Water Quality Management in L Vannamei Shrimp Culture

Water quality management is the management of water quality parameters daily to keep it in optimal conditions for the growth of shrimp. This is very important to prevent the shrimp from experiencing stress that can accelerate the onset of various diseases.

Transparency and Water Color

These water quality parameters reflect the type and density of plankton. The core of this management is that each change can be followed and anticipated to avoid stress on the cultured shrimp. The more intense the colour of the water signifies the denser the number of existing plankton. Plankton density that is too high may affect fluctuations in dissolved oxygen and pH in the pond. On a sunny day, the amount of dissolved oxygen will be very high and the pH tends to lower, while in the evening, the pH will be very high and dissolved oxygen can decrease to less than 2 ppm. Transparency must be maintained at a level of 30-40 cm. If the density of plankton is very high, it must be reduced by replacing the water in the pond preparation.

pH (Hydrogen)

 In shrimp culture, we aim for the pond pH value to be equal or approximately equal to the pH value of the shrimp's body. This is intended to allow the shrimp to not experience stress in shrimp adjusting the pH of the body to its environment. pH in pond waters should be maintained in the range of 7.5-8.5. If the pH in pond waters is below the standardized range, it must be enhanced by the provision of lime.

DO (Dissolved Oxygen)

 Dissolved oxygen management is very important because DO is a key factor for the success of Littopenaeus vannamei shrimp culture. DO content in the morning should be above 4 ppm and above 6 ppm during the day. Managing the concentration of DO in pond waters is closely related to the amount and type of phytoplankton, the number and condition of existing aerators, shrimp biomass, total organic matter content in the pond, and bacterial activity. Dissolved oxygen concentrations below 4 ppm make shrimp have difficulty capturing oxygen, causing them to rise to the surface of the water to get oxygen. If this persists for a long time, the shrimp will suffocate. If the shrimp experience a shortage of dissolved oxygen, actions to take include performing the replacement of pond water, maximizing the use of aerators, and spreading lime to inhibit the process of respiration from organisms other than shrimp.

Salinity

Optimal salinity is required for shrimp to establish proper metabolic processes. If the salinity in the shrimp's body fluids is higher than that of the environment, water from the environment will enter the shrimp's body, causing cells to swell. Conversely, if the environmental salinity is higher than the shrimp's body fluids, water from the shrimp's body will come out, causing the shrimp to become thin. The optimal salinity for the growth of shrimp is 15-30 ppt.

Temperature

Water temperature greatly affects the condition of shrimp, especially their appetite. The higher the water temperature, the higher the metabolic processes in the body of the shrimp. Conversely, if the water temperature is very low, metabolic processes in the shrimp's body are inhibited, and the shrimp may not want to eat. The optimal temperature for the growth of shrimp is 28-30°C.

TAN (Total Ammonia Nitrogen)

TAN measurements are aimed at determining the ammonia content in Littopenaeus vannamei shrimp ponds as metabolic waste, dead plankton, organic matter input, and the remaining feed that is not biodegradable. Levels of Total Ammonia Nitrogen (TAN) in ponds should be no more than 2 ppm. If the TAN value is high, it means residual organic material in the pond is not decomposing well and should be immediately expelled.

Free Ammonia (NH3)

Ammonia is formed due to the decomposition of organic material that is not perfect. Residual feed and shrimp feces with high protein content can accumulate. If the protein does not decompose completely, the ammonia content in the pond becomes high. The standard level of ammonia in the pond should not be more than 0.01 ppm.

Alkalinity

Alkalinity is the amount of carbonate, bicarbonate, and hydroxide contained in the water. Alkalinity becomes an important key in the water because of its ability to sustain pH without lowering the pH value. The standard value in the alkalinity of pond waters is equal to or greater than 80 ppm. If the alkalinity of pond water has a value below the standard things to do is the application of lime, treat bacterial decomposition and the addition of CO2. 

Conclusion

Physical and chemical variables of water quality directly affect the growth of fish by influencing the rates of metabolism, reproduction, life cycles and health of fish.

Controlling water quality is one of the main guidelines for making Littopenaeus vannamei shrimp farming a profitable business