Pond Fishery

a farm that raises rapidly growing fish species in specially constructed or adapted ponds. There are warm-water and cold-water pond fisheries.

Warm-water pond fisheries primarily raise domesticated carp, as well as such other warm-water fishes as the grasscarp, bighead carp, silver carp, crucian carp, pike, sterlet, and pike perch. There are three types of carp farms: full-system farms (fish-breeding plants), partial-system farms (fish nurseries), and one-year fattening farms. The production cycle on a full-system carp farm is as follows: In the spring the necessary number of breeding carp are placed in the spawning ponds. Six or seven days after they emerge from the eggs, the young are counted and placed in each of the nursery ponds, where they remain until autumn. Before the onset of night frosts, the water is drained and the young carp are sorted and placed in winter ponds. In the spring the one-year-old carp are transferred from their winter ponds to fattening ponds, where they reach market weight by autumn.

Pond fisheries operate on different cycles, since the period of time needed to raise a fish from spawn to market weight varies from region to region. Carp farms in the USSR are mostly on a two-year cycle (the fish are raised for 16 or 17 months). In the northern regions there is a three-year cycle (28 or 29 months), and in the southern regions a two- or one-year cycle (five or six months). In the central zone of the European USSR the standard weight for a one-year-old carp is 25–30 g; the standard weight for a two-year-old is 500 g. Fish nurseries raise only carp under one year of age, keeping the fish only until the end of winter. The carp are then used to stock other pond fisheries. On one-year fattening farms, food fish are raised from one-year-olds obtained at nurseries and full-system fish-breeding plants.

Some pond fisheries raise the fish on whatever natural food the ponds provide; their output can be increased only by increasing the area of the ponds. More practical and economical are pond fisheries that improve and fertilize the ponds and give the carp special feed mixtures; output is increased many times over at such fisheries. In order to make better use of natural food supplies and to boost production, tench, goldfish, peled, cisco, Ladoga lake cisco, and other fish are placed in fattening ponds along with the carp. The advanced pond fisheries in the USSR, which implement measures to intensify fish breeding, produce more than 20 quintals (up to 70 quintals) of fish per hectare of pond.

Because of biological features distinct to carp, ponds for these fish are shallow and are kept quite warm. The bottom is silty, and the vegetation is moderately developed. Rice paddies that have been flooded with water are also used in carp breeding. Carp are sometimes raised on fish-and-duck farms, where the ponds are used to raise both fish and ducks.

Cold-water pond fisheries raise cold-water fishes, mainly rainbow and brook trout. Trout require spring-fed ponds with a rocky, sandy bottom and a swift current. Trout farms are established along mountain rivers or cold springs; in specially constructed trout ponds the bottom and banks are concreted. Because trout will not reproduce in ponds, the eggs are artificially fertilized and incubated at hatcheries. At one year of age the young are placed in fattening ponds, where they attain a market weight of 150–200 g or greater. Like carp farms, trout farms are divided into full-system farms, partial-system farms, and fattening farms.

The pond fisheries in the USSR include approximately 9,000 carp farms, approximately 50 trout farms, and more than 280 specialized commercial fish-breeding plants of the Ministry of Fisheries of the USSR. The total pond area is approximately 124,000 hectares. In 1973 approximately 1.3 million quintals of fish were produced at pond fisheries.

Outside the USSR, the most developed pond fisheries are in Japan, Denmark, Norway, Israel, the Federal Republic of Germany, Hungary, Yugoslavia, and the German Democratic Republic. The main species raised at the pond fisheries in these countries is carp, although significant numbers of trout are also produced, especially in Denmark and Japan. In the United States mostly catfish and trout are raised in ponds. In 1972 the production of pond fish totaled 120,000 tons in the United States, 100,000–120,000 tons in Japan, approximately 14,000 tons in Israel, 24,000 tons in Hungary, 18,300 tons in Yugoslavia, 12,000 tons in Poland, and 10,000 tons in the German Democratic Republic.