What are the advantages of hairy crabs releasing crab seedlings in winter? How to raise hairy crabs?

Hairy crab is a kind of river crab, which is widely distributed along the long coastline from the Liaohe River to the Pearl River in the north of China, among which the Yangtze River system has the largest yield, the most delicious taste and rich nutrition. Generally speaking, hairy crab especially refers to the Chinese mitten crab of the Yangtze River system. Hairy crab culture has the advantages of low investment and high efficiency, which is a good way to get rich. In recent years, hairy crab production has developed rapidly. Many farmers take it for granted that spring is more suitable for hairy crab seedlings, but it is not. The advantages of putting hairy crab seedlings in winter are mainly reflected in the following aspects.

1. Advantages of releasing crab seedlings in hairy crab culture in winter

1. the price is cheap

The period from mid-October to mid-November is the period when a large number of crab seedlings are caught, transferred to the pool to survive the winter and sold. During this period, the price is low, usually about 1 yuan each, while in spring, the price of each crab seedling is up to 2 yuan ~ 3 yuan.

2. Transportation safety

The newly caught crab seedlings are rich in fat, strong physique, strong adaptability and resistance, and at this time the temperature difference between the north and the south is only 5 ℃ ~ 10 ℃, the air humidity is large, it is easy to operate, the management is simple, and the transportation is safe and reliable; while the crab seedlings after overwintering are weak, poor resistance, coupled with the large temperature difference between the north and the south, easy to suffer from a variety of diseases, low transport survival rate, and higher transport conditions.

3. High survival rate

In winter, due to the clean water quality and the weakening of bacterial and viral activity, the chances of crab seedlings being infected by various bacteria are reduced, while in spring, crab seedlings are invaded by a variety of bacteria and reduce the survival rate.

4. Long growth period

The growth period of spring crab seedlings is only more than 6 months, except for the adaptation period, the growth period is shorter, the individual is small and the yield is low. Putting crab seedlings in winter can generally prolong the effective growth period of 1 ~ 2 months, which has a significant effect on increasing specification, increasing yield and increasing benefit.

2. Culture techniques of hairy crabs

1. Plant aquatic plants well

In order to cultivate hairy crabs, we should first plant aquatic plants, which is one of the natural bait of hairy crabs, and can play a good role in purifying water quality, and it is also a place for hairy crabs to perch and avoid enemies. It is mainly algae. You can also put in an appropriate amount of field snails. For more aquatic grass planting, you can read the article "planting and maintenance techniques of aquatic plants in crab ponds".

2. Rational stocking

The crab seedlings should be disinfected before release, separated evenly according to size, and put in the water with a purse seine, so that the crabs can adapt to the environment for 1 month before the purse seine can be removed. In general, crab breeding should achieve the principle of "three suitability" and "one temporary breeding". That is, appropriate density, timely stocking, moderate specifications and temporary stocking before stocking. When stocking, the water should not be too deep, it is appropriate to use 1.5 Mel 2 meters, and the temperature should be 25 degrees 20 Mel.

3. Stocking density

In the environment of luxuriant water plants and fresh water quality, the general specification is about 300 per mu, so that hairy crabs have a sufficient living and growing space. The stocking time of crab species is generally from the end of February to March every year. If the crabs are released prematurely, the overwintering casualties will be more serious, the water temperature will rise too late, and some river crabs will molt, which will affect the survival rate of the lower pond.

4. Daily pond patrol

The main purpose of patrolling the pond in the morning is to check whether there is residual bait in order to arrange the bait for that day; at noon, the main purpose of patrolling the pond is to measure the water temperature and observe the color of the water and the changes of the water; and in the evening and night, the main purpose of patrolling the pond is to observe the activity and eating of river crabs, and take timely measures to find problems.