(1) The choice of fence area The lake net enclosure crab should have the following conditions: 1 The waters are open, the water quality is good, and the water flow is slow and smooth. 2 Suitable water depth, perennial water level 1m ~ l.5m, water level drop is small. 3 The bottom of the lake is flat, with clay and hard mud as the bottom, and less organic matter in the mud. 4 With dense grasses, natural bait is rich in resources and less predatory creatures. 5 It does not affect the irrigation of surrounding farmland, water storage, flood discharge, and navigation of ships. The environment is quiet and transportation is convenient. (2) Net construction A mesh net of 1 cm to 1.2 cm polyethylene mesh was used as a fence and bamboo was used as a pile. Surrounding the delineated aquaculture area for piling and hanging nets, each lm ~ 1.5m a pile, the bottom of the net is fixed with a gabion and ground anchors, so that the net foot is closely attached to the bottom mud and sank into the bottom mud, the upper part of the net is higher The surface of the water is lm ~ 1.5m, and a 0.5m to 0.7m inward tilted net is installed at the top to prevent the crab from crawling out of the net. The general net area is 30 mu to 100 mu, with a maximum of 1,000 mu. A net fence area is usually built outside the culture area to ensure safety. There are also bamboo foils instead of mesh sheets to form a foil enclosure. Each bamboo piece of bamboo foil is relatively firm in the mud, and it is not easy to be bitten by the crabs. The thicker lakes have good resistance to lodging, but the service life is short and the production time is short. The net enclosure is easy to make, but it is resistant to lodging. (3) Planting aquatic plants to protect aquatic resources The number of plants in lakes and nets not only directly affects the quantity, size, and quality of crabs, but also relates to the key measures for the sustainability of the development of crabs. The fisherman has: “The size of the crabs, watching grass, crabs, watching grasses†is a very figurative metaphor. In order to protect the water and grass resources of the lake, it is necessary to protect the plants outside the fence, so that Heli can develop and use it; on the other hand, plants must be planted within the fence. The method is to use a mesh to divide the net into two parts. First half of the water is used to store the crab species, and the other half is to plant the aquatic plants. At present, most plants are planted with hardgrass. Per acre net surrounding the water surface, with Vallisneria seed 30g ~ 50g, Vallisneria cultivation methods with rice mulching. When the bitter grass grows to about 10cm in length, the rice is thrown into the water, and the bitter grass is planted in the net enclosure of the other half of the unreleased crabs until it grows to about 30cm. The separated mesh is removed and the river crab enters the aquatic grass area. You can. (4) Crab species stocking The crabs are best stocked at about 10°C in March. At this time, the temperature is low, the survival rate of transportation is high, and the stocking specification is 80 to 200/kg of wintering crab species. Normally, 0.7 to 1 crab species are stocked per square meter of water. Crabs are generally used for polyculture. The stocking of fingerlings is still carried out according to the rules. However, grass carp should be banned on the stocking structure to limit the stocking of head lice, and a part of squid, slender scales, slugs and squid should be added to ease the competition of fish and crab.