Shrimp is a lower animal without specific immune system. Thus, its ability to resist pathogens is poor. There is currently no vaccine for disease prevention in shrimp. Weak shrimp is easily susceptible to virus (e.g., white spot, Taura syndrome) and bacteria (e.g., Vibrio). If shrimp has serious disease, farmers have to not only deal with reduced yield, even face lost, but also pay for the expensive cost of pond treatment.
Shrimp body temperature varies based on temperature of the surrounding water. When weather changes, shrimp is easily shocked, becomes weak and susceptible. When there is prolonged hot, sunny weather (water temperature above 32 degrees Celsius), white feces syndrome often appears. During cold weather (water temperature below 25 degrees Celsius), shrimp catches prey weakly, even stops eating; white spot syndrome can occur. It is an urgent for preventing diseases in shrimp, especially when there are weather changes.
Some signals of shrimp infected by diseases are its lethargic swimming on the water surface or near pond banks, shores, feeding trays. Shrimp reduces eating, may die at the pond bottom. Meanwhile, healthy shrimp will live with infected and dead shrimp. Healthy shrimp can eat dead shrimp, making the disease become more widespread. When shrimp is infected by diseases, it often stops eating. Medicined mixed into feed will not get into shrimp body; thus, treatment is ineffective. Therefore, the earlier diseases in shrimp can be detected, the higher chance it will be cured.
When shrimp is infected, farmers often urgently harvest while still using medicines and chemicals for shrimp. This affects the quality of shrimp. Thus, disease prevention is important and necessary to do. Avoid waiting for shrimp to be infected to cure later.
If shrimp is infected by diseases, following treatments should be proceeded simultaneously:
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In rainy season
In the shrimp ponds
Temporary process for safe brackish-water shrimp farming in areas affected by diseases in Vietnam