1 Pros and cons of crab and shrimp polyculture 1.1 Crabs and shrimps are all crustaceans, and the inhabiting water layer is basically the same. There is a space for the two sides to compete for space. However, due to their small size, the young shrimps can live in a narrow space where crabs cannot inhabit. It also has no impact on habitability of crabs and can make full use of the remaining space that cannot be used by crabs to ensure that the water is not wasted. 1.2 Crabs and shrimps are basically omnivorous. The two polycultures may compete for food, but crabs are biased toward animal feeding and eating habits. Shrimp is biased towards plant food and can use food scraps and baits that cannot be used by crabs. , purify water quality. 1.3 Crabs and shrimps need fresh water, rich oxygen-rich environment, crab pool mixed with green shrimp, because of the higher oxygen tolerance of crabs than shrimp, when the water body is deprived of oxygen, shrimp first showed an unpleasant reaction, can play The role of the "warning" can remind people to take measures as soon as possible, add new water, and ensure that the crab breeding will not suffer losses. 1.4 The shrimp has strong fertility and fast growth. In the crab pool, when animal feed is lacking, some of the shrimp can be eaten directly by the crab, increasing the animal food of the crab and providing nutrition for the crab. The shrimp that have not been eaten by the crabs grow bigger and are welcomed by the market. The higher prices can improve the overall economic benefits. 2 Method of polyculture of crabs and shrimps. Crab ponds are mixed with fresh shrimps. The crabs can be stocked in accordance with conventional methods. Green shrimp can be put before or after crabs are released. The source of shrimp species should be adapted to local conditions and be flexible. It can be used to raise egg-holding shrimps as well as juvenile shrimps. However, young shrimps should be placed in small water bodies before they are intensively cultivated and then released to increase the survival rate. Smaller ponds can be stocked in the spring for catching egg-holding shrimps from rivers and other wild water bodies. When catching fish or fish species and ponds, the captured prawn can be put directly into a crab pond for natural breeding. . Under normal circumstances, every 667m2 can hold 3 to 5kg of the shrimp (1.0 to 1.5kg or 3cm) and 20,000 to 40,000 shrimp (1cm or more). The stocking should be put in place so that the shrimp can be distributed as early as possible in the water body. Placement can be in the shallow water near the pool or where there are more aquatic plants. Early-range freshwater prawn, after 2 to 3 months of breeding, part of the product can grow into specifications, then you can catch large and small, loose density, to ensure that the smallest shrimp can also reach the end of the product specifications. Stocking eggs can be hatched in small cages, and broodstock can be caught on the market immediately after spawning. Where conditions permit, it is also possible to add some shrimp species after the capture of prawn and implement round catching, which can significantly increase economic efficiency and make full use of water resources. 3 Breeding management matters 3.1 After the shrimps are stocked, the water space of the crab pool is basically used, and water quality management should be strengthened. First, we must plant more plants to allow the green shrimp and crabs to inhabit and live in the water plants without disturbing each other, which is conducive to their own growth. Insufficient water and grass in the pool can be temporarily collected in the river ditch. Second, shallow banks should be set up in different areas along the pool and in the water to increase the area for shallow water activities and increase the breeding space. Third, it is necessary to change new water frequently to maintain good water quality. Mixed-breeding ponds require more fresh water than ponds that only use crabs. In spring and autumn, they change their waters from 5 to 10 days, and in the summer 2 to 3 days, they change their waters once a day, during the hot summer season and in hot weather. In the evening, you should stick to the morning and evening patrol, find problems, and solve them immediately. If a large number of shrimps are found in the poolside, with jumps, it is a sign of lack of oxygen in the pool. You should immediately change the pool water, or you can use an oxygenating agent for artificial first aid. Then analyze the causes and take measures to prevent shortages. Oxygen pan. 3.2 Feeding on Feed Under the premise of ensuring the food intake of crabs, consciously increasing the amount of food that the shrimps prefer to eat can feed powders and fine-grained foods with high protein content. Under normal circumstances, the total feeding amount in the pool can be slightly higher than that of the single crab to meet the needs of the shrimp, which is beneficial to the growth of crabs and shrimps. However, in the specific feeding, we should adhere to the principle of rather less and more, in order to maximize the use of natural food in the crab pool, otherwise it will waste food, water quality. 3.3 Shrimp are generally less likely to get sick. Under the precondition of good prevention of crab disease, it is not necessary to take any precautionary measures against the shrimp. However, the drugs for preventing crab disease should be particularly careful, and the sensitive drugs against the shrimp should be killed. , Trichlorfon, etc. Try not to use it. In peacetime, regular use of quicklime (every 667m2 dosage 10 ~ 15kg) of Quanhua Quanchiposa, shrimp and crab are beneficial. 4 The arrest and sale of polyculture of crabs in crab ponds should adopt the method of catching and catching fresh shrimps, insisting on catching large and small animals, and adopting the principle of multiple captures. Because the growth rate of the shrimp is different and the specifications are different, this will increase the proportion of large-sized shrimps to market and increase the quality. Should not be caught once after the dry pool. Otherwise, shrimp and sediment are mixed together, one impact capture, and the second is difficult to catch clean. The catch can be caught with shrimp cages, nets, etc., and can also be caught in water grasses using a dip net. The captured shrimp should be sized and distributed and sold according to specifications. At the end of the year, freshly caught shrimp can be kept in the cage for a day and night to wash dirt inside and outside the house, which can improve the quality of sales.
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