Early winter and early spring are the critical period for broodstock breeding. Some farmers have visited the rounds of listing and ignoring the cultivation of broodstock, laying hidden dangers for fishery production in spring and summer. Therefore, in order to have a good fish culture, the winter and spring foundations must be laid.
First, the selection of healthy and disease-free varieties of mixed diseased fish species, often give pond fish buried the shadow of the source of disease, therefore, the choice of fish species should be careful, pay attention to identify the male and female and maintain the male to female ratio of 1:1 to 1.5. General male fish mature earlier than female fish, too many males, will occupy the pond, consume feed, increase costs. The main purpose of broodstock rearing is to promote gonad development, generally adopt polyculture, and the stocking density is based on comprehensive consideration of the type of main fish, water quality, feed, and fertilizer. The main carp can be stocked with 100-140 kg per mu; the main carp can be stocked with 80-100 kg per mu. In grass- and bluefish-based ponds, usually 120-140 kg of grass carp or herring are released per acre.
Second, timely fertilization prompts the broodstock to save sufficient nutrition In order to ensure the normal development of the broodstock ovaries in spring, the timely observation of water fertilization in winter is the key. Aphids and centipedes feed on plankton, usually about 400 kilograms of manure per acre per half a month, making the water thicker. At the same time, a small amount of supplementary fertilization should be applied after winter, and fertilization should follow the principle of “a small amount of time and continuous supplementâ€. . Fertilizer also applied fertilizer, the best use of compost water.
Third, the rational feeding of feed to cultivate good grass, blue and other eating broodstock is the key to feed properly feed. In winter, the water temperature gradually decreases, and the feeding intensity of grass carp gradually decreases. The source of green material is also gradually deficient. After the temperature is warmer, the feeding should be based on concentrated material. Generally, the broodstock needs 10~15 kilograms of body weight per side, and 50 grams of concentrate is fed on a daily basis. about. Feeding according to the "four definite" feeding method, fine, green material should be placed in time, usually in the morning put green material, accounting for 30% to 50% of broodstock weight, afternoon investment concentrates accounted for 2% to 3% of broodstock weight. In colder winter weather, concentrate feeding should be appropriately reduced. Normally, it should be put in every other day when the water temperature is high, and once in 3 days when the water temperature is low. Herring is mainly fed with snails, clams and quail meats, supplemented with small amounts of bean cakes and other concentrates.
Fourth, early spring appropriate adjustment of water quality Early spring regular water injection, adjust water quality, is conducive to broodstock gonadal development and maturation. The new water should be added according to the season, water quality, and broodstock feeding conditions. Generally, every 10 to 15 days, flush water once, each time to make the water level rise 10~17 cm is appropriate. When the deterioration of pool water is severe, water change measures should be adopted. The broodstock breeding pond should be equipped with a special aerator, which can normally be turned on for oxygen at 2 to 3 o'clock noon on a sunny day. When the floating head is dangerous, the oxygen can be turned on to ensure the safety of the broodstock.
Fifth, regular disinfection and disease prevention, to prevent the occurrence of disease generally every 15 days on the ponds, food tables and other bleaching powder disinfection 1, regular cleaning and drying food table. Water-blocking fashion is good for blocking facilities to prevent predators from entering the pro-fish pond. Strengthen day-to-day management, make it possible to cultivate broodstock, full-time staff management, special feeds, and touring ponds in the morning and in the evening to increase oxygen levels. When a disease occurs, professional technicians should be promptly asked to correctly diagnose the disease.
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