a form of carp reared in ponds. The domesticated carp breeds differ in scaly covering: there are scaly, mirror, and leather carp. The Ukrainian mirror and Ukrainian scaly carp are bred in the USSR. The carp is thermophilic (it tolerates a temperature of up to 35°C) and hardy, lives in ponds with little oxygen, and tolerates considerable pollution. It reaches sexual maturity in three-five years. It spawns in spring on freshly flooded vegetation and produces 700, 000–, 000 eggs. The fry feed at first on zooplankton and then on zoobenthos (mainly chironomid larvae). Toward fall the fish begin to feed on vegetation.
Domesticated carp is the main fish raised in warm-water pond fish farms in most countries. Its growth rate is greatest when the water temperature ranges from 20° to 28°C and the oxygen content of the water is 5– mg per liter in summer and no less than 4 mg per liter in winter. When the water temperature drops below 14°C, the carp consumes much less food, and at 1°-2°C it becomes torpid, ceases to feed, and loses weight. Insufficient food and poor maintenance result in degeneration. The fish productivity of the ponds is increased by concentrated stocking and feeding (introduction of feed into a pond in addition to natural carp food). When a pond is stocked normally in terms of solely the natural food already present, the carp usually are not fed. When the stocking is done at twofold, threefold, fourfold, or fivefold concentrations, special feed mixtures are added in the form of a doughy mass or granules. The mixtures include oil cakes, groats, seeds of legumes (lupine, vetch, peas, lentils, soybeans, beans), grain, flour, and grain bran (from corn, rye, barley, and sorghum), horse chestnuts, malt sprouts, brewers’ grains, and feed of animal origin (fish, meat, blood meal, slaughterhouse and meat-packing wastes). In specialized state carp fish farms, the fish are fed mixed feed of industrial origin. Feeding domestic carp increases the fish yield per hectare of pond area by five to six times or more.
In the USSR, domestic carp is raised in the RSFSR, Ukraine, Byelorussia, and elsewhere. Fish-breeding ponds and a great variety of bodies of water, including rice paddies, are used for this purpose. The following breeds are raised: scaly, mirror (with scales scattered over the body), linear (with scales arranged along the lateral line), leather (without scales), Ukrainian mirror, and Ukrainian scaly carp. In the pond fish farms of the European USSR, fingerlings weigh 25– g, commercial two-year-olds weigh 500– g, and three-year-olds weigh 1, 200–, 000 g. In 1971, the state fish farms of the USSR and fish farms of kolkhozes and sovkhozes produced 646, 700 and 160, 000 centners of domesticated carp, respectively. Efforts are under way to develop breeds that withstand cold and to introduce them into the northern regions of the country.
REFERENCEMartyshev, F. G. Kratkii kurs prudovogo rybovodstva. Moscow, 1964.
A. A. SVETOVIDOVA and A. S. VAVILKIN