The stocking time of crab seedlings and matters needing attention

1. Crab fry stocking time: March-May in spring is the time to put crab fry in the north and south, and it is the prerequisite for the recapture rate and stable and high yield of finished crab to package, transport and stock crab fry well in this period.

2. Precautions for stocking crab seedlings.

(1) Weather: Crab seedlings should be cultured in sunny weather, stable climate and little temperature change, so as to prevent a large number of crab seedlings from fleeing ashore on the day of stocking, which will affect the survival rate of crab seedlings.

(2) Water level: March-May is the suitable period for crab seedlings. Because of the large temperature difference between day and night, crab seedlings are easily stimulated, so the water level in the pond where crab seedlings are placed should be kept at about 80cm, which is conducive to reducing the stimulation of temperature difference to crab seedlings.

(3) Water quality: "Old water" is the best water quality for stocking crab seedlings. Because the algae and bacteria in the old water are stable, with little change and rich oxygen production, crab seedlings can adapt to their living environment as soon as possible after entering the pond, which is conducive to improving the survival rate. At the same time, crab seedlings cannot be kept in polluted pond water such as civil sewage, chemical water and pesticide residues.

(4) Seedling release method: When the crab seedlings go into the pond, the correct seedling release method should be adopted, commonly known as "disinfection and spitting water" method, that is, the crab seedlings should be put into a water solution container containing a certain amount of potassium permanganate or anti-stress drugs for 1-2 minutes, then taken out, waited for 3-5 minutes, and then put in again, three times in a row, and the interval increased by 2 minutes each time. In addition, preparation before stocking crab seedlings is also very important. When fertilizing and watering, the varieties of fertilizers should be reasonably selected, and trace elements such as nitrogen, phosphorus and potassium should be contained as much as possible.