How to select crab seedlings? How to cultivate scientifically?

The crab is delicious and nutritious. It has been a feast since ancient times. And the species of crabs are very rich, there are about 600 species in China, and their breeding areas are widely distributed. And crab farming also from the initial resource release culture, to the current intensive high-density breeding, the output value is as high as more than 10 billion yuan. Of course, the key to raising a good crab lies in the crab seedlings, so how to select the crab seedlings? How to cultivate scientifically? Let's learn more about it.

How to select crab seedlings?

Crab seedlings generally choose crab species with clean floor, strong vitality, hepatopancreas with small red dots, mainly local seedlings. When selecting seedlings, we should also pay attention to selecting crab seedlings with neat specifications, complete appendages, good vitality, yellowish and bluish back in the same batch. Then randomly take about 10 crab seedlings in the favored Miaotang and put them on a wet towel to keep them moisturized for one night. Pay attention to observe and see if there is any phenomenon of vomiting yellow and foam, so as to prevent crabs suffering from chronic intestinal diseases and being infected by bacteria.

How to cultivate scientifically?

1. Clear the pond and disinfect

Before releasing the seedlings, the pond should be drained, and then the bottom of the pond should be fully cleaned up. If there are still aquatic plants in it, the aquatic plants should also be cleaned up. There are plenty of ponds that have just been planned, and there is not much silt at the bottom of the pond. you can dig up the silt manually and reinforce the ridges after drying. In addition, disinfection work is essential, the more common pond cleaning drugs are pyrethroids, organophosphorus, chlorine preparations, quicklime and so on.

2. Stocking time and density

The time of releasing seedlings is generally from January to March, but in order to achieve higher yield, the density of releasing seedlings is generally up to 2000-3000 / mu (but high-density culture will bring great pressure to the water quality environment). If the crab species that have shelled off their shells for 1 or 2 times (spring release) are released through temporary culture, the amount of seed per mu will be about 600. If the conditions permit, it is better to put in when the water temperature reaches more than 8 ℃ after the beginning of spring.

3. Fertilizer and water preparation

Add a part of new water before seedling release, generally fertilizer and water once, fertilization is mainly EM bacteria, at the same time, the nutrition of fertilizer should be comprehensive to achieve a good fertilizer and water effect. 5-7 days before the release of seedlings, water and fertilizer will be up, the early temperature is low, fertilizer and water need many times to achieve the effect. After releasing seedlings, it is also necessary to apply fertilizer many times to stabilize the water quality.

4. Seedling releasing method

Crab seedlings, especially non-local seedlings, after long-distance transportation, physical decline, directly put into the pond stress, easy to go ashore, climbing and other phenomena. If you encounter unstable weather or rain during seedling release, it will often cause a large number of deaths. Therefore, it is recommended to put the seedlings on the edge of the pond to adapt to the temperature, and then use the pond water to sprinkle or soak the crab seedlings for 3-5 minutes, repeated 2-3 times, to make them spit out the mud or impurities above the stomach and gills to adapt to the water quality.

5. Scientific input

It should be fed in time after releasing seedlings. Most of the crab seedlings are not fed before transportation, and their physique is weak, so it is recommended to start feeding on the 5th day after release, mainly with opening material and fish paste to restore their physique and improve their resistance.

The correct release of crab seedlings before breeding is particularly critical, which is also the key to improve the survival rate of crab seedlings, and will eventually affect the income of breeding, so farmers should pay extra attention to it. In addition, there are many varieties of crab seedlings, so it is recommended to choose the best-selling local varieties.

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