It is necessary to prevent the death of river crabs in autumn

Autumn is not only the season of ripeness and harvest of river crabs, but also the peak period of death of river crabs. Therefore, strengthening the management of river crab culture in autumn is the key to prevent the death of river crab in autumn and improve the efficiency of river crab culture.

To prevent natural death as the saying goes, "when the west wind blows, the crab's feet itch." From September to November every year, a group of river crabs that have grown for 2 years have shelled and become green crabs, and their gonads mature and enter the final stage of their life. All the river crabs whose feet itch to escape, because they have matured and the osmotic pressure in the body is increased, can not adapt to the freshwater low osmotic pressure environment, which leads to the natural death of most river crabs. Therefore, these river crabs should be caught and sold in time.

To prevent cold death in autumn, the temperature varies greatly during the day and night, and the water temperature varies greatly, sometimes as high as 10 ℃. The river crab dies because it does not adapt to this environmental condition. Therefore, it must be prevented. Prevention methods: first, we should pay attention to adjust the water level at ordinary times, control the sharp change of water temperature, and the temperature difference between the injected new water and the old water should not be more than 3 ℃. Second, the surface of the water should retain more water hyacinth, water peanuts and other mulch, but not larger than the surface of the 1max 2. Third, when the weather changes, the water level should be deepened.

Prevent the death of indigestion in autumn due to drastic changes in air pressure and water temperature, leading to changes in the eating habits of river crabs, easy to cause indigestion of river crabs, and even lead to the death of all river crabs. Therefore, must be serious prevention and control, methods: first, improve water quality, regularly disinfect with lime water. Second, antibiotics and auxins are added regularly to the feed. Third, do not feed or less plant feed, and increase animal feed, especially high-protein feed such as earthworms and snails. Fourth, the feeding should be fixed and quantitative, and the amount of feeding should be reduced appropriately when the water temperature drops.