* This article is made based on content published by Nanang Ardianto via LinkedIn on this link https://www.linkedin.com/posts/nanang-ardianto-_na-nanyaaja-nanangardianto-activity-6710893832302682112-Sjyt/ *
Rain is a natural phenomenon that cannot be avoided. Though various technologies are available to get to know more about the phenomenon, we are still unable to accurately predict when, where, and how the heavy precipitation of rain will happen. One of the activities that are greatly influenced by the natural condition of the environment is the outdoor cultivation of shrimp farming.
Torrential rainfall certainly affects the quality of pond water, which indirectly also affects the resulting quality of shrimp cultivation that is being done. Poor pond water quality can lead to problems such as illness and the death of shrimp. The phenomenon of rain that occurs in the evening also will affect the passage of pond water ecosystems, if the need for minerals is not fulfilled.
What happens in the shrimp pond when there is rainfall?
- The pH of the water will increase the next day, because of the acidic nature of rainwater.
- Water salinity will drop the next day because rainwater comes from the vaporized brackish water.
- Decreasing level of dissolved oxygen (DO) in water.
- The amount of plankton is reduced because of the erosion by the rainwater compound that is different from the pond water.
- Shrimp experiences stress due to changes in the condition of the environment around them, which triggers the occurrence of mass moulting.
After rainfall happens, sediment derived from the particles and organic material brought by the rain often is formed in the base of the pool. Particles and organic materials often contain pathogens that can evolve into a seedling disease for shrimp. A strong wind that happens as the rain is falling causes a surge of water in the pond that stirs the sludge and pushes it to the surface, making pond water looks muddy.
From all the things above, it can be seen that heavy rainfall can disturb the shrimp cultivation activity and threaten shrimp survival. Shrimp will experience stress due to the sudden changes in their environment that lead to high shrimp mortality rate. Feed consumption will also decrease and shrimp would be more susceptible to infection.
During rainfall, shrimp will tend to go down to the base of the pool to look for a much warmer temperature. It results in the gathering of shrimp in such small spaces where shrimp will each compete for oxygen. The gathering of shrimp in the base of the pool also makes shrimp more easily exposed to toxic substances such as H2S that is released by the deposition of mud and organic materials.
What can be done to minimize the effect of heavy rainfalls?
- Adding minerals in the morning to add nutrients for planktons and shrimps.
- New water circulation to restore the pond ecosystem.
- Slowing the feeding process if shrimp experiences a sudden loss of appetite.
- The addition of an aerator to increase dissolved oxygen (DO) levels after it falls due to rainfalls.
Another thing that is also important to note is that farmers keep the level of oxygen 20% higher than the normal level and ensure that rainwater deposited in the surface of the pond can flow out to not excessing the surface and contaminating pond water.