Shrimp Farm Water Quality Management
Managing water quality is of utmost importance in shrimp farming operations. Good water quality ensures proper growth of shrimp and reduces mortality. Various water quality parameters such as salinity, hardness, temperature, dissolved oxygen levels, nitrite levels among others need to be adhered to for ensuring optimum production. It may be sound complicated however it is pretty easy to monitor these parameters using easily available test strips.
The optimum dissolved oxygen content of pond waters is about of 5 mgllitre. Aeration is a proven technique for improving dissolved oxygen availability in ponds. Various types of aerators are used for pond aeration. In heavily aerated ponds strong water currents can cause erosion of pond bottom. Therefore, placement of aerators in a pond should be considered carefully.
Often people include plants in the pond to keep the pond well-oxygenated. It should however be kept in mind that though they may release large amount of oxygen but in night they tend to taken all the oxygen which may cause fluctuation in oxygen levels. In warm weather the problem may get worse as warm water generally tends to have less oxygen.
The following steps help to alleviate the problem:
– Enhancing water circulation by using aerators.
– Reducing the stocking level.
– Removing the silt from the bottom of the pond as the bacteria that grow there consume a lot of oxygen thereby depleting dissolved oxygen levels so necessary for the shrimp population to thrive.
Temperature determines the rate of shrimp growth. Water temperature can be adjusted to optimum levels in indoor shrimp hatcheries. It is difficult to adjust water temperature in large water-bodies. Aerators not only help in improving oxygen levels but also help in maintaining uniform temperature.
Turbidity results from several factors including suspended soil particles, planktonic organisms and through decomposition of organic matter. Turbidity resulting from plankton is generally desirable. However, excessive turbidity prevent heat and light penetration adversely affecting shrimp growth.
pH is a measure of hydrogen ion concentration in water and indicates how acidic or alkaline is the water. The pH of water affects the metabolism and physiological processes of shrimps. pH also exerts considerable influence on toxicity of ammonia and hydrogen-sulphide as well as solubility of nutrients.
Hardness is an important factor for fresh water fish ponds. It should be ideally be greater than 40 mgllitre. Hardness helps to protect shrimps against harmful effects of pH fluctuation and metal ions. Ponds with relatively low hardness can be treated with lime to increase hardness.