It is recommended to raise crabs with snails in ponds.

With the expansion of the scale of crab culture and the improvement of the degree of intensive culture, the water quality of cultured waters deteriorated, the quality of river crab decreased, the disease aggravated, and the benefit of river crab culture was affected. Dalong Township, Dafeng City, Jiangsu Province has adopted the method of recommending and putting snails to cultivate river crabs in recent years, and achieved a good result of producing 55 kilograms of crabs with an area of 667 square meters. The practice is as follows.

1. Pond requirements. It is required that the water quality is fresh, the water depth is more than 1.5 meters, the bottom is flat, the silt is less than 20 centimeters, and the area is 0.67-1.33 hectares. The inlet and outlet of the crab pond are set diagonally to implement high irrigation and low discharge. A calcium plastic board is used around the pool to prevent escape. A temporary pond is arranged at the deep water in the corner of the pond (a flat bottom, and a temporary pond with a depth of 50-60 cm can be excavated at the corner or edge of the pond), which accounts for 5% of the total area of the pond. 10%.

2. Clean up the pond. Dry pond exposure in December, remove the excess silt from the bottom, sort out the ridges of the pond, and disinfect the pond with 75 kilograms of quicklime every 667 square meters 15 days before the crabs are planted.

3. Crab species selection, purchase and stocking. The selected young crabs require the same specifications, complete appendages, no disease, no injury, and immature sex. Before and after the Spring Festival, every 667 square meters of pond stocking specifications for 100-200 kilograms of young crabs 500 murmur600. The young crabs were first put into the temporary pond for temporary cultivation, and the water peanuts were transplanted in the pond to provide shelter for the crabs. The water peanuts were disinfected with 20 grams / cubic meter of lime water before transplantation.

4. Aquatic plant cultivation. Sow bitter grass before and after the Qingming Festival. Soak the seeds for 12 hours before sowing, wash the mucus off the seeds, mix them with fine soil or sand and sow in the whole pool, sowing 50 grams per 667 square meters. After the seeds are put into the pond, the water in the pond is controlled within 20 centimeters, which promotes the seeds to germinate and tiller early to meet the growth needs of river crabs in the future. With the rise of water temperature, the water level of the pond can be deepened to 60-80 cm, which makes the aquatic plants grow longitudinally, become a place for river crabs to molt and hide, and can absorb excess nutrients, purify water quality, shade and cool down, and provide bait.

5. Snail release. Before and after the Qingming Festival, 150 kg-200 kg of live snails are put in every 667 square meters. Snails should be disinfected before release. The advantages of snails are: (1) snails feed on the leaves of aquatic plants and benthic algae, which can purify water quality; (2) snails reproduce quickly and can be used as bait for river crabs; and 3) snails have low cost and a wide range of sources. Combined with planting bitter grass can better control the water quality of the pond and provide a fresh living environment for river crabs.

6. Daily management. When the young crab is released, the water temperature is low, and the young crab consumes physical energy after overwintering. For this reason, the early stage should mainly be fed with nutritious pellet bait, properly matched with some animal bait, and fed once a day in the evening. In May, with the rise of water temperature, the river crab entered a prosperous period of growth, feeding two times, mainly full-price river crab feed, and the feeding amount was finished within 2 hours. More plant bait should be given in the high temperature season from July to September to facilitate the accumulation of physical fitness of river crabs.