Mekong Delta: Shrimp farmers wait for... salt water

SGGP 27/02/2023 06:30

The beginning of the dry season is the time when farmers release shrimp larvae to start a new farming season, but due to lack of salt water, many localities in the Mekong Delta have released shrimp larvae more than a month later than scheduled.

Farmers in Vinh Thuan district ( Kien Giang ) check water quality in shrimp ponds. Photo: QUOC BINH

After the historic drought and salinity in 2016, Kien Giang province converted about 110,000 hectares of rice cultivation area to shrimp-rice rotation to adapt, concentrated in the U Minh Thuong region (including An Bien, An Minh, Vinh Thuan, U Minh Thuong districts) and part of the area of ​​Go Quao district.

According to the production practices of farmers in the U Minh Thuong region, after harvesting rice on shrimp land, after Tet, farmers began to renovate square ponds and release shrimp larvae, but due to unseasonal rains, the salinity in the canals in the fields was only 1-2‰, so the release of shrimp larvae was late in the season.

In Bac Lieu and Soc Trang provinces, farmers also released shrimp larvae late. Currently, only about 30%-50% of shrimp farming areas are stocked with larvae. Most farmers have to treat the water again after pumping it into the pond.

Ms. Quach Thi Thanh Binh, Head of the Department of Fisheries of Soc Trang province, said: “Up to now, the whole province has only reached about 50% of the shrimp farming area compared to the same period (mainly whiteleg shrimp). The main reason is that the shrimp crop at the end of 2022 has many diseases, people only release in moderation to cut off the pathogens left over from the previous crop. Besides, part of the reason is due to unusual weather developments that make people cautious.”

Farmers are currently eager to release shrimp larvae but are still worried that the salinity has not yet met the requirements. Not only is the salinity low, but compared to the same period in 2022, this year the saltwater intrusion into the fields is also 15-20 days later. Currently, the salinity measured at the Cai Lon River mouth is approximately 3‰, an increase of 1‰ compared to 10 days ago, 7.1‰ lower than the same period; in the inland canals, the salinity measured is 1-2‰.

Farmer Nguyen Van Ngoi (Hoa Chanh commune, U Minh Thuong district, Kien Giang province) said that to release shrimp fry, he had to wait for the salinity to rise to about 5-7‰ to pump into the pond, but he waited forever and still did not see any salinity, the salinity of the water in the canal was only 1-2‰, so many households in the commune took the risk of pumping water in and treating it, then waiting for the tide to rise, the salinity would be higher and they would continue to pump more.

“The timing of releasing shrimp fry depends on the annual weather and hydrological conditions, and the sales contracts signed with traders and businesses. If we release shrimp fry late, it will lead to a delay in the contract. At best, we will lose our reputation, and at worst, we will have to pay compensation,” Mr. Ngoi worried.

Meanwhile, in areas near the estuary, farmers apply the improved extensive farming model, raising 3-4 shrimp crops per year, so the need for salt water is more urgent. With this model, after harvesting, the ponds will have to be exposed to the sun and then wait for the water from the river or canal to be salty enough before pumping it into the pond. According to many farmers, whiteleg shrimp need high salinity, so to be effective and limit loss, they must wait for the water to be salty enough before releasing the shrimp.

According to the Meteorological and Hydrological Station of Kien Giang province, the reason for the late arrival of saltwater in 2023 and low salinity is due to the increase in upstream flow to the Mekong Delta through the two stations of Tan Chau and Chau Doc (27% higher than the same period in 2022, 7% higher than the average of many years). On the other hand, relatively heavy unseasonal rains in the areas of Go Quao and Giong Rieng districts caused the salinity on Cai Lon and Cai Be rivers to decrease sharply. By the first half of February 2023, salinity was still low, and saltwater had not penetrated deep into the fields.

According to the Southern Hydrometeorological Station, in March there will be periods of sudden increase in salinity due to the impact of rising sea levels and reduced discharge from upstream hydropower plants. Saline water will begin to penetrate deep into the fields at this time, farmers can take advantage of the high tide to bring water into their ponds. Therefore, localities need to regularly monitor the forecast of salinity and promptly notify people to be proactive in production.

The Department of Agriculture and Rural Development of Kien Giang province has proposed that the management unit of the Cai Be - Cai Lon irrigation sluice system (Kien Giang province) operate in accordance with the shrimp - rice model of the U Minh Thuong region. For the system of 17 sluices along the An Bien and An Minh sea dykes, the People's Committee of Kien Giang province has directed departments and branches to coordinate with the Provincial Management Board of Investment Projects for Construction of Agricultural Works and Rural Development to urgently invest in a power grid system to serve the sluice operation and serve the people's shrimp - rice production.

Source: https://www.sggp.org.vn/dbscl-nong-dan-nuoi-tom-ngong-nuoc-man-post680155.html