Shrimp farming goes towards sustainability

According to the plan, in 2021, Binh Dinh will release shrimp on an area of about 2,107 hectares of ponds and lakes; of which, Tuy Phuoc district alone accounts for half of the above shrimp farming area. In recent years, in Binh Dinh, there have been "absences" of large floods, so the environment of shrimp farming areas here has not been washed away by floodwaters and has become polluted. More worryingly, most shrimp farmers in Binh Dinh raise shrimp using semi-intensive farming methods, the amount of wastewater discharged into the environment from shrimp farming is very large, making the environment of farming water areas even more seriously polluted.

Faced with this reality, the Binh Dinh agricultural sector has stepped up propaganda work so that local shrimp farmers comply with the crop schedule, stock at a reasonable density, intercrop shrimp with various types of fish and crabs, and especially ensure the safety of the farming water area to limit the occurrence of diseases in farmed shrimp.

“In shrimp farming, the environment of the farming water area is the most important. Especially in the past few years, there have been no major floods in Binh Dinh, so pollution from the backlog of farming crops year after year due to not being washed away by floods has caused the farming water environment to become increasingly polluted. While the shrimp farming method of local farmers is mostly semi-intensive, the amount of waste discharged into the environment is very large, causing diseases in farmed shrimp, causing farmers to suffer losses. In recent years, people's awareness of protecting the environment of farming water areas has been raised, thanks to which diseases rarely occur in farmed shrimp. For example, in 2021, from the beginning of the year until now, only 1.5 hectares of shrimp ponds in Phuoc Thuan commune have been affected by environmental diseases, other farming areas have not seen any outbreaks of disease," said Mr. Pham Quang An, Deputy Head of the Department of Agriculture and Rural Development of Tuy Phuoc district.

According to Mr. An, in recent years, shrimp farmers in Tuy Phuoc district have strictly followed the crop calendar issued by the provincial Department of Agriculture and Rural Development, which is also one of the factors that limit diseases in farmed shrimp. In addition, more and more shrimp farmers have realized that stocking at high density not only does not bring efficiency, but also causes diseases in farmed shrimp. Therefore, shrimp farmers here only stock at a reasonable density of about 30-40 shrimp/m2 according to the instructions of the functional sector.

"In particular, the improved extensive shrimp farming method intercropped with crabs and other species has made the farmers' income more sustainable. Previously, shrimp farmers in Tuy Phuoc district mostly raised only one shrimp, so when an epidemic occurred, they lost everything. Now, shrimp are intercropped with crabs and fish; This farming method has not only limited the epidemic, if the farmed shrimp are infected with the epidemic, the farmers still have income from crabs and fish, this is a condition for the next crop to continue investing in farming", Mr. An said.

According to Mr. Pham Thanh Nhan, Head of the Aquaculture Department of Binh Dinh Fisheries Sub-Department, in the first farming season of 2021, the farming areas in lagoons and estuaries had poor infrastructure, so before releasing the seeds, farmers had to reinforce, dredge, and clean and renovate ponds and lakes. Along with strengthening the management of farming areas, providing technical guidance, and propagating to shrimp farmers to comply with the seasonal schedule, Binh Dinh Fisheries Sub-Department also conducted monitoring and checking of temperature, pH, salinity, alkalinity, etc. parameters in farming areas to help people control and prevent shrimp diseases in the new farming season.

Settling ponds, the savior of shrimp farming areas

The low-tide area of Dong Dien village (Phuoc Thang commune) is currently a key biosafety shrimp farming area in Tuy Phuoc district (Binh Dinh). Previously, shrimp farmers in Dong Dien only raised black tiger shrimp with crabs and fish in the method of "releasing the seeds and leaving them to the sky" and then doing other jobs to earn income. When the shrimp grew big, they gathered to throw nets to harvest everything. Due to lack of care, the shrimp yield was very poor, only about 1.5 tons/ha. By 2013, the entire Dong Dien shrimp farming area abandoned black tiger shrimp and switched to raising white-leg shrimp, increasing the shrimp yield to 2 tons/ha.

