Cultivation of parent Fish of Autumn Grass

The sex cells of grass carp are in the period of growth and development in autumn and winter. the quality of feeding and management at this stage directly affects the gonadal maturation, the effect of spawning in the second year, and the fertilization rate and hatching rate of fish eggs. For this reason, the cultivation of grass carp should be grasped from the following points in autumn and winter. 1. Prepare the fish pond. To cultivate grass parent fish ponds, it is required to be close to the spawning pond and have good water sources. The area of the fish pond is generally 340 mu and the water depth is 1.5 meters. Before the parent fish is released, the fish pond should be cleaned, the ridge of the pond should be maintained, the weeds should be removed, and the fish pond should be disinfected with drugs such as quicklime or bleach powder. 2. Parent fish are released. The release time of parent fish is generally between 10 and 12 months. Parent fish used for breeding are best bred locally, and can also be fished from rivers, lakes and reservoirs. Fishing is carried out from November to December, because the water temperature is low, the fishing and transportation of parent fish are not easy to be injured, the survival rate is high, and it is not easy to die after stocking. Early fishing can restore the physique of parent fish for a period of time, develop normally after the beginning of spring and catch up with reproduction. Stocking density is very important. In ponds dominated by grass carp, 130-150 kg of grass carp are released per mu, that is, 12-15 grass carp weighing 7-10 kg per mu. In addition, 3 silver carp and bighead carp were raised. 3. Feeding and management. ① scientific feeding. In the early stage, green feed should be given priority to, and green feed should be combined with concentrate. Green materials can be used with grass, ryegrass, red vetch, etc., depending on the feeding of parent fish. The green feed can be up to 30% of the fish's body weight and the concentrate is 1 / 2% of the fish's body weight. With the decrease of temperature, the green feed is gradually exhausted, and the food intake of grass parent fish is decreasing day by day, so all concentrate should be used at this time. The feeding method should be mastered: if the water temperature is high, it can be fed every other day; when the water temperature is low, it can be fed once every 3 days. Concentrate should be put on the table, which should be set up at the bottom near the shore; the green material should be put into the basket, and the grass basket should be moved regularly to remove the sunken rotten grass. ② keeps the water quality fresh and injects fresh water regularly, usually once every 15 to 30 days. ③ prevents and treats diseases. Grass carp in autumn and winter season is easy to suffer from enteritis, water mold, rotten gills and other diseases, once found that fish disease should be diagnosed in time, symptomatic treatment. Appropriate amount of quicklime and bleach solution can be sprinkled into the pond every month to prevent the disease.