How to prevent crab diseases in winter? Six practical methods to master

First, freeze and sun-dry the pond bottom. After the crab pond is cleaned, clear the drainage ditches, use machinery to pump water regularly, and try to let the pond bottom undergo severe freezing and sunlight exposure for about one month, so as to improve the soil condition of the pond bottom and allow some pathogens to be killed by freezing and sunlight exposure, creating a good ecological environment for the future growth of crabs.

Second, remove the sludge at the bottom of the pond. The main components of sludge are a large amount of residual bait, organic matter, dead bodies and biological excrement. Excessive sludge easily causes water quality deterioration, and also produces a large amount of organic acids, hydrogen sulfide, ammonia, etc., which lowers the pH value of the pond water, inhibits and harms the growth and survival of river crabs. In particular, harmful bacteria, parasites and other pathogenic microorganisms exist in the sludge. Once conditions are suitable, various pathogens will cause disaster.

Third, carry out drug disinfection. 20 days before stocking crab seedlings, use quicklime, bleaching powder, etc. for strict disinfection. For quicklime disinfection, use 75 kg to 100 kg per mu, dissolve the quicklime in water and splash it over the whole pond. For bleaching powder disinfection, use 15 kg to 20 kg per mu.

Fourth, build a good inlet and drainage system. In addition to considering sufficient water flow, water physical and chemical factors suitable for crab growth, and freedom from pollution and pathogens, attention should also be paid to mutual infection and repeated infection caused by using the same ditch for inlet and drainage. Therefore, each crab pond is required to be able to discharge its pond water separately.

Fifth, transplant aquatic plants. Aquatic plants can provide river crabs with habitat and a molting environment, and can also provide them with fresh and delicious plant-based feed and reduce the ammonia nitrogen content in the water, increase oxygen, and improve water quality. Among aquatic product species, submerged plants include tape grass, small naiad, etc., and floating plants include water hyacinth, duckweed, etc. These plants should be sown, transplanted or moved in winter and spring, so that the coverage rate of the crab pond reaches more than 60%.

Sixth, disinfect the crab bodies well. Before the crab seedlings are put into the pond, disinfect them with suitable drugs. Commonly, soak them in potassium permanganate at a concentration of 15 mg to 20 mg per liter for 20 minutes to 30 minutes, or soak them in a bleaching powder solution at a concentration of 10 mg per liter for 10 minutes to 15 minutes.