Preparation of Water Sources and Ponds Conditions Water sources with wide water surface, sufficient water quantity, fresh water, no pollution source, convenient drainage and irrigation, matching power, and convenient transportation. The pond area is preferably 30 square meters 667 square meters to 50 square meters 667 square meters, the pool shape is rectangular, east-west direction, length to width ratio is 4:1, long sunshine hours, large wind area, convenient operation and management; gentle slope The slope ratio is 1:3. Clay soil is preferred for clay. There is a "crab island" in the pool, which accounts for 30% of the area of ​​the pond. It is a quiet place where crabs can be found and eaten. The aquaculture pond is equipped with a microporous aeration facility with a power of 0.15 kW/667 square meters. Anti-escape facilities crabs climb very quickly and have a strong ability to escape. Therefore, anti-escape facilities should be built around crab ponds. The use of calcium-resistant plastic plates with strong anti-oxidation ability is laid along the inside of the pool bowl. The calcium plastic plate is 60 cm to 70 cm high, buried in the soil 10 cm to 20 cm and compacted, and is 50 cm to 60 cm above the ground. The joints between the plates shall be tightly closed, leaving no gaps. After the plates are punched, they shall be tightened with thin iron wire and slightly tilted into the pool. The corners shall be rounded. This kind of anti-escape facilities can resist large-scale storm attacks, and is currently a kind of anti-escape facilities widely used by crab farmers. In addition, on the outside of the pond, 1.2 meters to 1.5 meters high, 10 centimeters in the bottom of the buried soil, surrounded by polyethylene nets fixed with wooden piles or bamboo piles to prevent frogs, ducks and other predators from jumping into Inside the pool. Clear ponds disinfected winter dry ponds to remove weeds from the ponds and silt at the bottom of the pond to reinforce the ponds. After exposure for 15 days to 20 days, the whole pool is splashed with 150 kg/66 m2 to 200 kg/66 m2 of quicklime and water to prepare a solution. Lime clear pond can not only kill harmful organisms and various pathogens in the water, but also improve the bottom soil and increase the calcium content in the water and promote the growth and development of crabs. Prepare for stocking 1. Planting aquatic plants: Planting aquatic plants is an important part of the crab breeding process and an indispensable technical measure. In the crab breeding pond, compounded aquatic plants were planted. Elodea was planted on shallow slopes. Black algae and Vallisneria were planted in deep water, and some emergent plants, such as reeds and alfalfa, were planted on the beach. The water grass coverage rate was over 60%. 2. Water injection and fertilization: fertilizing and cultivating bait organisms after planting and planting, generally applying 50 kg/667 m2 of compound fertilizer and 50 kg/667 m2 of ammonium bicarbonate; the best organic manure with farmyard fertilizer is 1,000 kg. / 667 square meters, once full (farmer fertilizer effect is slow, long-term fertilizer, no effect on the growth of the crab). 3. Release snails: The snails are cheap and have a wide range of sources. Live snail meat is delicious and is a natural feed for crabs. Putting snails in the crab culture ponds at the appropriate time to allow them to reproduce naturally will help reduce costs, increase production, and improve quality, so as to achieve the goal of ecologically efficient farming. Before and after Ching Ming Festival, put snails 200 kg/667 sq.m. to 250 kg/667 sq.m., let them grow and breed naturally, and provide animal feed for eating crabs. In August, it will make up one more investment, and the amount will be 100 kg/667 square meters. Serve 1. Quality of Crabs: Quality requirements for crabs are as follows: neat specifications, bright body surface, robust physique, complete appendages, quick crawling, no injuries, no disease, and no attachments. 2. Sterilization of crabs: Before stocking, the crabs were immersed in 3% to 4% saline (without iodine). 3. Specification, density, time: stocking size is 50/kg~100/kg; stocking density is controlled at 500~600/667 square meters; stocking time is generally controlled at the end of February or early March, and can also be selected before One-year winter stocking. 4. Restocking methods: In aquaculture ponds, the pre-designated breeding area is one-fifth of that of Datang, and the crab species will be placed in the intensive cultivation. When the ponds in Datang grow to account for 50% of the entire pond surface, The snail has been bred for a certain amount and put into the pond for feeding. When the crabs are stocked, the water level is controlled at 50 cm. When the weather is warm and sunny, and the water temperature is high, stocking is required. With the water operation, the operation is brisk, so as to ensure the survival rate. Feeding of dietary feed on river crabs is omnivorous. Commonly used plant feeds include aquatic grasses, wheat, corn, soybean cakes, bran, etc.; animal feeds include snails, clams, cockroaches, fish, and shrimps; and in addition to natural and artificial baits, There is full price with food. The feed should be scientific and reasonable. In the breeding process, scientific feeding should be carried out according to the nutrition and the requirements for the bait size at different stages of the crabs, and the main ingredients should be fed. Daily feeding amount is controlled at 2%~5%. From mid-March to mid-June, feeding time gradually transitioned from 7 o'clock in the morning to 6 o'clock in the morning. In the morning, the amount of bait was controlled at 30% of the whole day and 70% at night. From March to April, river crabs live in the breeding area. The range of feeding water and grasshoppers and snails is small and their amount is small. The amount of feeding should be sufficient. From May to June, aquatic plants basically covered the entire surface of ponds, and snails have also been propagated to a certain number. The crabs can be put into ponds for breeding, and the feeding of ingredients is appropriately controlled. From July to August, the high temperature season will increase some animal food for crabs. The specific amount of feeding is preferably within 1 hour to 2 hours after feeding. Water Quality Management Crabs have high quality requirements for the water environment. Fresh water quality is conducive to the growth and shelling of crabs, and it also increases the taste of crabs. If the pond is acidic, it is not conducive to the absorption of calcium by crabs and is not conducive to shelling. Therefore, water quality management is an important part of the entire crab breeding process and must be properly regulated. 