"Thanks to the fact that the water source was not polluted at that time, the pond bottoms were still clean, so shrimp farmers here often reaped success. At that time, I raised shrimp on 4,500m2 of water surface area. Although I did not make much profit, I still earned 40-50 million VND in profit every year with 2 farming crops. When shrimp farmers increased the farming density from 20 shrimp/m2 to 50 shrimp/m2, while the farming water was not technically treated, only a few years later the farming area began to be polluted. That was also the time when shrimp in Dong Dien started to develop hepatopancreatic disease, and shrimp farmers here began to suffer losses," said Mr. Pham Van Chay, a shrimp farmer in Dong Dien.

According to Mr. Pham Quang An, Deputy Head of the Department of Agriculture and Rural Development of Tuy Phuoc District, in 2015, the Coastal Resources for Sustainable Development (CRSD) Project was brought to the Dong Dien shrimp farming area by the Department of Agriculture and Rural Development of Binh Dinh. Immediately after that, the shrimp farming area was re-planned for infrastructure, and a dike system to prevent salinity around the farming area was built. The water surface area in the farming area is also re-planned in the form: This side is the settling pond, the farming pond is in the middle, the other side is the discharge pond. Previously, the whole farming area had only one main culvert that both supplied water to the farming pond and discharged wastewater. Now, to limit pollution from the outside environment entering the farming pond, the project has built an additional discharge culvert, from which the water supply to the farming pond and the wastewater discharge are separate, so the environment of the shrimp farming water area here is guaranteed.

“Before releasing the shrimp, the water is discharged into a settling pond to be treated with disinfectant chemicals. The water stays in the settling pond for 5-7 days to allow all the toxic substances to decompose before being discharged into the farming pond. When the water reaches the farming pond, it is sterilized. If during the farming process, the technical parameters in the pond are found to be not up to standard, the farmer must change the water to change the environment in the pond so that the shrimp can grow better. The discharged water is transferred to a nearby waste pond for treatment before being gradually discharged into the environment through the drain. Thanks to the implementation of comprehensive measures to prevent and control diseases, and the organization of monitoring, timely detection and handling of outbreaks, shrimp farming in Dong Dien is increasingly bringing practical results,” said Mr. Pham Van Chay, a shrimp farmer in Dong Dien.

According to Mr. Pham Quang An, Deputy Head of the Department of Agriculture and Rural Development of Tuy Phuoc district, shrimp farmers in the area are now very strict in renovating and cleaning the bottom of the pond before releasing shrimp for the new crop. “Pond bottom improvement is a key factor in determining the success or failure of the farming season. Because, during the farming process, waste from leftover food and shrimp feces settle at the bottom of the pond, causing pollution and generating toxic gases. Therefore, after harvesting, when improving, the pond bottom must be dried thoroughly. If the pond bottom is not properly dry, when water is discharged into the pond for anaerobic farming, the shrimp will suffocate from oxygen, and healthy shrimp will turn upside down and die. In ponds that were infected with disease in the previous crop, farmers must use chlorine before releasing the shrimp,” Mr. An analyzed.

“Currently, in Tuy Phuoc, there are still many shrimp farming areas that do not have their own water supply and discharge systems, so the environment of the farming water is seriously polluted. For example, the Ho Uc shrimp farming area in Vinh Quang 2 village, Phuoc Son commune and the Kim Dong farming area in Phuoc Hoa commune, therefore, shrimp farming here often suffer from diseases due to polluted farming water. To reduce waste discharge into the environment in the two farming areas mentioned above, the province and district have planned to re-plan the farming areas in a way that the State and the people do together. However, due to waiting for financial support from the Central Government, the re-planning of the above farming areas has not been implemented yet," said Mr. Pham Quang An, Deputy Head of the Department of Agriculture and Rural Development of Tuy Phuoc District.

According to nongnghiep.vn