In many countries, for example, in Hungary and Czechoslovakia, catfishes are bred in special fish farm. Young individuals then occupy reservoirs of different function. In Russia such species of fishes is parted for stocking of large reservoirs.
Instruction
1. The catfish is large predatory fish. For example, in Dnieper it is possible to meet copies which length about 5 meters, and weight – 300 kilograms. Usually som weigh from 16 to 55 kilograms. This fish quickly grows. Maturing happens 4-5 summer age.
2. It is possible to grow up catfish in reservoirs and ponds. At the expense of it the ryboproduktivnost increases by 110 kg/hectare. These individuals eat weed fish, frogs, tadpoles, rigid fauna of fish-breeding ponds and also fitofilny organisms of zoobenthos.
3. The producer is usually prepared in natural reservoirs. It becomes approximately in year prior to fish-breeding works. The periods favorable for this purpose – fall and spring. At this moment the som concentrate on holes. It is possible to catch catfish the active tool of fishing. Best of all 5-9 summer individuals are suitable for reproduction. Length their about 1 meter. In winter time of som does not eat therefore it can be held together with other fish in zimovalny pond.
4. It is necessary to separate females from males in the spring. They differ in convex paunch and the rounded head. At males the paunch is tightened, and the head has the angular form. Because sex determination and conditions of sexual products at som is complicated, it is necessary to use the special device which exercises optical control of state. The urethroscope, the cystoscope and otoscope is most often used for such purpose.
5. Before spawning of som actively consumes food. For spawning the fish needs to be placed in small pond which area about 700 sq.m. The bottom surely has to be dense. It is the best of all to apply slots which are made of air root of willow to spawning substrate. Them fix to circle which dimeter about 70 centimeters. This detour is taken from wire. The slot can be attached stakes on height of 35 centimeters from bottom. Average depth of pond has to be not less than 1 meter, and water temperature 20C.