Identification method of inferior crab seedlings of hairy crab

Hairy crab culture is the key to successful selection of seedlings, high-quality crab seedlings can get twice the result with half the effort, then how to identify inferior crab seedlings? Inferior crab seedlings are mainly: drug damage seedlings, molting seedlings, flower seedlings, sea water seedlings, for sale seedlings, tender seedlings and high-temperature seedlings and so on.

Drug-induced seedling

Repeated use of oxytetracycline and other antibiotics in artificial breeding can cause crab seedlings to molt and metamorphosis into child crabs, the body can not absorb calcium, carapace can not harden, often swim to the edge of the pool to die in large numbers.

Molting seedling

If some of the crab seedlings have molted and metamorphosed into first-stage crabs, they can not be purchased, otherwise, a large number of crab seedlings will die after transportation.

Flower color seedling

The body color of crab seedlings is dark and light, and individuals are big and small. This kind of crab seedlings, if they are natural seedlings, may be mixed with other kinds of crab seedlings, which is common in natural seedlings. If it is artificial breeding, it is the irregular development of crab seedlings, which is easy to kill each other when molting.

Seawater seedling

The desalination of crab seedlings is not complete, and the seedlings are dark black. if they are directly cultured in fresh water, both natural and artificial seedlings will be in a coma to death.

Seedlings for sale

Some nursery units could not find a buyer in time after the crab seedlings were bred, so they could only keep the seedlings in the lower temperature breeding ponds. When the seedling preservation time is too long, a large number of bacterial protozoa enter the crab body. once the crab seedlings enter the culture pool with higher temperature, they will molt quickly, and most of the shell will fall off, but the old Gill filaments can not be shed completely, and the crabs can't breathe oxygen in the water and go ashore until they dry to death.

Tender seedling

The crab seedling is translucent and has a black line in the middle of the head and chest nail. This kind of crab seedling is young, the carapace is soft, and can not stand operation and transportation.

High temperature seedling

In artificial breeding, in order to shorten the breeding cycle and reduce the cost, raising water temperature is used to accelerate the abnormal development of crab seedlings. The crab seedlings bred at elevated temperature have poor adaptability to low temperature and the survival rate is low in the breeding stage.

Of course, in addition to the above common inferior crab seedlings, there are many ways to distinguish, which requires farmers to rely on their own breeding experience to identify.