing fry for subsequent release into natural waters have been constructed on rivers and in the basins of many seas. To replenish the stocks of such semimigratory fish as pike-perch, bream, and carp, the network of spawning and rearing farms is being expanded. Important work is being done by acclimatization stations, which supply stock to various bodies of water as many as 300 times a year. In 1968, for the first time in world practice, a general plan was worked out for the acclimatization of fish and other aquatic organisms in Soviet waters for the period 1970–80. The plan is being successfully carried out: for example, the Far Eastern pink salmon has been acclimatized in the basin of the Barents Sea, and the Siberian whitefish, or peled, has been introduced in many bodies of water. Pond fish culture involves the breeding and raising of fish in specially constructed ponds. This form of fish rearing involves control by man of the entire production process—from breeding to the obtaining of a marketable product. In Russia raising fish in ponds existed in the 12th and 13th centuries (chiefly at monasteries). Until the end of the 14th century, such farms raised fish (sterlet, pike-perch, pike, and tench) caught in lakes and rivers. A. T. Bolotov was the first to build special ponds for rearing carp. In the USSR there are special research institutes concerned with such problems as feeding the fish, fertilizing the ponds, raising fish to a marketable weight at an accelerated pace, rearing fish in rice paddies, and raising ducks on fish ponds (seeFISH-AND-DUCK FARM).
Posted on: Tue, 15 Oct 2013 00:56:57 +0000
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