How to avoid temporary culture of river crabs on the market to prevent the death of river crabs

In order to avoid the low price of centralized listing, many farmers are not in a hurry to sell river crabs during the harvest season, but temporarily raise them to be listed around the Spring Festival in order to make greater profits. However, many river crabs fell ill seriously during the temporary recuperation period, died in large numbers, and suffered great economic losses. Crab farmers put forward the corresponding countermeasures through the analysis of the causes of death of temporary river crabs for your reference.

Temporary culture of river crab

First, the cause of death:

The main results are as follows: 1. The temporary culture density is high: some farmers temporarily raise river crabs up to about 500 kg per mu, and some river crabs need to complete their last reproductive molting in the temporary culture pond. however, due to the limitation of temporary culture environment, insufficient feed and high stocking density, some river crabs failed to return shell and died, and some river crabs died when they molted.

2. Cage temporary cultivation: some crab households temporarily raise river crabs in cage, because the cage mesh is not only a climbing attachment of river crabs, but also a place where river crabs break their appendages. When the density is high, many river crabs die because of foot breaking and loss of protective ability.

3. management can not keep up with: in order to save money, the temporary culture pond can not provide hidden artificial nests for river crabs, nor can they inhabit or feed on aquatic plants, and their protection ability is reduced after the last molting.

4. Temporary pond desilting is disadvantageous: many crab farmers use adult crab ponds or summer flower fish ponds to temporarily raise river crabs, generally without desilting, the silt is rich in pathogenic bacteria, temporary culture of river crabs has poor disease resistance and is prone to disease and death.

5. The Gill filaments of river crabs are damaged and lose too much water: many people buy river crabs and then raise them temporarily, but the river crabs leave the water for a long time, the Gill cavity and Gill filaments are seriously damaged, and they lose too much water, which leads to the death of river crabs.

II. Preventive measures

1. Build a temporary pond: the temporary pond has sufficient water source, no pollution, rich dissolved oxygen and less silt deposition. 5-10cm is suitable. The pond is rich in aquatic plants with an area of 2-3 mu and a water depth of 0. 8-1 meter. Do not temporarily raise river crabs in cages unless they are sold in a few days, but water peanuts should be kept around the cages.

2, clear pond disinfection: temporarily raise river crabs into the pond half a month, per mu with 75 kg quicklime with water cleaning pond disinfection (water depth 10-15 cm).

3. Suitable density: temporary culture density is 150-200 kg per mu. Before entering the pond, river crabs should be checked one by one to get rid of disabled crabs, dying crabs and dead crabs, and it is best to raise them in large, medium and small ponds.

4, easy to operate, early prevention of diseases: when fishing for river crabs, the action should be light, do not damage the feet of river crabs. During the temporary rearing period, if the crab's abdominal appendages are rotten, the anus is red and swollen, and it refuses to eat, it can be fed with oxytetracycline and crab Kangning Ⅱ.

5. The time should be short: the temporary rearing period of river crab should be one and a half to two months. When the water body is small, the water quality is poor, the water exchange is slow, and the temporary culture density of river crab is high, the temporary culture time should be shortened.

6. Strengthen management: keep the water quality fresh, increase oxygen and change water in time, feed palatable feed and supplement vitamins to ensure the health of river crabs.