In recent years, the ecological culture mode of interplanting rare fish in crab ponds has been popularized in the main culture areas of river crabs, and remarkable ecological, economic and social benefits have been achieved.

(1) culture conditions

(1) Pond conditions: A normal natural breeding pond or a water-lifting pond reconstructed by digging ditches around low-yield farmland requires quiet environment, sufficient sunshine, convenient irrigation and drainage, and convenient land and water transportation. The water source is abundant, and the water quality is fresh and pollution-free, which meets the standard of NY 505 1-200 1.

(2) Facilities: the escape wall is made of cement board and aluminum board, supported by bamboo piles, and stitched with fine iron wire. The upper soil is 0.5-0.7m, the lower soil is 0.2-0.3m, and the four corners are curved. Both ends of the pond are respectively provided with a water inlet and a water outlet. The water inlet is located on the interface of the highest water level and extends into the pool with cement culvert pipes; The water outlet is opposite to the water inlet. The water inlet and outlet are sealed with barbed wire to prevent escape. The water inlet needs to be equipped with a pipe bag made of screen wire to prevent harmful organisms from entering with the water. There are 1 ~ 2 tons cement boats in the big pond, which are used for feeding, fertilization and management. At the same time, it is equipped with facilities such as water pump, aerator and duty room.

(3) Setting up a temporary breeding area: Set up a temporary breeding area with a total pond area of110 ~1/5 in the middle of the pond, which is used to temporarily raise crab species before planting grass, and leave around May after the aquatic plants grow vigorously.

(2) Stocking mode

(1) Dredging and disinfection: put the fish fry in front of the dry pond, remove excess sludge, expose or freeze for 15 ~ 20 days, filter and inject 30 ~ 50 cm fresh water, and spray the whole pond for disinfection after dissolving with 100 ~ 150kg quicklime per mu.

(2) Fertilization and hydroponics: add a small amount of quicklime to the decomposed organic fertilizer, pile it at a depth of 30-40 cm, cover it with sediment, and slowly release it in the pool. You can also use pollution-free clean fertilizers, such as compound fertilizer and long-acting fertilizer. The amount of fertilization is flexibly controlled according to the situation of pool water and sludge. Generally, organic fertilizer is applied per mu 100 ~ 200 kg.

(3) Planting grass and throwing snails: planting Elodea philoxeroides and sowing Sophora alopecuroides around February, planting Elodea philoxeroides with grass stems in the soil, mixing fine soil and Sophora alopecuroides with grass seeds and scattering them at the bottom of the pond. Generally, Elodea nuttallii is planted with a width of1~ 3m, leaving a blank zone of about 2m. Sowing Sophora alopecuroides with a width of1~ 3m and 1 ~ 2 months can germinate. Before Qingming Festival, put fresh snails in the culture area, with an area of 300-500 kg per mu.

④ fry stocking: see table 5-2.

Table 5-2 fry stocking table of crab-fish interplanting mode

Table 5-2 fry stocking table of crab-fish interplanting mode (continued)-1

(3) Daily management

① Bait feeding: The bait varieties include mussel meat, snail meat, small fish and shrimp, wheat, grains, cakes, pumpkins, sweet potatoes, aquatic or terrestrial fresh grass, etc. , you can also use full-price compound feed. According to the weather, water quality, natural bait quantity and various aquaculture varieties, it is estimated that the water storage capacity of the pond in a certain stage and growing season can be flexibly grasped. The Chinese mitten-handed crab adopts the way of "thin at both ends and thick in the middle", combining meat and vegetables, reasonably matching, and feeding at a fixed point, every afternoon 1 time, and checking the next day, the surplus is reduced and the shortage is increased. Generally, the daily feed amount is arranged according to about 7% of the weight of pond crabs. Polyculture species mainly use the feed and residual bait of crabs and fish, and generally do not feed them specially.

