Ecological Culture techniques of Chinese Mitten Crab Eriocheir sinensis

Chinese mitten crab, also known as river crab, is a famous aquatic product in our county with delicious taste and high nutritional value. it is not only a favorite high-grade aquatic product for consumers, but also one of the main freshwater aquaculture varieties for export. Along the Langchuan River Basin, our county is rich in ponds, lakes, beaches and reservoirs, luxuriant aquatic plants, fresh water quality, rich species of Corbicula and benthos, which is suitable for the development of river crab culture. At present, our county has cultivated more than 50, 000 mu of river crabs, with an annual output of more than 2000 tons, accounting for 1/10 of the total output of aquatic products in the county. The technology is designed to achieve a yield of 50-60 kg per mu of river crabs, with an average specification of more than 3 taels and a recapture rate of more than 70%. 1. Pond conditions: newly opened ponds (excavated by bulldozers) are the best, and general ponds can also be used. Specific requirements: the area is 10-30 mu, the minimum is not less than 5 mu, the maximum is not more than 50 mu, the water depth is 1.2-2m, the average is about 1.5m; the slope ratio is 1:3-4, ensuring a certain shallow beach area (gentle slope crabs are not easy to drill holes); the silt is less than 10cm, preferably about 5cm; the pond corner is arc-shaped The center of the pool is a shallow area (flat bottom), the highest water level is 0.5-0.8 meters, and the front and rear of the bank foot around the pool is a deep water area, with a width of 5-8 meters, and the highest water level can reach 1.5-2 meters; the inlet and outlet is arranged on the diagonal of the pond to facilitate the formation of circulating water during water injection; it is convenient to enter and discharge, and the water quality of the outer river is good. According to the specific situation, it can be matched with water storage and disinfection purification pool (planting water plants and appropriate amount of water hyacinth), and the water capacity of crab pond is 20 cm at a time. Second, cleaning pond disinfection, generally required to be completed before the Spring Festival. First of all, remove too much silt (the old crab pond had better use a bulldozer to transform the good quality), and then expose to the sun for 15-30 days to promote the decomposition of organic matter in the sediment. Then irrigate 20 centimeters of water, sprinkle it with 150-200 kg / mu of quicklime in the whole pool, and then evenly rake the bottom mud; you can also use tea meal to remove the wild, soak the tea meal for 24 hours before use, add 1% salt water, the effect is better, the sprinkling concentration is 20-30 g / m3. 3. Prepare before planting 1. The inside of the ridge of the escape prevention facility is surrounded by thickened film, calcium plastic plate and aluminum skin. It is 10-15 cm in mud, 50 cm above the surface, and a support pile is set every 0.5-1 m. It is best to set up a mesh around the periphery, with a height of 2 m. 2. Filter facility 60 mesh double screen filter inlet and drainage. 3. In the temporary culture area, 10 days before the crab is planted in the pond, the net circle pond area 1x10-1stroke 5 is used as the temporary culture area, which is located in the deep water area or in the crab ditch (where the water level is relatively deep). When the coverage rate of aquatic plants reaches 50%-60%, the net in the temporary culture area is removed. The temporary culture time is generally up to April, and no later than the end of May at the latest, so as not to affect the growth of river crabs. 4. Crab species should be selected and purchased locally. The specifications are basically uniform, feet and claws are intact (including no wear and tear of claw tips), bright and clean color, fresh and no attachment, translucent long-legged Yangtze River crab species, 100-200 crabs / kg. 5. the pre-stocking treatment was first soaked in the pool for 2 minutes and then put forward for a moment, then soaked for 2 minutes and then repeated for 3 times. After soaking in 10-20 mg / L potassium permanganate for about 30 minutes, or 3-4% saline solution for 3-5 minutes, and then rearing in Tangkou temporary culture area, the water level of crab breeding was controlled at 50-60 cm (spring).