Aquaculture encounters cyanobacteria outbreak, how to deal with it correctly?

In recent years, the outbreak of cyanobacteria in aquaculture in Guangxi is becoming more and more common, especially at the mouth of freshwater aquaculture ponds, which not only has a high frequency, but also occurs earlier and earlier. Cyanobacteria often broke out soon after release, seriously endangering the healthy growth of fish and shrimp seedlings.

Image source http://www.gxjljh.com/

The main causes of cyanobacteria outbreaks:

Eutrophication of water body, coupled with external conditions, suitable light and temperature will lead to large-scale outbreak of cyanobacteria; high nitrogen and phosphorus nutrients in water body will lead to the influx of rain sewage and domestic sewage; the PH value of water body is too high. It is also conducive to the growth and reproduction of cyanobacteria.

The dangers of cyanobacteria outbreaks:

In hot and bright weather, cyanobacteria gather on the surface of the water body to absorb most of the sunlight, multiply in large numbers and inhibit the growth of other algae. At the same time, in the process of reproduction, cyanobacteria will constantly secrete toxic metabolites into the water, causing the death of a large number of zooplankton, but cyanobacteria particles are difficult to be digested by fish and shrimp. At the same time, the death and decomposition of cyanobacteria will also consume a lot of dissolved oxygen and release a lot of toxic substances such as hydroxylamine and hydrogen sulfide. Under the condition of serious hypoxia and the existence of toxic substances, it will cause difficulties in survival and death of a large number of fish and shrimp.

Because many farmers do not understand the habits and causes of cyanobacteria, they just blindly follow the methods of others. The effect is not ideal, even kill cyanobacteria, but at the same time kill beneficial algae, indirectly kill fish and shrimp, resulting in serious culture losses.

Image source http://www.gxjljh.com/

Therefore, we should use scientific methods to deal with cyanobacteria:

1. Drainage: remove 30 cm ~ 40 cm surface water, cyanobacteria like light, and gather in the surface water at noon when the sun is high. Drainage can effectively reduce the number of cyanobacteria in the pool water.

2. Scientific stocking: according to pond conditions and management level, reasonable stocking, it is best to release some filter-feeding fish at the same time, and cultivate beneficial algae.

3. Fresh water should be injected frequently in the middle and later stages of culture. Activate the vitality of the pond water, often open the aerator to ensure a good amount of dissolved oxygen in the water.

4. Regular use of biological agents to regulate water quality. Detoxification, water regulation and biological oxygen enhancement are used alternately to improve the bottom environment.

5. For fish ponds where cyanobacteria have occurred, they must be thoroughly disinfected and cyanobacteria spores killed.

Image source http://www.gxjljh.com/

Specific measures:

In the case of strong green water quality, blue algae outbreak and abnormal water color, the use of special chlorine dioxide effervescent tablets for aquaculture can quickly destroy the chlorophyll of algae, kill algae, and have the effect of purifying and refreshing water. And the side effect is very small, and the safety factor is more than 10 times higher than the traditional algicides such as copper sulfate and erythromycin in aquaculture disinfection. Moreover, special chlorine dioxide for aquaculture can react with ammonia, sulfide and organic matter in water to improve water quality, such as decontamination, deodorization, deodorization, toxin degradation, flocculation and precipitation, and prevent cyanobacteria from happening again.

Article source http://www.gxjljh.com/