Note on brackish water shrimp farming in hot season

The prolonged hot weather and the forecast of rising temperatures in the coming time may adversely affect the health of aquaculture products, especially brackish water shrimp. Therefore, farmers need to implement effective shrimp pond management measures.

Environmentally sensitive

According to the Department of Fisheries of Tien Giang province, the prolonged hot weather in recent days has caused the brackish water shrimp pond environment to change suddenly, especially the pH and water temperature factors; This has caused the shrimp to be shocked by the environment, become weak and easily break out with diseases. The hot weather also causes the water in the shrimp pond to evaporate quickly, the salinity in the pond also increases, making the shrimp susceptible to hepatopancreatic necrosis disease.

In addition, the hot weather and high salinity cause aquatic plants in shrimp ponds to die and decompose quickly, which is a source of nutrients for algae to grow strongly, leading to changes in the clarity of the water in the pond. Algae appearing with high density is also the cause of the phenomenon of shrimp floating their heads in the morning due to lack of oxygen, if severe, they will die en masse. Water in shallow ponds is also the cause of changes in pH of the farming environment. For areas with a lot of alum, the pH will drop due to alum from the soil of the bottom and the dike leaking into the shrimp pond.

Environmental factors in shrimp ponds change more suddenly when there are off-season rains or early season rains with large water flows. At that time, rainwater will wash away alum from the pond bank into the shrimp pond, causing the pH to drop, the temperature to stratify, leading to the phenomenon of weak shrimp suddenly dying, losing resistance and becoming susceptible to disease.

Comply with shrimp pond management rules

In shrimp farming, good management of water environment factors in the pond is very important. If the temperature, salinity, pH, alkalinity, dissolved oxygen... are kept stable within appropriate thresholds, the shrimp will grow well. Therefore, it is necessary to regularly check environmental factors and monitor shrimp activities.

Farmers need to build their own settling ponds, take the initiative in water sources and treat water before taking it into the pond to create the most favorable environmental factors for shrimp growth as well as limit pathogens from outside. At the same time, it is necessary to proactively maintain the water level in the pond (over 1.2 m) to limit the adverse effects of hot weather. Regularly check and reinforce the dykes after each crop to avoid water leakage from the outside or from one pond to another. If the water in the shrimp pond is dark in color and has a high pH, ​​it is necessary to immediately change 20% of the water or add more water to the pond through the settling pond.

During the hot season, sometimes unseasonal rains occur, causing fluctuations in the water environment. It is necessary to monitor and manage the ponds to prevent shrimp from being shocked and affecting their life activities. When there are signs of rain, lime should be spread around the shrimp pond at a dosage of 10 - 15 kg/100 m2 to limit the alum from washing into the pond.

In addition, hot weather often causes high salinity, low transparency, algae growth, large pH fluctuations during the day, low oxygen at night... leading to slow growth of shrimp, red body due to lack of oxygen... If possible, water should be supplied to compensate for the amount of evaporated water. Water should be supplied slowly, about 20 - 30% of the water in the pond, supplied in cool weather, around 7pm, water needs to be supplied through settling ponds and treated. Biological products should be used periodically to help stabilize the environment and limit toxic gases in the pond.

After the rains, farmers must check the environmental factors in the farm to take timely remedial measures, drain the surface water, or use fans or motorboats to move around the farm to break the stratification of water temperature. In addition, shrimp should be stocked at a moderate density for easy management. During the farming process, a diary should also be kept to monitor daily activities to facilitate the management of shrimp health, as well as to serve the traceability of products.

According to Thuysanvn