Hot weather makes aquaculture difficult

( Quang Ngai Newspaper) - Prolonged hot weather, high temperature and salinity cause farmed aquatic products, mainly brackish water shrimp and snails, to become infected or die from heat shock...

Efforts to "protect against the sun"

In recent days, brackish water shrimp and snail farmers in localities in the province have struggled to find ways to reduce the heat and at the same time strengthen measures to prevent and control aquatic diseases. In brackish water shrimp farming areas in Duc Minh and Duc Phong communes (Mo Duc), pond owners have been pumping out waste accumulated at the bottom of the ponds, continuously monitoring and handling changes in water levels and water quality, in order to limit the situation of shrimp suffering from heat shock.

Snail farmers in Pho Quang ward (Duc Pho town) have increased measures to care for their snails in hot weather conditions.

Mr. Bui Tan Quoc, in Duc Minh commune, said that the prolonged hot weather makes the water in the lake easily polluted, causing a lot of algae to grow, causing the shrimp to develop unevenly and become susceptible to disease. The most difficult thing is to calculate and measure the shrimp's food ration to ensure both quality and quantity, and not let excess food settle at the bottom of the lake, causing water pollution. I have reduced the food ration to 70% compared to normal and added vitamins and minerals. However, the prolonged hot weather has caused the shrimp to show signs of disease and slow growth.

Many pond owners in Zone 7, Pho Quang Ward (Duc Pho Town) are anxious because the snails are not eating well due to the hot weather. Most of the snails in this area have been released for 30-35 days, and are in the "nursing" period, so they are very sensitive to the environment. Therefore, in addition to controlling the food portion, pond owners must regularly pump water, especially in low ponds to ensure a minimum depth of 1.4m, to stabilize the temperature and salinity of the water in the pond. Mr. Nguyen Teo, in Pho Quang Ward, said that when the power source is not guaranteed, the pump works intermittently, leading to frequent interruptions in pumping water, especially during hot sunny days. Although additional water fans and regular aeration have been installed to provide enough oxygen, sometimes the temperature and salinity in the pond increase, making it easy for the snails to get sick or even die from heat shock.

The province currently has about 550 hectares of brackish water aquaculture, mainly shrimp and snails. To limit damage caused by prolonged heat, in addition to efforts to maintain the water level in the pond at least 1.4m or higher, many snail farmers have used nets to cover 2/3 of the pond surface area and are 2m above the water surface to limit solar radiation. In farming areas without a guaranteed power source, pond owners have purchased generators or temporarily stopped stocking. Meanwhile, some shrimp pond owners are harvesting to both reduce density and reduce care costs. According to Mr. Bui Tan Quoc, shrimp prices are currently very low, only 65 - 70 thousand VND/kg for shrimp of size 110 - 120 pieces/kg, while farming costs are high, facing many risks due to heat and disease. The gradual harvest will help farmers reduce some of the damage.

Recommendations from the relevant authorities

Deputy Head of the provincial Department of Fisheries Do Thi Thu Dong said that to help aquaculture farmers proactively respond and minimize damage caused by the heat, the department has coordinated with localities to propagate and recommend pond owners to implement "sun protection" measures associated with disease prevention in shrimp and snails, including periodic environmental monitoring. Thereby, promptly assessing the quality of water sources in brackish water shrimp and snail farming areas; advising and guiding pond owners on a number of appropriate treatment measures for each subject and the current status of water sources.

Mr. Huynh Den, in Pho Minh Ward (Duc Pho Town) shared, through the guidance of the provincial Department of Fisheries, I learned that my family's shrimp and snail ponds had 5/16 periodically monitored parameters exceeding the allowable limit from 1.6 - 9.1 times. For nearly 3 weeks, I have made efforts to implement remedial measures such as changing 50% of the pond water, regularly pumping water to ensure the water level in the pond reaches 1.4m or more; calculating appropriate food rations for shrimp and snails. Thanks to that, the shrimp and snails have now developed stably.

According to the forecast of the Provincial Hydrometeorological Station, from June to August, there will be widespread heat waves and severe heat waves, lasting for many consecutive days, with the highest temperature ranging from 37 - 39 degrees Celsius, in some places from 40 - 42 degrees Celsius. Therefore, the Provincial Department of Fisheries recommends that owners of brackish water shrimp and snail farms need to maintain appropriate stocking density and balance reasonable food rations corresponding to size, in order to stabilize water sources and bottom oxygen in the pond. Along with that, regularly check environmental factors to promptly detect unusual signs, especially in the early morning... "If you suspect or detect sick shrimp, farmers need to proactively report to the authorities as well as local veterinary agencies for timely support. Pond owners absolutely must not discharge wastewater containing sick shrimp or suspected sick shrimp that has not been treated according to veterinary instructions into the environment, causing the spread of disease," Ms. Dong advised.

Article and photos: MY HOA