Increasing solutions to control shrimp diseases

In 2014, the situation of aquatic diseases in general and shrimp diseases in particular remained complicated. The area of ​​shrimp farming affected by diseases did not decrease despite many measures taken by all levels, ministries and branches.

Not yet worried

According to the Department of Animal Health, in the first 11 months of this year, white spot disease occurred in 250 communes and 69 districts in 22 provinces and cities. The total area of ​​shrimp farming affected by the disease was 22,624 hectares, accounting for 3.3% of the total farming area of ​​the country. The disease occurred in white-leg shrimp (WL) and black tiger shrimp, shrimp aged 10-110 days after stocking. Black tiger shrimp suffered the most damage, with an area of ​​13,529.47 hectares, accounting for 59.8%; the rest was WL.

Compared to the same period in 2013, the white spot disease outbreak occurred in a narrower area, with 250 communes in 22 provinces affected (in 2013, 280 communes in 28 provinces were affected), but the diseased area was 1.85 times larger. The country had 3 provinces declaring the epidemic: Soc Trang, Nghe An, Quang Ninh; Soc Trang was the province with the greatest damage with 10,933.82 hectares, accounting for 48.33% of the total area affected by white spot disease nationwide.

Also in 11 months, acute hepatopancreatic necrosis disease occurred in 233 communes in 22 provinces and cities. The total area of ​​shrimp affected by the disease was 5,591.7 hectares, accounting for 0.82% of the total shrimp farming area of ​​the country. The disease occurred in both whiteleg shrimp and black tiger shrimp aged 10-103 days after stocking; of which whiteleg shrimp accounted for 63.61%. Compared to the same period in 2013, acute hepatopancreatic necrosis disease occurred 1.21 times more widely in the number of communes, but the total area affected by the disease remained the same.

Shrimp disease is recurring in many localities.

Old cause, new problem

The Department of Animal Health said that the risk of disease in shrimp is very high; 92/100 communes in 4 investigated provinces (Thai Binh, Soc Trang, Bac Lieu, Ca Mau) of shrimp are at risk of disease. Regarding the cause of white spot disease, scientists believe that the WSSV virus (White Spot Syndrome Virus) is still the main culprit. The transmission mechanism of white spot disease is very diverse, such as transmission from parent shrimp, from the environment, food sources (some species of mollusks and crustaceans are food for shrimp, shrimp have a self-eating mechanism, so it is transmitted from sick shrimp to healthy shrimp)...

For acute hepatopancreatic necrosis disease (AHPNS), results from many studies show that Vibrio bacteria, commonly V.Parahaemolyticus, V.Harveyi, V.Vulnificus, V.Ordallii, are the culprits related to early mortality syndrome in shrimp. To control these bacteria, shrimp farms have used many antibiotics (Tetracycline, Oxytetraxyline, Rifamycine...); chemicals (Iodin, KMnO4); biological products including 7 commonly used types such as ET800, Doray Men, Biotec A Men, ZP-25... to treat ponds. The rate of shrimp hatcheries in the Central region using antibiotics and chemicals is currently up to 90%. The Directorate of Fisheries has identified a number of substances (such as Chrorine, TCCA...) that are very effective in destroying bacteria that cause AHPNS.

Proactive prevention

In 2014, 35 provinces and cities developed and submitted disease prevention plans to competent authorities for approval. Of these, 26/35 provinces and cities were allocated a total budget of over 25.2 billion VND. The remaining 9 provinces and cities had plans but did not allocate funds for implementation. Compared to 2013, the budget for shrimp disease prevention increased 2.5 times.

The Department of Animal Health has established 29 inspection teams in 23 provinces and cities. Regional veterinary agencies also regularly inspect and urge disease prevention in key provinces. Many shortcomings and inadequacies have been discovered in the prevention of aquatic diseases, such as: statistics on farming areas, diseased areas, reporting, declaration, sampling, testing, disease diagnosis, quarantine management of aquatic breeds and veterinary drugs.

Synchronized execution

The Ministry of Agriculture and Rural Development has organized many scientific seminars on disease prevention in brackish water shrimp, especially establishing the Steering Committee for Disease Prevention in brackish water shrimp; implementing tasks of disease prevention in shrimp nationwide. The Steering Committee is the focal point for coordinating relevant units of the Ministry of Agriculture and Rural Development, localities, domestic and foreign scientists related to disease prevention activities in shrimp, shrimp farming techniques. At the same time, it coordinates and unifies tasks related to research on disease prevention, treatment, disease surveillance; environmental monitoring and warning, etc.

Deputy Director General of the Directorate of Fisheries Pham Anh Tuan said that many farming protocols and processes have been proposed by research institutes, but when implemented, the level of success has not been repeated. That is, the same farming process but the previous crop was successful, the next crop may fail. White spot disease is caused by the WSSV virus, shrimp farmers are often advised to use Chlorine to treat water. But in reality, using this chemical is not very effective, it is necessary to find other substances. On the other hand, the market has many environmental improvement substances that are not of good quality. The current solution of using antibiotics and chemicals to prevent epidemics is not feasible, potentially posing a risk of insecurity for the shrimp farming industry. Therefore, antibiotics need to be replaced with biological products.

Deputy Minister of Agriculture and Rural Development Vu Van Tam stated that it is necessary to raise farmers' awareness by training and communicating effective shrimp farming models, regulations on biosafety and scientific pond design. It is necessary to build and apply a combination of both passive and active disease surveillance models, in order to provide disease epidemiological maps and early warnings about the epidemic situation. Institutes need to research sustainable farming models, possibly in the direction of combining shrimp and fish farming, research bacterial strains with antibacterial properties against pathogenic bacteria, and research substances to help improve shrimp resistance. The veterinary sector must properly manage drugs used in aquaculture...

According to Vietnam Fisheries