Key points for attention in feeding crayfish for prevention of escape fishing

Crayfish stocking

Pond requirements: adequate water, good water quality, convenient access to and drainage, generally 3murs 5 mu. The ridge of the pool should have a certain slope, and in order to avoid crayfish escape, the width of the ridge should be more than 1.5m, and an anti-escape wall or board with a height of 0.5m and smooth inner wall should be set around the ridge. A number of mud ridges are built in the middle of the pond to create a burrowing place for crayfish. However, the two ends of the mud ridge are not connected with the pond ridge, the length of the mud ridge is about 4 × 5 of the pool length, the width of the ridge is more than 1 meter, and the ridge is 5~10cm higher than the surface of the water. The water depth of the pool should be 0.8-1.5 m, preferably in the middle, surrounded by shoals, tree roots and bamboo tubes at the bottom of the pool. Before stocking, strictly disinfect and apply 300 kilograms of rotten livestock and poultry manure per mu. The area of aquatic plants planted in the pond accounts for 30% of the pond area, such as bitter grass, verticillium verticillata, water hyacinth, water floating lotus, water peanut, etc., so as to facilitate crayfish to perch and avoid enemy attacks when molting.

The stocking of young shrimp: there are three main modes. First, it is released in summer, and the first batch of hatched shrimp is released in mid-late July, with 30, 000 to 40, 000 pieces of 0.8cm or more per mu. Second, it is released in autumn, and the large-size shrimp seedlings or shrimp species cultivated in the same year are released from mid-August to September. The size of shrimp fry is about 1.2cm, and there are 25-30 000 shrimps per mu. Shrimp species specification 2.5~3cm, 15 ~ 20 000 per mu. Third, it is released in winter and spring, and the shrimps that do not meet the market specifications are released in December or March-April of the following year. 15,000-20,000 shrimps per kilogram are released per mu, which are cultured in winter and spring and caught from June to July.

The young shrimp have strong physique, complete appendages, no injury, no disease, strong vitality, and the stocking specifications of the same pond should be the same. Before stocking, put the young shrimp into a plastic basin, slowly add a small amount of water to the basin until the water temperature in the basin is close to that of the pool, then add 3%-4% salt water according to the amount of water in the basin, soak and disinfect for 5 minutes, and then slowly put the young shrimp into the pool along the edge of the pool. When stocking, pay attention to avoid exposure. If the shrimp seedlings bought from other places are out of the water for a long time so that some shrimp are in a coma, the young shrimp should be temporarily reared in a water basin for 20 minutes before release.

Feed feeding: can be directly fed to minced fish, clam meat, silkworm pupa, earthworms, slaughterhouse leftovers, rice bran, bean cake, wheat bran, pumpkin, potato, fresh and tender aquatic plants, etc., and can also be fed with compound feed for shrimp, but the crude protein content of the feed should be kept above 25%.

The water temperature from July to October is suitable, which is the peak growing season for shrimps. The daily feeding amount is based on the fact that the shrimp is full, finished, and no residual bait is left. Generally, the animal feed accounts for 8%-12% of the shrimp body weight, and the dry feed or formula feed accounts for 3%-5% of the shrimp body weight. Feed is put into the shallow water by the pool, twice a day, once in the morning and evening, and 60% to 70% in the evening. In the rest of the season, it was fed once a day before and after sunset, and the daily feeding amount was 2% or 5% of the body weight of shrimp. The swimming ability of crayfish is poor, the range of activity is small, and it has the habit of occupying an area, so feeding should adhere to timing, fixed point, quality and quantity. In addition, feed feeding should pay attention to more when the weather is fine, less when high temperature and sultry, continuous rainy days or too strong water quality, less when a large number of shrimp molt, and more after molting.

Daily management: keep patrolling the pond every day and deal with problems in time. After one week of shrimp fry stocking, 50kg / mu of rotten livestock and poultry manure were applied, and 15kg / mu of fermented manure was applied every half a month in the middle and later stages of culture, keeping the pond water green or brown, with a transparency of about 35 thick meters. Change water frequently, change water every 5-7 days in high temperature season, usually change water every 15-20 days, each time the amount of water is 20%-30% of pool water, keep the pH value of pool water between 7-9, and the dissolved oxygen is more than 4 mg / L. Disinfect and improve the water body regularly, sprinkle the whole pool with 10 kg quicklime per mu every 15 days, and sprinkle the whole pond with 0.5 grams of bleach or 0.5 grams of disinfectant king per cubic meter of water every month. In the middle and later stages of culture, sprinkle 5 grams of photosynthetic bacteria and 40 grams of sediment improver on the whole pond every month to maintain a good water environment.

Fishing on the market: crayfish grow faster, after 3 to 5 months of breeding, adult shrimp specifications of more than 30 grams can be caught and listed on the market. There are many fishing methods, such as shrimp cage, casting net, pulling net or dry pond fishing. Fishing to catch the big to stay small method, can not meet the listing specifications to continue to stay in the pond to raise. It should be noted that drugs should be carefully used for disease prevention and treatment before fishing, otherwise the recapture rate of crayfish, the quality of commercial shrimp and the benefit of culture will be affected.