Thursday, August 12, 2010

Water Quality Management in Shrimp Culture

Water quality management is basically the management of water quality parameters daily to keep it in optimal conditions for growth of shrimp. This is very important to prevent the shrimp experience stress that can accelerate the shrimp to various diseases.
Water quality parameters that must be managed well are: (1) transparency and water color, pH, DO, salinity, temperature, TAN (total ammonia nitrogen), free ammonia (NH3), and alkalinity.
Transparency and Water Color
These water quality parameters reflecting the type and density of plankton. Core of this management is that each change can be followed and is anticipated to avoid stress on the cultured shrimp. The more intense the color of water signifies the more dense the number of existing plankton. Plankton density 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 the evening will be very high pH 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 pond.
pH (Potential Hydrogen)
In shrimp culture we want for pond pH value is equal or approximately equal to the pH value of the shrimp body. This is intended to allow the shrimp do not experience stress in adjusting 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 are under the range of standardized, it must be enhanced by the provision of lime.
DO (Dissolved Oxygen)
DO manage to be very important because the DO is a key factor for the success of shrimp culture. DO content in the morning should be above 4 ppm and above 6 ppm during the day. Manage the concentration of DO in pond waters are very closely related to the amount and type of phytoplankton, the number and condition of the existing aerator, shrimp biomass, total organic matter content in the pond, and bacterial activity. Dissolved oxygen concentrations below 4 ppm make shrimp difficulty capturing oxygen, so the shrimp will rise to the surface of the water to get oxygen. If this goes on for a long time, the shrimp will suffocate. If the shrimp shortage of dissolved oxygen, things to do is to perform the replacement of pond water, maximize the use of the aerator, and spread lime to inhibit the process of respiration from organisms other than shrimp.
Optimal salinity is required for shrimp to establish the metabolic processes properly. If the salinity in the shrimp body fluids is higher than the environment, the water in the environment will enter into the shrimp body so that the cell will swell. On the contrary, if the environmental salinity is higher than the salinity of shrimp body fluids, the water in the shrimp body will come out so that the shrimp become thin. Optimal salinity for growth of shrimp is 15-30 ppt.
Water temperature greatly affects the condition of shrimp, especially appetite. The higher the water temperature will be higher the metabolic processes in the body of the shrimp. Conversely, if the water temperature is very low metabolic processes in the body of the shrimp is inhibited so the shrimp do not want to eat. The optimal temperature for growth of shrimp is 28-30 oC
TAN (Total Ammonia Nitrogen)
TAN measurements aimed to determine the ammonia content in the shrimp ponds as metabolic waste, dead plankton, organic matter input and the rest of the feed that is not biodegradable. Levels of Total Ammonia Nitrogen (TAN) in pond should be no more than 2 ppm. If the value of TAN is high its mean residual organic material in the pond does not decompose well and should be immediately expelled.
Free Ammonia (NH3)
Ammonia is formed due to decomposition of organic material that is not perfect. Residual feed and shrimp feces will accumulate with high protein content. If the protein does not decompose completely the ammonia content in the pond becomes high. A standard level of ammonia in the pond is not more than 0.01 ppm.
Alkalinity is the amount of carbonate, bicarbonate, and hydroxide contained in the water. Alkalinity become an important key in the water because of its ability to sustain the pH, because the addition of acid without lowering the pH value. 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 thing to do is the application of lime, treat bacterial decomposition, and the addition of CO2.

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