The country's crab breeding area, Chongming County, Shanghai, has fully utilized the resources of crab seedlings to carry out the intensive culture of fish and ponds. The crabs have been preserved for more than 10 years. Under the premise of securing 500 kilograms of fish per mu, the rough-cultured crabs are harvested in acres. The production reaches about 15 kilograms. At present, the aquaculture area of ​​the county has reached more than 35,000 mu. Now the technology is described as follows: First, fish pond conditions: The area of ​​intensive fish ponds is as small as a few to as large as tens of mu. As long as the depth of water is between 1 meter and 2.5 meters, the pool pond is neat and wide, with no leakage. After the stocking of crabs is relatively large, we can dig 15 cm wide and 30 cm deep on the pond and spread plastic film to reduce crab escape. Disinfect with clear lime or bleaching pond before stocking. Second, fish, crab stocking: Since crabs prefer to live in clean water, stocking fish should be dominated by grass and alfalfa, accounting for more than 65%, and cockroaches and cockroaches should not exceed 20%. For example, crabs should not be stocked. The average stocking rate per acre is 100 kg to 150 kg. It is better to end the stocking before the end of January. Juvenile crab stocking should not be too large, generally about 5 to 10 grams of juvenile crabs per acre stocking about 300. Juvenile crabs require the same size, completeness and quick response. Place the juvenile crab in the shallow pond of the pond and allow it to climb into the water. After the crab enters the pool, it will mostly play in the pool. The larger the fish pond area is, the lower the crab escape rate is, and the time for the crabs to be stocked is no later than the end of June. Third, management: 1. Feeding: According to conventional techniques of fish farming, there is no need to increase the amount of bait or change the type of bait. 2. Water quality regulation: From April onwards, water is injected once a week. During the high temperature season, water injection is conducted every 2 days and 3 days. Each injection of water is best beside the side row, so that the pool water is micro-flowing. The transparency of the pool water should be maintained at more than 30 cm. 3, Prevention of floating head flooding pond: Crabs are not tolerant to hypoxia. When the local water is deprived of oxygen, the crab first reacts and can easily cause death. Therefore, observation must be strengthened. Every morning and evening, each patrol pond is once. Once it is found that there is shrimp crawling to the shore, it should immediately flush with fresh water or start aerator. 4. Prevention and control of fish diseases: The rational use of drugs to prevent fish diseases and avoid the death of crab poisoning is the key to aquaculture technology. Crabs are very sensitive to organophosphorus pesticides such as trichlorfon, methamidophos, and enemy killers, and have a much lower lethal concentration than fish. If the standard dose of fish disease prevention and control, can easily cause crab death. Lime, bleach, copper sulphate and various oral fish medicines, if used at standard doses, generally do not affect crabs. If you need to use organic phosphorus drugs, especially crystal trichlorfon, you can take hanging bags or food sprinkling. Kn95 5 Layers Mask,Kn95 Filters Face Mask,Kn95 5 Layers Cup Facemask,Kn95 5 Layers Fold Flat Facemask Jiangmen anjian biotechnology co. LTD , https://www.jmanjianmask.com