Kien Giang: Shrimp farmers adapt to drought and salinity
With prolonged heat waves and saltwater intrusion predicted to exceed historical averages, shrimp farmers in Kien Giang province are taking proactive steps to minimize the risks posed by drought and salinity.
According to the Kien Giang Hydrometeorological Station, saltwater intrusion is expected to occur from February to April 2025 at levels higher than the multi-year average. The highest salinity concentrations in the Cai Lon and Cai Be rivers are projected to appear in late March and April. The U Minh Thuong region, including An Minh, An Bien, U Minh Thuong, and Vinh Thuan, has been particularly vulnerable to drought and salinity-related damage in recent years.
Farmers’ adaptive strategies
Shrimp farmers note that black tiger shrimp and white-leg shrimp thrive in salinity levels of 5-20‰, while mud crabs can tolerate a range of 10-25‰. The ideal water temperature for these species is between 25-32°C. To mitigate the impact of high salinity during hot weather, farmers in U Minh Thuong have been dredging pond beds and embankment canals before the main shrimp season. This practice helps reduce organic matter accumulation, preventing the formation of toxic gases in high temperatures.
Bui Van Trung, a farmer from Chin Xang Hamlet, Dong Hoa Commune (An Minh), shared: “After harvesting my seasonal rice crop, I dredge the pond bed to prevent organic waste buildup, which can generate toxic gases under intense heat, affecting shrimp health. Throughout the farming process, I use zeolite and probiotics to maintain water quality and keep the pond bottom clean.”
Nguyen Thanh Tung, a farmer in Chin A Hamlet, Thuan Hoa Commune (An Minh), explained, “Before filling my ponds, I always measure the salinity of the canal water to avoid taking in excessively salty water, which can limit natural food sources, slow shrimp growth, and increase disease risks.” During hot periods, he maintains water levels between 60-70 cm to reduce temperature fluctuations between day and night, which can stress shrimp. He also selects high-quality water sources for replenishment.
For Nguyen Thanh Tuan, a farmer in Ba Bien B Hamlet, Nam Yen Commune (An Bien), elevated pH levels during hot weather require regular water exchanges and the use of disinfectants to prevent disease outbreaks. During heavy rains, he applies dolomite lime around three meters from the pond’s edge to stabilize pH levels and adds mineral supplements to strengthen shrimp and crab immunity.
Infrastructure enhancements for drought and salinity prevention
To protect agricultural production, the districts of An Minh and An Bien have built and reinforced 29 temporary earthen dams to block saltwater intrusion. These measures help safeguard winter-spring rice crops for the 2024-2025 season and ensure a reliable water supply for local residents.
During peak dry-season conditions, shrimp farmers make use of periods of lower salinity to fill their ponds. Tran Van Quan, a farmer in Kinh 1A Hamlet, Dong Thai Commune (An Bien), stated: “To minimize the impact of rising salinity, I fill my ponds when the salinity level is around 5‰. During the farming cycle, I only add small amounts of water, which slows down salinity increases compared to canal and ditch water. To improve shrimp and crab survival rates, I use a two-stage nursery system for black tiger shrimp, releasing them into larger ponds only after they reach a size of 10,000 shrimp per kilogram. I also wait until crabs grow to the size of a pinky fingertip before transferring them to the main pond.”
In some coastal communes of An Bien and An Minh districts, many farmers prefer mud crab farming over black tiger and white-leg shrimp due to crabs’ higher tolerance for salinity and stronger market demand, particularly for roe-bearing crabs.
VFM
