Minerals are inorganic substances essential for shrimp growth. They play a vital role in various physiological processes in shrimp, so shrimp farmers should pay extra attention to their sufficiency in their ponds.
Throughout their growth, shrimp absorb minerals from both their feed and the aquatic environment. The minerals include calcium, magnesium, sodium, potassium, iron, and copper. Among the various minerals required by shrimp, calcium (Ca) and magnesium (Mg) are two of the essential ones for shrimp.
Calcium and magnesium play a crucial role in improving shrimp production as they can accelerate the formation of exoskeletons in shrimp during molting. The faster the exoskeleton forms, the lower the risk of cannibalistic behavior in shrimp, thus increasing the survival rate (SR). Shrimp will also become more active in finding food after molting.
Additionally, calcium can minimize increases in pH that may occur during high photosynthesis rates by precipitating carbonate ions, forming calcium carbonate. This reaction reduces the amount of carbonate in the water available for hydrolysis, thus stabilizing the pH.
Calcium and magnesium ions can also neutralize the negative charges on suspended clay particles in water, causing them to form larger aggregates. As a result, water turbidity can be reduced.
Water naturally contains the minerals required by shrimp. However, the availability of minerals in shrimp farms may decrease due to soil adsorption, assimilation by the shrimp, and water replacement. Aside from affecting metabolism, the lack of minerals also disrupts phytoplankton balance, which impacts the whole farm ecosystem. This may lead to stress in shrimp, which causes softer shells and may lead to mortality. Hence, it is crucial to evaluate mineral concentrations in pond waters regularly and to give the proper treatment in case of any deficiency.
In shrimp cultivation, calcium and magnesium concentrations are rarely measured directly, but through a parameter known as total hardness. Hardness is defined as the concentration of divalent cations, which are mostly calcium and magnesium, in water expressed in mg/L (ppm) of equivalent calcium carbonate (CaCO3)
Since water hardness reflects the concentration of calcium and magnesium in pond water, and its value may decrease throughout cultivation, farmers are advised to do regular laboratory checking. This helps ensure the total hardness of their shrimp cultivation is at an ideal level, which is below 300 ppm.
Mineral dapat diserap oleh udang melalui pakan maupun air tambak. Perlakuan melalui air lebih disarankan karena lebih efektif dibandingkan dengan strategi modifikasi pakan. Pasalnya, larutnya mineral pada pakan ke dalam air menjadi halangan dalam pendekatan melalui pakan.
Perlakuan air untuk meningkatkan ketersediaan mineral dapat mulai dilakukan pada pertengahan budidaya atau DOC 30-60. Adapun perlakuan yang dapat dilakukan di antaranya:
CaCO3, calcium carbonate, or limestone is administered in water to increase pH, hardness, and alkalinity. Limestone is made up of calcium that can bind to H ions in water to increase pH and stabilize it.
Dolomite contains high levels of calcium and magnesium. Regular treatments with dolomite every 4-7 days with a dosage of 1-2 ppm can boost plankton growth and maintain pond water stability.
Quicklime or CaO has been widely used to adjust pH, supply beneficial minerals for shrimp, and support the molting process. However, due to its relatively extreme effect on pH, the dosage should be carefully considered to avoid any negative effects on shrimp.
Make sure to administer the above treatments only after evaluating the current pond conditions by monitoring water hardness and molting frequency. The dosage given should also be adjusted according to the total pond water volume to prevent adverse effects on shrimp.
At the same time, farmers should ensure that the feed given to their shrimp also contains various minerals required for their growth and health and a balanced nutritional profile. Moreover, implementing good environmental management practices by adhering to biosecurity principles can also help maintain mineral balance in shrimp farms. Good quality water, proper waste treatment and disposal, and appropriate salinity regulation will maintain water quality and mineral availability for more productive and sustainable cultivation.
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