Vaccination and water improvement in the Mekong Delta

The study was just published in the Dutch International Agriculture newsletter, within the framework of the DeltaVax project in the Combitrack Vietnam program supported by the Dutch Government (implemented from 2024 to 2027) in the context of the pangasius industry facing increasingly strict requirements from the high-end market.

Currently, the pangasius farming model is mainly intensive farming with high stocking density. Research in the Mekong Delta shows that people stock fish at many different densities. However, farming at high density can easily increase stress, reduce growth rate, increase feed conversion ratio (FCR), and increase disease rates in fish. The expert group recommends that farmers maintain optimal density (30-40 fish/m2) combined with water quality management, especially dissolved oxygen, ammonia concentration and turbidity – which can significantly improve survival rates and reduce the need to use chemicals and antibiotics.

Regarding water quality, farmers should check indicators at least twice a week, and preferably every day, to ensure low ammonia and nitrite concentrations. You should add probiotics or biofloc technology to help improve water quality, limit the growth of harmful bacteria, stabilize the microflora and reduce dependence on chemicals. In addition, it is necessary to periodically dredge sludge from the pond bottom to limit the accumulation of organic waste at the bottom of the pond – which leads to the generation of toxic gases such as hydrogen sulfide – which negatively affects fish health.

The study also shows that farmers need to switch from disease management models using chemicals and antibiotics to preventive measures, such as vaccination. Experiments show that vaccination of pangasius fingerlings is to prevent diseases caused by major bacteria such as Edwardsiella ictaluri and Aeromonas hydrophila helps improve survival rate and reduce dependence on antibiotics, building a more sustainable and safer farming model.

The stages of harvesting, transporting and slaughtering are also issues noted in the study. The expert group recommended improvements by using soft nets, limiting the time fish are exposed to air and optimizing transport conditions to “enhance fish welfare, while also improving the meat texture and flavor of the final product”. Accordingly, it is necessary to apply humane slaughter methods, because many current methods still cause fish to suffer prolonged pain before death, affecting both ethical factors and consumer feelings.

According to Mr. Joe Pearce, DeltaVax project representative, consumer demand in the high-end market for humanely raised seafood products is increasing, especially in Western markets, where regulatory agencies and retailers are applying stricter requirements on animal welfare.

Currently, ASC and GLOBALG.AP certifications have integrated some content related to fish welfare, however there are still no specific regulations for pangasius species such as operating procedures, farming density and humane slaughter methods. These contents are currently not applied or standardized in pangasius farming.

At many processing plants, especially those exporting to China and other Asian markets, fish are often bled without being stunned first. This method allows for high processing speeds, with an estimated two fish being dissected per second. However, the research team said that many fish still moved their fins or tried to swim after their gills were cut, showing that they were still conscious and had to endure pain for a long time.

For the EU and UK markets, electric stunning is more commonly used. However, dry stunning, where the fish is taken out of the water and stunned on a conveyor belt, is still the current standard method. Although it allows for quick handling, this method can still cause stress to the fish before stunning is fully effective. In addition, due to concerns about slowing down the production line, the stunning step is usually only applied to fish exported to Europe, while fish exported to North America and other Asian countries are often killed without going through this step.

Although fish welfare is not currently a mandatory requirement under EU regulations, this issue is increasingly being emphasized, especially in Nordic countries – where consumers and retailers emphasize humaneness and sustainability. Research shows that people are willing to pay a higher price to buy welfare-certified pangasius, showing the market potential for farmed products that meet welfare standards, although cost is still an important factor in Vietnam.

“The concept of fish welfare is still quite new to many people. Studies show that better fish care will help make fish healthier, improve product quality and increase profits for farmers, giving consumers the opportunity to access products of superior quality,” said Mr. Joe Pearce.

According to Ms. Ingrid Korving, Dutch Agricultural Counselor in Vietnam, as the largest importer of Vietnam in the EU overall and the largest importer of Vietnamese pangasius products in the EU, the Netherlands sees increasing expectations for responsible and welfare-focused aquaculture practices. Improving seafood welfare is closely linked to better product quality, stronger market access and reduced environmental impact. This strengthens product quality, market access and long-term competitiveness.

“The Vietnamese seafood industry has huge potential, and by adopting higher welfare standards, it can build stronger trust from European consumers, while creating more sustainable and resilient value chains,” she said.

Currently, Vietnam is a key producing and exporting country, accounting for more than 90% of the total pangasius export turnover in the world. In 2024, the industry’s export value will reach 2 billion USD, accounting for about 20% of the country’s total seafood export value.

Vietnam – the Netherlands have a history of more than 50 years of cooperative relations, more than 10 years of signing a Strategic Partnership Agreement (SPA) on food security and sustainable agriculture, with many joint initiatives that have been implemented, including the field of sustainable and responsible aquaculture, improving farming conditions, animal health and reducing environmental impact, contributing to improving the value and sustainability of Vietnam’s seafood supply chain.