1. Water quality regulation: In order to maintain the quality of water “new, live, tender and coolâ€, the dissolved oxygen in crab pond water quality reaches 5 mg/L, the transparency is more than 40 cm, the pH value is about 7.5, and the specific practice is to change the water from 5 days to 7 days. One time, the amount of water exchange is about 1/4 of the whole pool, and 2 days to 3 days of water injection in the high temperature season, especially in the crab shell phase, it is necessary to frequently inject water to promote the growth of normal crab shells; photosynthetic bacteria can also be used. , Bacillus subtilis and other microorganisms absorb hydrogen sulfide and ammonium salts in the water and the bottom of the toxic substances; use bottom modifiers to improve sludge at the bottom of the pool and decompose the harmful substances such as hydrogen sulfide and ammonia nitrogen in the sludge to increase dissolved oxygen and stabilize the pH value. Increase crab body immunity. 2. Water level regulation: The regulation of water level can be determined according to water temperature. In accordance with the principle of "super shallow, medium deep, and stable", water level regulation is carried out in three stages. From March to May, the water depth is controlled between 50 cm and 60 cm. From June to August, it is controlled between 1.2 m and 1.5 m (deepening the water level during the high temperature season). From September to October, it is stable at 1.0 m to 1.2 m. 3. Oxygenation measures: The main measure to increase dissolved oxygen in crab ponds is to use microporous oxygen and sprinkling of particulate oxygen, especially from mid-July to mid-August. In hot weather, the amount of dissolved oxygen in crab ponds is relatively low. Pay attention to oxygenation. The use of microporous aeration should be based on the situation of crab ponds and weather changes. From May to June, when the water quality and the weather are unfavorable, it is necessary to increase oxygen in a timely manner. After June, oxygen is increased from 12:00 to 15:00 at noon on sunny days. Depending on the actual situation in the morning, increase oxygen, and rainy days should be turned on in advance of oxygen; from September to October, the crab pool water quality is more fat, hot weather should be more boot oxygen. The length of time when the system is turned on and turned on should be flexibly controlled according to the weather, crab activities, and oxygen load. When oxygen-free equipment or oxygen-increasing equipment fails, dissolved oxygen is increased in the crab pond. Management of crab shells in the shell stage is an intrinsic physiological characteristic and an important indicator of crab growth, development, and metamorphosis. It can be said that in the life cycle of the crab, the more times its oyster shells grow, the faster the growth gains. The crab shell is a "reborn" process. The sturdy crabs can be completed in 5 minutes to 10 minutes, while the weak ones require about 1 hour. When crabs in shells are the weakest, they are also the most dangerous period to attack by pathogens, enemies, and even the same kind. Therefore, we must pay attention to the rules of crab shells in the daily management work. It is better to take one week before the crab shells. Change the water disinfection measures to ensure that the crabs are shelled. It is worth noting that in the case of sufficient feed, the number of crab shells increases accordingly and the growth rate increases accordingly. Disease prevention and control crabs have strong resistance to disease in the natural environment. However, in the case of artificial breeding, due to the high stocking density, the limited range of activities, and the defects in feeding and management methods, it is easy to cause diseases. Disease prevention and control of crabs is mainly controlled through drug prevention and treatment measures. Generally every 15 days to 20 days, quicklime 10 kg/667 sq.m.~15 kg/667 sq.m. of water is added to the solution and the whole pool is splashed once. It not only plays a role in disinfection and disease prevention, but also can supplement the growth of crabs. Calcium. Regularly add Chinese herbal medicine, photosynthetic bacteria, immune polysaccharides, Vitamins, and other drugs to the feed to make bait feeding, in order to enhance the crab body, improve crab body resistance, reduce the incidence of disease. Fishing 1. Fishing time: When the proportion of mature crabs in the gonads accounts for 80% of the river crabs, it is generally better to start fishing in mid-to late October. 2. Fishing methods: First, set up cages, crab cages and other tools in the pond to capture. This is also a method commonly used by farmers to catch crabs; the second is to use the water during the day and night drainage, using the habits of crab reproduction, in the out The water outlet is set up to catch the net; the third is to use the habit of crawling crabs to go ashore at night after discharging the pool water. When the river crab climbs to the side of escape prevention (net), artificial freehand is used to capture. Veterinary Drugs: refers to substances (including medicated feed additives) used to prevent, treat, diagnose animal diseases or purposefully regulate animal physiological functions.
Veterinary drugs mainly include: serum products, microecological products, Chinese herbal medicines, proprietary Chinese medicines, chemicals, antibiotics, and topical pesticides, disinfectants, etc.
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