Which of the crabs have several forms of farming?

Crab farming refers to the development of edible species for listing crabs. In the Yangtze River basin, it is usually 2 years. Crab farming can be divided into the following forms according to different levels of water body and artificial control: (1) Crabs in ponds cultivate crabs in ponds, artificially control the whole process of breeding, and the rate of catching is high, but the specifications of outlet ponds And the meat quality is inferior to the large body of water crabs. According to farming methods can be divided into: 1 ponds are mainly raised by crab, with some fish. Generally about 50 ~ 75kg per mu, high-yield ponds produce up to 200kg of crabs. 2 fish and crab mixed with fish, with some crab species. Generally about 15kg of crab production per mu, high-yield pool up to 40kg. 3 ponds are raised. This is the catch of green crabs from natural water bodies or other ponds. Because they are soft and inexpensive, they have already matured in shells and are no longer shelled during the holding period, so they will not kill each other. . Therefore, the ponds are raised green crabs, and their survival rate is higher. Green crab was reared for 2 months to 3 months. The body of the crab was plump and full of gonads. The listing price was significantly increased. Its gross output per acre can reach more than 500kg, with significant benefits. However, this breeding method can only be carried out in areas where the crab resources are abundant. (2) Lakes, rivers, and crabs Species of crabs and crabs are cultivated in natural water bodies. Their environmental conditions are good. Natural baits are abundant and their cost is low. Crabs have large specifications and good quality. However, the rate of arrest is low. According to the current farming methods, it can be divided into: 1) The lake and river ditch species have been released for decades. This farming method has been in existence for decades. The lakes and rivers in the 60s and 70s were released by the crabs. In the 1980s, they were changed to freezer crabs. In addition to the stocking in recent years, In addition to crabs, they also stocked one-year-old crab species, all with significant results. However, this type of culture usually does not feed food, and its production results are greatly affected by natural factors. Stocking water requires good water quality, lush grasses, and smooth flow rates. Only a small number of outlets that communicate with the outside world have a good effect. Generally, the recovery rate of adult crabs is only 0.5% to 5%. 2 Lake nets Conserving crabs In the lakes, the waters with lush vegetation, good water quality, moderate water flow, and moderate water depth are selected, and the nets are enclosed in a certain area (a few tens of mu to several hundred mu). According to the growth requirements of crabs, Feeding intensive care. This breeding method draws advantages from ponds and lakes to raise crabs. The water quality is good, the activity space is large, the bait is abundant, the density is relatively thin, the size of the slaughtered crabs is large, the quality is good, and the rate of trapping can reach 40% to 60%, and the cost is low. High efficiency. Usually, the crabs can produce l5kg to 30kg per mu, and the high-yielding nets can hold up to 65kg per mu. (3) Grass swings, crabgrass reeds on the beach, and reed beach are suitable for the ecological requirements of crab growth. The production cost is low, the listing size is large, and the quality is good, but its catch rate is low. (4) Crabs raised in paddy fields The use of paddy fields to raise crabs is an emerging aquaculture industry that has developed in recent years. This method can not only make the paddy field less fertilize material, kill pests, remove weeds, but also increase the 1000-grain weight of rice. The rice paddy environment is slightly modified, and it also adapts to crab growth. Crabs grown in rice fields generally produce slightly more rice than crabs that do not raise crabs. They produce 20kg to 30kg of crabs per mu, and can produce up to 50kg to 75kg of crabs per mu in high-yield rice fields. The benefits are extremely significant.

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