The high temperature season has many hazards to aquaculture management. How should we prevent it?

Since late July, there have been continuous high-temperature weather above 35°C, and dead fish and crabs have occurred in some pond entrances. In order to ensure the healthy growth of aquatic products in ponds, based on the current climate and production characteristics, the following suggestions are made for farmers' reference. 1. Strengthen water quality regulation and keep water fresh. Add new water in a timely manner to raise the pond water level. When adding water, drain the water first and then add water. The appropriate time is in the early morning, so that the water level in crab and shrimp ponds should be controlled at about 1 meter, and the water level in conventional fish ponds should be controlled at more than 2 meters. At the same time, the entire pond is splashed with substrate improver, Bacillus, photosynthetic bacteria and other biological agents every 5-7 days.

2. Control the number of aquatic plants and strengthen aquatic plant maintenance. The total amount and density of aquatic plants in river crab ponds must be strictly controlled. If the pond mouth is covered by more than 60% of the pond mouth, part of the aquatic plants must be removed in time with a drag knife at intervals. Cut off the elodea that exceeds the water surface and keep it under 30 centimeters. For crab ponds where aquatic plants are seriously damaged in the early stage, water peanuts should be transplanted in time.

3. Turn on more aerators at the right time to ensure sufficient dissolved oxygen in the water. On sunny days, it can be turned on for 2-3 hours from 1:00 to 3:00 pm, and then turned on for 4-6 hours after 10:00 pm. It can be turned on all day long on muggy, cloudy and rainy days.

4. Reduce the amount of feeding appropriately and grasp the feeding time. After continuous high-temperature exposure, the water temperature generally exceeds 30°C, and the appetite of fish, crabs, etc. decreases, so the feeding amount should be reduced and the amount should be controlled at 70-80% of the usual amount. The recommended feeding time is 7:00-8:00 in the morning and 5:00-6:00 in the afternoon.

5. Strengthen disease prevention and control the occurrence of diseases. During the high temperature season, regularly adding Chinese herbal medicine, immune polysaccharides and vitamins to the feed can effectively increase immunity and prevent diseases.

6. It is forbidden to spray disinfectant drugs. During high temperature seasons, avoid using irritating disinfectant and insecticides such as bleaching powder and copper sulfate, and eliminate the use of algae-killing drugs to maintain a stable pond ecology. If medication is needed, low-toxic, low-irritation, and mild disinfectants and insecticides can be selected under the guidance of professional technicians.