What are the common breeding methods of crabs?

Adult crab culture refers to the development of edible specifications of crab species on the market. In the Yangtze River basin, it is usually 2 years. Adult crab culture can be divided into the following forms according to different water bodies and artificial control degrees:

Raising crabs in pond

The whole process of crab culture can be controlled artificially in the pond, and the recapture rate is higher, but the size and meat quality of the crab culture in the pond is inferior to that in the large water body. According to the mode of culture, it can be divided into:

1. Monoculture in the pond: mainly crabs, with some fish. Generally, the yield per mu is about 50~75kg, and the yield of adult crabs per mu in high-yield ponds can reach 200kg.

2. Mixed culture of fish and crabs: mainly fish, with some crab species. Generally, the yield of adult crab is about 15kg per mu, and the high-yield pond can reach 40kg.

3. Pond temporary culture: green crabs are caught from natural water bodies or other ponds. Because of their thin shell, soft shell and low price, they have completed mature molting and do not molt during the temporary culture period, so they will not kill each other. Therefore, the survival rate of green crabs raised temporarily in ponds is higher. After raising green crabs for 2 months to 3 months, the crabs are fat, the gonads are full, and the market price is significantly increased. Its wool yield per mu can reach more than 500kg, and the benefit is remarkable. However, this culture method can only be carried out in areas where adult crabs are rich in resources.

Raising crabs in lakes and ditches

Crab species cultivated in natural water bodies have good environmental conditions, sufficient natural bait, low cost, large market size and good quality. But the recapture rate is low. According to the current culture methods, it can be divided into:

1. Release of crab species in lakes and ditches: this breeding method has a history of several decades. In the 1960s and 1970s, crab seedlings were released in lakes and ditches; in 1980s, young crabs were released; in recent years, in addition to young crabs, one-year-old crabs were also released, all of which had obvious results. However, this kind of culture method usually does not use bait, and its production result is greatly affected by natural factors, so it still belongs to rough culture. Stocked water requires good water quality, lush water plants, slow flow rate, few nozzles connected with the outside world to have better benefits, generally the recapture rate of adult crabs is only 0.5% and 5%.

2. Crab culture in lake net: select the water area with lush grass, good water quality, gentle flow and moderate water depth in the lake, and arch it into a certain area (ranging from tens of mu to hundreds of mu). According to the growth requirements of river crab, bait intensive culture. This culture method absorbs the advantages of raising crabs in ponds and lakes, which has the advantages of good water quality, large activity space, sufficient bait, sparse density, large size, good quality, recapture rate of 40% and 60%, low cost and high benefit. Usually, adult crab l5kg~30kg can be produced per mu, and high-yield net crab culture can reach 65kg per mu.

Crab culture in Caodang and Lutan

Caodang and Reed beach are suitable for the ecological requirements of river crab growth, with low production cost, large listing specifications and good quality, but their recapture rate is low.

Raising crabs in rice fields

Raising crabs in rice fields is a new aquaculture industry developed in recent years. This method can not only reduce the application of fertilizer, kill insect pests and weeds in rice fields, but also increase the 1000-grain weight of rice, slightly improve the environment of rice fields and adapt to the growth of adult crabs. Generally speaking, the yield of rice in crab rice field is slightly higher than that in rice field without crab culture, the yield of adult crab per mu is 20kg~30kg, and the yield of adult crab per mu in high-yield paddy field can reach 50kg~75kg, and its benefit is very significant.