Sanhe Swimming Crab is currently the main object of shrimp pond breeding in our county. However, the traditional culture methods cannot overcome the production problems of the similar parallaxes of swimming crabs, nor can they prevent the crabs from killing the polyculture varieties such as prawns and oysters in the same pool. As a result, the productivity and efficiency of the ponds are low. In 1999, we carried out a 300-mu aquaculture cultivation of three-handed portuguese crabs, with a total output of 48 tons, 160 kilograms per mu, a production value of 11,200 yuan per mu, and a net income of 7,200 yuan per mu. The breeding survival rate was 80%. The following aspects of technical measures. I. Shrimp pool conditions 1. Shrimp pool basic conditions: an area of ​​5 to 10 acres, easy access to water, adequate water, fresh sea water without pollution, salinity between 25 ‰ 35 ä¸ not less than 20 ‰, PH value Between 7.8?8.5%, the water depth is 1.5?2m, and the sediment is sandy or sandy and muddy. 2. Drainage and siltation in shrimp ponds: drain the pool water to dry it, remove excess silt and expose to sunlight. Before 15 days before transplanting, 50-60 kg of quicklime was used to clear the pond and disinfected, and 10 ppm of tea seed cake was further used for clearing the pond 4 to 5 days prior to planting, thoroughly removing fish, fish eggs, etc., and then using 60 mesh. Screening water 60Cm, water, fertilizer and water, and can be appropriate to stock some of the Chinese shrimp seedlings, the density of 2000 to 3000 tail / acre, in order to make full use of the shrimp pond. 2. Hanging and Drifting Method Use 4# cold wire drawing on the shrimp pond parallel to the line, fixed at both ends, supported by wooden stakes in the middle, set up a stake every 8m. Put 1/3 of fine sand in the plastic half float for horizontal use of the shuttle crab and external polyethylene plastic drafting net. The height of the drafting net is appropriate to half drift from the bottom of the pool 0.4m, and the net of the drafting net is appropriate. Use iron wire to circle a round mouth with a diameter of about 15Cm to feed the bait, and then fix one end of the round mouth to the rack wire. The mesh mouth should be at least 30Cm above the surface of the pool water, and stock up to about 4Cm in each float. Crabs float 800 per mu. 3. Cultivation of crab seedlings Cultivation of seedlings of crab species with a size of 1.2Cm/tail from a nursery farm are placed in a small pool for raising, and small feeds such as Dafengnyi, copepods, and surimi are fed. 100% to 200% of body weight, taking a small number of times, feeding 2 to 3 times a day. After 20 to 30 days, it can grow to a shelf width of 3Cm. 4. Aquaculture Management 1. Baits: The same as feeding other fish species, the use of cheap small trash fish, fresh fish is better, commonly used fish, small yellow croaker, etc., supplemented by live mussels, but in the young crab stage and the spring and autumn In the season when the water temperature is low, it is best to mix mixed shrimps and miscellaneous fish. The amount of feeding can be 5% to 10% of the stocking weight, and feeding in the evening. 2. Change the water: The shuttle crab is happy to live in an environment with fresh water and high dissolved oxygen content. Oxygen consumption is large in the clam shell and it is particularly sensitive to water quality. Normally, change the water once every 3 to 4 days. Do not drain the water when changing the water. If the maximum displacement is required, keep the depth of 50 cm in the pool. V. Appropriate Harvest When the crab reaches a commercial size of 0.25 kg/only, it can be harvested. Put the pooled crabs in ice water at about 10°C to make them dull. Then use a rubber band to tie the chelipeds, put them in cardboard boxes, and put sawdust and ice on the market. If the natural seedlings can be acquired sequentially at different times, they can be bred separately and then listed as they grow. This growth is fast and shrimp ponds can be fully utilized.
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