In the shrimp aquaculture process, shrimp disease generally occurs after the weather changes, especially after the rain. Therefore, how to prevent shrimp disease after rain is the main factor for the success of shrimp culture. The causes of post-rainbow shrimp disease and the types, symptoms, and prevention and control methods of shrimp diseases are briefly described below for your reference, and they hope to have a certain guiding role for the majority of shrimp farmers.

I. Causes of shrimp disease after rain

1. Water temperature Prawn is a kind of invertebrate with low temperature and it will cause changes in water temperature after the fresh water rushes into the aquaculture waters. It will inevitably lead to the decrease of digestive system and immune system function of shrimp. On the one hand, digestive tract secrete digestive enzymes to reduce, prawns do not eat, digestion : malabsorption, there may be the phenomenon of empty stomach, jejunum and liver deterioration; on the other hand shrimp immune function is reduced, disease resistance is poor, easy to disease.

2.pH After the rain, the pH value of the culture water is often reduced (because the rainwater is mostly acidic), and the algae in the water body are dying, sometimes the pH value will be reduced to about 7.3, but the shrimp can not adapt immediately and it is easy to develop.

3. After the dissolved oxygen storm, fresh water rushes into the aquaculture water, resulting in the exchange of upper and lower layers of the aquaculture water. The bottom water with low dissolved oxygen content is exchanged to the surface water, and the surface water with high dissolved oxygen content is exchanged to the bottom layer, which easily causes the dissolved oxygen content of the aquaculture water. Low and can not meet the needs of shrimp growth, but also easily lead to the incidence of shrimp.

4. The salinity of freshwater into the aquaculture water after rain often causes the change of the salinity of the aquaculture water to be too large, which has a great influence on the physiological function of the penaeid shrimp. The prawns are not adaptable and susceptible to the disease within a short time.

5. Ammonium nitrogen and nitrite Due to the low dissolved oxygen content in the aquaculture water after rain, the organic matter in the aquaculture water can not be oxidized and decomposed normally, resulting in more ammonia nitrogen, nitrite and other toxic substances, and ammonia Nitrogen and nitrite are more toxic, and when it exceeds the standard, it will also cause the disease.

Second, the type of shrimp disease after the rain

1. Soft-shell disease The disease often occurs 1 to 2 days after the rain. The diseased shrimp is reddish-brown, the shell is soft, and the stomach is empty. The liver is atrophic, depleted, and congested. The diseased shrimp swims slowly and omnidirectionally on the surface of the water. , it will die after the salvage. Every morning and evening, sick shrimp floats on the water surface, especially when the aerator is stopped. Most of the disease is caused by mutations in the water environment, plus the pathogens that cause shrimp shelling.

2. Vibriosis is caused by the proliferation of Vibrio and other pathogenic bacteria in aquaculture water after rain. Symptoms of sick shrimp are red, sometimes the swimming foot becomes red, the stomach is empty, the liver is swollen, the body is reddish, anorexia, and there is a small amount of death.

3. The exchange of water between the upper and lower water layers of the aquaculture water after the jaundice rain tends to muddy the mud at the bottom of the pond, the color of the water is close to yellow, and the crust of the prawn is clogged, causing the lumbosacral yellow. This situation is prone to occur in earthen ponds and can cause black shank if not treated in time.

4. The rain of the brown spot often leads to the clam shell of the shrimp. The large number of bacteria in the breeding water body can easily cause shrimp crustacean disease. The crustaceans and appendages have black ulcer spots, and the ulcer edge is white and the central depression.

5. Floating heads and pans are flushed into the aquaculture waters. In addition, the weather is sultry and windless, the aquaculture water body is in a long time of oxygen deprivation, shrimps float on the surface of the pool or the surface of the water, and even cause hypoxia.

6. The depletion occurred mostly in the middle and later stages of breeding, due to high stocking densities, continuous high temperatures, abrupt changes in water temperature, insufficient dissolved oxygen, aged water, dirty bottom, more bait and feces, and ammonia and nitrous acid in the pool water. High salt content caused. Most of the diseased shrimp that had consumed at the bottom of the disease died at the bottom of the pool, and a few died during the observation of the cage, and the amount of feed fed was significantly reduced.

Third, the prevention and treatment of shrimp disease after rain

Sprinkle lime water or sodium humate a few times to stabilize the pH of the aquaculture water. Chlorine dioxide is used twice to disinfect the body of water, and an appropriate amount of oxygenating agent can be applied before using the disinfectant. Oral combination of vitamin C, shrimp multidimensional, immune polysaccharides, and aquatic yeast, 2 times a day for 7 days. When the weather improves, a microbial preparation can be used to cultivate beneficial algae.

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