Quality identification of river crab seedlings coming out of the pond

The quality of river crab seedlings coming out of the pond should be identified from eight aspects.

Buyers of crab seedlings should go to the nursery 15-20 days before the purchase to investigate the situation of raising seedlings, mainly to master the purity, source, individual size, health status, water body status of raising crabs, and to understand the metamorphosis of larvae, types of bait, medication, desalination methods, water temperature, salinity and decreasing range of seedlings, seedling age, and so on; on this basis, identify the quality of the seedlings. On the whole, the crab seedlings should meet the following quality requirements when they come out of the pond:

1. High-quality crab seedlings are bluish or yellowish brown in yellowish color; if the shell is transparent, white or dark black, it is a reflection of "too tender" and unhealthy.

2. the body surface is smooth and clean and does not stain, which is a sign of healthy seedlings; if the body surface and appendages are fixed or foreign bodies are born, it is an unhealthy performance.

3. Healthy seedlings swim horizontally in the water, and the speed is very fast; if the crab seedlings spin in the water or lie on their back at the bottom of the water, they are inferior seedlings.

4. Healthy crab seedlings can crawl quickly after leaving the water; if they gather together and remain motionless, it is a sign of poor vitality.

5. There are a large number of dead seedlings in the pond, and the survivors are also diseased seedlings.

6. After desalination and cooling at the age of more than 6 days, the specification ranges from 140000 / kg to 170000 / kg, with an even size of 80%-90%, all of which are high-quality seedlings.

7. If you grasp a handful of crab seedlings in your hand, you will feel stuck in your hand, hold them gently and then let them go. If you can quickly escape around, it will be a high-quality seedling.

8. Crab seedlings have bait in their stomach, but not much. Note that there should be no residual bait impurities and dead seedlings when the crab seedlings are weighed, and the seedlings should be weighed after draining water in the cage.