The influence of continuous overcast and rain on aquaculture and its countermeasures?

The influence and countermeasures of overcast and rain for more than 20 days in midsummer on aquaculture, especially the influence and countermeasures of Macrobrachium rosenbergii and South American shrimp which have been listed one after another. Continuous rain, sometimes thunderstorm and muggy weather, low pressure, increased excreta of farmed animals, water quality is easy to deteriorate, and particularly prone to hypoxia, but also easy to cause drug accidents. In the Meiyu period, there will be a variety of disease problems, and the risk is also great to deal with, serious cases may lose a lot. Therefore, this period is a dangerous season for changeable water quality, disease outbreaks and epidemics. The majority of aquaculture farmers should always pay attention to weather changes and actively do a good job in aquaculture management. 1. Strengthen the control of water quality. During this period, the food intake of fish and shrimp increased, and the accumulated residual bait and excrement increased, so the water quality was easy to deteriorate at this stage, resulting in hypoxia or lack of dissolved oxygen. Therefore, water quality control is the technical key at this stage. Several specific points should be done: (1) We should often add new water, constantly raise the water level, and properly replace part of the bottom water. (2) turn on the aerator frequently, especially at night and in the latter part of the night. In case of showers, continuous muggy or sudden weather, the start-up time should be extended and particulate oxygen should be used in conjunction with it. As far as possible, granular oxygen should be used once every 2-3 days in shrimp culture ponds. (3) for ponds without aerators, it is recommended to use granular oxygen every 3-5 days (best in the latter part of the night) to increase dissolved oxygen at the bottom and reduce the production of harmful substances at the bottom. If the culture density is high and the water quality is unstable, the use frequency should be increased. (4) use beneficial microbial preparations such as EM, Baoyuan, Huoshuibao, Daijiajing and other beneficial microorganisms and sediment improvers to improve water quality and sediment quality. It can be used at the same time with granular oxygen once every 7 to 10 days, which can eliminate the harmful substances caused by the decomposition of organic matter at the bottom, restrain the reproduction of bacteria, maintain good water quality and prevent the deterioration of sediment. (5) it is overcast and rainy, and the transparency of the pool water is often not high. Biological agents such as photosynthetic bacteria and quick-acting Shuijingbao can be used to increase transparency, purify water quality and prevent water deterioration. Culture density is relatively large, the pond water is relatively deep, but also should sprinkle lime milk appropriately, 1 meter water depth per mu use 4 kilograms. However, saline-alkali ponds and ponds with high pH value do not need this treatment. 2. Ensure the feed quality and control the feed quantity. It is necessary to ensure that the feed is fresh and does not deteriorate. Formula feed should pay attention to anti-mildew deterioration, the amount of purchase should not be too much. Black fish, perch and other aquaculture should reduce the feeding of chilled bait, so as not to pollute the water quality. The feeding amount should be flexibly controlled according to the weather, water quality changes and the actual feeding situation, and should be reduced in case of muggy and showering weather, so as not to cause stomach vomiting, such as fish and shrimp. The amount of feeding in the plum rain season is generally controlled when the fish and shrimp are 7-80% full. 3. Do a good job in disease prevention and control of disease occurrence. During this period, the main diseases of fish are hemorrhagic disease, enteritis, Gill rot disease, white head and white mouth disease, white skin disease, so fish mycelium, allicin and Sanhuang powder (1%) were added to the feed for about 5 days. River crabs are mainly ciliates, black Gill rotten gills, carapace ulcers, enteritis, norfloxacin powder plus toxicol (1%) can be fed continuously for 3 weeks for 5 days. Three to four days after insecticidal disinfection, compound bacillus and Dijiajing combined with granule oxygen can be used to improve the stable water environment. During the period of Meiyu, Vc, multivitamin, allicin (easy to develop enteritis in Meiyu season), live bacteria (EM bacteria, Bacillus), Sanhuang powder of traditional Chinese medicine, immune polysaccharides and so on can be added to the feed to improve the digestive ability of farmed animals, enhance the ability of anti-stress and enhance the ability of disease resistance. For Penaeus vannamei in the plum rain season, overcast and rainy, thunderstorm and muggy weather changes have a great impact on its culture ecological environment, which is very easy to cause stress reaction and cause disease. Recently, there are many cases of Penaeus vannamei, and the epidemic is widespread. The following points should be done as a top priority for shrimp farmers' reference.