Intensive shrimp farming in Vietnam is less pollutive than that in China and Indonesia, mainly because production is less intensive. But investments in water treatment are needed, now that the Vietnamese government wants to intensify shrimp production.
Shrimp production in brackish water often destroys mangrove forests in coastal regions, but in Anh's research area, mangrove trees have been replanted. While Vietnam is ranked third on the list of largest shrimp producers in the world, not much has been published on the environmental performance of the Vietnamese shrimp sector in international literature, says co-author Simon Bush from the Environmental Policy Group.
The more intensive a shrimp farm is, the more pollutive it becomes. Compared to very intensive shrimp farms in China and Indonesia, pollution in intensive farms in Vietnam is relatively low, says Bush. 'While individual farmers do exceed the norms for water pollution and contamination of sediment in the ponds, this is not the case across the board. Production doesn't have to be pollutive.'
As such, there are options for Vietnamese shrimp farmers to improve their performance. Waste management and re-use of water are general recommendations from Anh and her colleagues. 'Some farmers dump contaminated sediment into surrounding canals', explains Bush. 'It would be better for them to store and dry these in sedimentation ponds. It's a matter of good housekeeping.'
Apart from this advice, Anh and her colleagues advocate water treatment technologies. 'These are available in Vietnam, but not many shrimp producers invest in them. Reusing pond water, which has high concentrations of nitrogen en phosphates, for vegetable production appears to be another promising option.
'We have been able to find many possible improvements, but the farmers need incentives to invest in environmental technology and education', says Bush. 'Markets haven't come up with incentives for improving the water quality yet. Environmental certification systems like GlobalGAP can offer shrimp farmers access to European markets, but not better prices.'