② Water quality management: First, water quality requirements. The transparency is 30 ~ 50 cm, and the water color is crisp yellow-green. Dissolved oxygen is greater than 5mg/L, pH value is 7 ~ 8, neutral and alkaline, ammonia nitrogen is less than 0.2mg/L, nitrite is less than 0.02mg/L ... The second is water level. Adhere to the principle of "shallow logistics in the front", that is, keep shallow water level in the early stage to raise water temperature and promote molting; In the mid-term, especially in the hot summer and autumn, it is necessary to maintain the deep water level, keep the water fresh and have sufficient dissolved oxygen. The third is to add water to the water. When the water is naturally eroded and the water level is too shallow, water should be added in time; When the water quality is too strong, fresh water should be replaced in time, especially in summer and autumn. The fourth is chemical and biological regulation. Spray quicklime water on the whole pond regularly, and use biological agents such as photosynthetic bacteria, EM bacteria and Bacillus subtilis.

③ Disease prevention: the released crab species are disinfected with potassium permanganate or salt, and the fish species are disinfected with bleaching powder or trichlorfon 10 ~ 30 minutes. Applying quicklime 1 time every 20 days and 5 ~ 10 kg per mu in the growing season can not only disinfect and prevent diseases, but also improve water quality, adjust pH, increase calcium and promote the molting growth of crabs and shrimps. During the growing season, medicinal bait 1 time (feed 50 kg, allicin 25 g, twice a day for 3 days) was added. In addition, fertilizers, aquatic plants and tools are often disinfected with bleaching powder.

④ Fishing and temporary rearing: crabs are caught after 5,438+10 in June, and the caught river crabs are temporarily reared in crab boxes for sale. Green shrimps are listed in rotation, and adult shrimps over 4 cm are regularly caught and sold to prevent death after sexual maturity and reproduction. Siniperca chuatsi, Pelteobagrus fulvidraco and culter ilishaeformis were harvested in dry ponds at the end of the year.

(4) Key points and matters needing attention in aquaculture

① Pay attention to planting grass and throwing snails: Aquaculture in ponds can not only increase hidden places, but also serve as plant bait. Aquatic plant species include Sophora alopecuroides, Hydrilla verticillata, Elodea nuttallii and Alternanthera philoxeroides. The coverage area of aquatic plants is 60% ~ 70% of the pond area, and the redundant aquatic plants should be removed, especially Elodea nuttallii, which grows vigorously and is easy to block the water surface, especially in the later period, the channels should be cleaned regularly. Snails are high-quality natural basic bait for crabs. When they give birth to crabs in water, they can not only purify the water quality, but also become fresh bait for crabs to feed freely. During the feeding period, the crab should be properly supplemented according to its food intake.

(2) Feed bait reasonably: Siniperca chuatsi, Pseudobagrus fulvidraco and Crouching Red Catfish are all fierce carnivorous fish, but their food structures are different. Siniperca chuatsi lives on fresh fish and shrimp, and mainly eats bottom fishes, such as crucian carp, loach and arhat fish. Pelteobagrus fulvidraco not only eats fresh fish and shrimp in crab ponds, but also eats artificially fed snails or a mixture of fish paste and plant feed; In the crab pond, Erythroculter ilishaeformis mainly feeds on small pelagic fish, such as silver carp and summer carp, and also feeds on artificially fed dead fish or frozen fish pieces. Therefore, in the mixed culture of crab ponds, in order to improve the yield and specifications of rare fish, bait can be properly fed.

③ Use drugs with caution: Siniperca chuatsi and Pelteobagrus fulvidraco are sensitive to drugs. When using fishery drugs, we should be selective and calculate the dosage accurately, especially in high temperature season, and we should use them with caution, generally with low dosage or without drugs. The drugs used in the whole process of breeding must meet NY 507 1 standard. Siniperca chuatsi is prone to hypoxia floating head, and serious floating head will lead to total annihilation, so the water quality should not be too fat. It is the key to the success of polyculture to replenish fresh water regularly and keep the pool water fresh and high dissolved oxygen.