Fishpond(redirected from Fishponds)
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a body of water constructed or adapted specifically for raising fish. At pond fisheries, meadows or marshy areas are allocated for ponds for warm-water fishes (carp, crucian carp, tench, bream). The water is supplied by small rivers and lakes, artesian wells, the waters from state regional power plants, and other sources. Ponds for raising cold-water fishes (trout, salmon, whitefish) are established in areas where the soils are not rich in organic matter; the water, which is from a stream or cold river, is cold, clean, and oxygen-rich. Springs contaminated with sewage and swamp water rich in iron oxide and having an acidic reaction are not suitable water sources for fishponds.
There are special devices for completely draining the pond and refilling it at the proper time. Nondraining ponds, in which the bottom is free of stumps, submerged shrubbery, and other objects that hinder the removal of all the fish from the pond, can also be used. The outflow and inflow systems are equipped with screens to prevent wild fish from entering the pond and the fish inside from escaping.
Fishponds are most often established on the floodplains of small rivers. The floodplains are partitioned off by an earthen dam with a sluice for draining the pond and a spillway for discharging water from floods and heavy rains. Such ponds are called riverbed ponds and are the least expensive to construct. However, they do have disadvantages: it is impossible to completely drain the water (since the riverbed is located within the pond), and it is difficult to keep out wild fish.
Fattening ponds, in which the fish are raised (fattened) to market weight, are most frequently made in river beds. They are the largest type of fishpond, with areas of several hundred hectares (ha) and depths of 0.5–2 m. Spawning, nursery, and winter ponds are usually established on a flood-plain by enclosing a section with earthen dikes. To supply water to such a pond, a head pond is constructed higher up the river with the aid of a dam; the water is fed to the fishpond by a special canal. Water outlets are installed in the ponds.
Spawning ponds, which are established at warm-water pond fisheries, have an area of 0.1–0.3 ha and an average depth of 0.6–0.8 m (in spawning sections, 15–30 cm). They are inundated with water only during spawning and larval development (two or three weeks). Nursery ponds are used for raising young fish under one year of age to standard weight and fatness. Their area is 10–15 ha, and their average depth 0.5–0.8 m. Winter ponds hold the young fish throughout the winter. They are usually 0.5–1 ha (to 1.5 ha) in area, and the depth of the nonfreezing layer of water is 0.8–1.3 m.
Care of fishponds entails proper maintenance of the hydro-engineering structures, removal of surface vegetation (reeds, rushes, cattails), and prevention of contamination by sewage and silt. Once every four to six years, fattening ponds are left without water.
REFERENCEMartyshev, F. G. Prudovoe rybovodstvo. Moscow, 1973.
F. G. MARTYSHEV