Environmental management of shrimp farming in hot season

Prolonged hot weather has caused damage to shrimp farming areas in many localities. To have an effective shrimp farming season, farmers need to pay attention to limiting changes in environmental factors in shrimp ponds.

Hot weather makes the farming environment susceptible to sudden changes, especially pH and temperature, which greatly affects the growth of farmed shrimp. Hot weather causes the water in the shrimp pond to evaporate quickly, thereby increasing the temperature and salinity, affecting the growth of farmed shrimp. Aquatic plants in the pond die and decompose quickly, causing changes in water clarity. Water in dry ponds is also the cause of changes in pH of the farming environment. Moreover, in the dry season, there is often unseasonal rain, causing the water environment to fluctuate (pH decreases, temperature changes suddenly), shrimp lose their resistance, are susceptible to disease, or die from heat shock.

Farmers need to monitor environmental factors regularly to know the developments, thereby having technical impacts to create a favorable environment, suitable for the development of farmed shrimp.

The suitable temperature for the pond ranges from 20 - 300C. To overcome the situation of high temperature and salinity, it is necessary to actively maintain the water level in the pond at 1.2 - 1.5 m. When water leaks and evaporates, causing the water level to decrease or when the water in the pond is dark in color, it is necessary to slowly add water, about 20 - 30% of the water in the pond, add it in cool weather, through a treated settling pond. When adding more water, it is necessary to combine the use of agricultural lime (CaCO3) from 10 - 15 kg/1,000 m3 of water, fertilize when it is dark (21 - 22 o'clock) and can be repeated 2 - 3 times until the environmental factors in the pond return to the appropriate threshold.

Photo: Quoc Minh

Maintain pH within the appropriate range (7.5 - 8.5). If pH is lower or higher, change the water and apply Dolomite lime or agricultural lime at a rate of 150 - 300 kg/ha. Periodically apply agricultural lime every 7 - 10 days in the evening at a rate of 10 - 15 kg/1,000 m3 to stabilize pH and alkalinity in the pond, creating conditions for shrimp to molt.

When there are signs of rain, farmers need to prepare lime, spread around the pond bank with a dosage of 10 - 15 kg/100 m2, limit alum from washing into the pond, after the rain, it is necessary to check environmental factors to make appropriate adjustments.

According to (Vietnam Fisheries) - LC