Shrimp farming is a pillar of Vietnamese seafood exports, but it faces disease risks and environmental pollution. Recirculating aquaculture system (RAS) technology is seen as a way to better control farming conditions and develop more sustainably.
Limits of traditional earthen ponds
Earthen-pond shrimp farming depends heavily on natural water sources and weather. Frequent water exchange is costly and risks introducing pathogens from outside, while untreated wastewater discharged to the environment causes pollution and spreads disease between farming areas.
What is a recirculating aquaculture system?
In RAS, water is treated and reused continuously rather than discarded. Water from the tanks passes through mechanical filtration, biological filtration and disinfection before returning.
- Mechanical filtration removes solids and leftover feed
- Biological filtration converts toxic ammonia to less toxic forms
- Aeration and dissolved-oxygen control for the shrimp
- Disinfection and microbial control of recirculated water
Microbial control and biofloc
A key strength of recirculating systems is active control of the water's microbiome. Biofloc technology harnesses beneficial microbial communities to process waste and provide supplementary natural feed. A balanced microbiome yields a more stable environment, limits pathogenic bacteria and reduces the need for antibiotics.
Benefits of RAS
- Lower disease risk by limiting external pathogen entry
- Substantial water savings through reuse
- Less environmental pollution via wastewater control
- Higher stocking density on the same area
In modern shrimp farming, managing water is managing the shrimp's health; controlling the water environment is the key to sustainably reducing disease.
Challenges and directions
Feed and nutrition management
In RAS, feed management is crucial because leftover feed is the main source of water pollution. Feeding the right amount at the right time cuts costs and eases the load on filtration, keeping water quality stable.
- Feed to actual demand to avoid excess
- Track growth to adjust rations
- Use biofloc to tap natural nutrients
Fit for the Mekong Delta
The Mekong Delta is a key shrimp region but is strongly affected by saline intrusion and climate change. Recirculating technology reduces dependence on external water and stabilizes production. Still, investment levels must match each household's capacity; semi-recirculating models can be a sensible transitional step before full systems.
RAS requires large upfront investment, complex operation and a stable power supply, so choosing an appropriate scale and level of automation for each household is crucial, especially in the Mekong Delta. ASTRI Institute regards recirculating aquaculture and water-treatment technology as an important research, application and technology-transfer direction, aiming to develop practical water-treatment and microbial-control solutions to help the shrimp sector grow more efficiently and sustainably.