In order to give full play to the breeding advantages of Penaeus vannamei, tap the potential of the pond, extend the breeding period, and achieve a balanced market to further increase the yield and economic efficiency of Penaeus vannamei. Hangzhou Aquatic Technology Promotion Station conducted a high-yield and high-efficiency aquaculture trial of the South American white prawn freshwater dip in the key aquaculture areas in Hangzhou from 2002 to 2003, and achieved a good yield of 518 kilograms per mu and profit of 4,662 yuan per mu. The key points of the high yield and high-efficiency breeding techniques of the South American white prawn oyster are described below. I. Pond conditions Shrimp ponds should have sufficient water sources, good water quality, no pollution, and water quality conforms to the provisions of GB11607. The bottom of the pool is flat, less silt, and easy to enter and drain. Area of ​​3-10 acres, the most suitable area of ​​3-5 acres, water depth of 1.8-2.5 meters. Each pond needs to be equipped with 2-3 aerators. Second, the preparation before release, clear pond disinfection. For new ponds, advanced water soaking, and then drug disinfection; the old ponds or ponds transformed into ponds need to be exposed to dry ponds for 20-25 days, completely remove silt and weeds and then disinfect, then use quicklime 80- 100 kg/mu thoroughly disinfected. 2, to cultivate basic food. 5-7 days before seedling emergence, the microbial composite preparation EM was exposed 1-1.5 kg per mu. Then, 2 days before planting, appropriate amount of urea and superphosphate are applied per mu of pond, so that the transparency of the pool water is 25-30 cm, and the water color is dark brown or yellow-green. 3, adjust the water salinity. For pure freshwater ponds, 1-2 days before planting, 150-200 kilograms of coarse salt or sea crystal should be cast per acre, and the pool water salinity should be adjusted to 1 ‰-1.5 ‰. Third, the choice of shrimp and stocking 1, selection and desalination of shrimp. High-quality shrimp is an important guarantee for improving the survival rate and high yield. Penaeus vannamei seedlings should be selected to be robust and disease-free. Before going into the shrimp, they must be quarantined at the local quality and quarantine department, and they should not enter the seedlings from the affected area to prevent the introduction of the virus. Stocking specifications are better than 1.0 cm. For the first time, the cultured shrimps were kept in a nylon greenhouse (or greenhouse) due to earlier time and lower temperature, and they were diluted for 10-15 days. When desalting, the daily reduced salinity does not exceed 1 Torr until the salinity drops to 1 ‰ - 1.5 ‰. The shrimp size reaches 1.0-1.5 before it is put into the outdoor shrimp pond. Secondly, the cultured shrimp seedlings shall be surrounded by nylon cloth to surround a few square meters of holding tanks or large tanks and put dense net cages to desalinate the rough for 7-8 days, and then put them into the shrimp ponds. Farming. 2, shrimp stocking. Stocking time: The first choice is in mid-May, the water temperature is stable above 20°C, and the stocking density should be 3.8-40,000/mu. The second stocking density is 2.8-3.0 million mu per acre, which should not be too high, otherwise it will affect the growth and out-of-pool specifications of the second mussel. Fourth, feeding and management 1, water quality management. The quality of water directly affects the growth and survival rate of shrimp. In the early stage of cultivation, water is mainly added; in the middle and later stages, more water and water are replaced, and the water is changed every 5-7 days, but the amount of water exchanged does not exceed 30%. At the same time, in accordance with changes in climate and water quality in a timely manner to open the aerator, apply photosynthetic bacteria or EM original dew every 15-20 days to improve the bottom quality and purify water quality. 2, feed feeding. Feed selection Whitebait is a full-priced pellet feed. First of all, ensure that the quality of fresh feed is not deteriorating, and the particle size is suitable; secondly, control and adjustment of the amount of feed. The daily feed is 3% to 5% of the shrimp's body weight. However, in actual aquaculture production, it is determined by the shrimp's feeding condition, water quality, and temperature. Fifth, disease prevention adheres to the principle of “prevention and health managementâ€. Every 15 to 20 days, alternately disinfecting with environmental drugs such as quicklime, dibromohydantoin, photosynthetic bacteria, and EM. If artificially fed feeds are fed, then 1‰-2‰ of vitamin C, immune polysaccharides, etc. are regularly added to enhance the immunity of shrimp. When the water is changed, it is not a big irrigation and the water quality is relatively stable. 6. The method of harvesting the marketed white prawns of South America is mainly trapped in the ground cage nets, and finally caught in dry ponds. The harvest time is determined according to market demand, price and growth situation. When the South American white prawn is bred for 70-80 days, the specifications can reach 60-90 tails/kilogram, then the catch will remain small, the batch will be harvested and marketed, and the last dry catch Finish. The first shrimp will be fought in late July and early August so as not to affect the stocking and growth of the second prawns too late.
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