What methods are there for identifying the quality of river crab seedlings when they are taken out of the pond?

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

Buyers of crab seedlings should, 15 to 20 days before purchasing seedlings, go to the seedling breeding farm to investigate and learn about the breeding situation, mainly to understand the purity and mixing, source, individual size, health status of the parent crabs, and the condition of the breeding water body; after the start of hatching, also learn about larval metamorphosis, bait types, medication use, desalination methods, breeding water temperature, salinity and its rate of decrease, seedling age, and many other circumstances; on this basis, then identify the quality of the seedlings. Overall, when river crab seedlings are taken out of the pond, they should meet the following quality requirements:

1. High-quality crab seedlings are yellow with a hint of green, or yellow-brown; if the shell color is transparent, whitish, or deep black, it reflects being "too tender" and not robust.

2. A clean body surface with no contaminants is a sign of healthy seedlings; if the body surface and appendages have attached Epistylis or foreign matter, it is a sign of poor health.

3. Healthy seedlings swim horizontally in the water, very quickly; if the crab seedlings spin in the water or lie on their backs at the bottom without moving, they are inferior seedlings.

4. Healthy crab seedlings can quickly crawl after leaving the water; if they gather into a clump and do not move, it is a sign of poor vitality.

5. If there are a large number of dead seedlings in the pond, the ones still alive are also diseased seedlings.

6. After more than 6 days of desalination and cooling, with a size of 140,000 to 170,000 individuals per kilogram and a uniform size proportion of 80% to 90%, they are all high-quality seedlings.

7. Grab a handful of crab seedlings; if they feel prickly to the hand, and when lightly held and then released they quickly scatter in all directions, they are high-quality seedlings.

8. The crab seedlings should have bait in their stomachs, but not too much; note that when weighing the crab seedlings there should be no residual bait, impurities, or dead seedlings, and the seedlings should be weighed after draining water in a net cage.