Comparative sustainability analysis of aquasilviculture and other shrimp farming types in the Mekong Delta, Vietnam

In this study, we compared the sustainability of the Integrated Mangrove Shrimp
Aquasilvi-culture (IMSA) with that of the Intensive (INT), Improved Extensive (IE)
and the hybrid forms of farming shrimp in Tra Vinh, a coastal province in Mekong delta, Vietnam. To quantify sustainability, we identified 20 indicators representing one of the three fields of sustainability: ecological, financial and social. Our study did not quantify the ecosystems services because aside from aquatic products, the local IMSA provides only timber. We surveyed a total of 132 farms. Of these, 103 farms were non-hybrid consisting of 26 IMSA, 48 INT and 29 IE. The hybrids were either IE-INT (18), INT-IMSA (7), or IE-IMS (4). We also collected online the rating of 38 experts for the sustainability indicators. Furthermore, to fit all data in one graph on a scale of 1 to 100 (Zhang et al 2012), we transformed the original average values of the parameters.The expert panel rated highest the economic indicators, followed by social and ecological indicators. INT and IMSA farms were found to be significantly different in eight farm parameters; while IE and hybrid farms differed in five parameters. INT farms used more chemicals but frequency of disease outbreaks remained higher than in IE and IMSA. However INT farms scored higher for most economic indicators, while IMSA scored better for social and ecological indicators. Results of the study show that low cost start-up and operation, as well as the presence of mangroves, can reduce the social and ecological risks of shrimp farms located in fragile coasts of tropical deltas. Although shrimp aquasilviculture has a small contribution to the shrimp value chain, IMSA gives farmers an option to farm certified organic shrimp. More importantly, appropriate application of IMSA can also contribute to sustaining coastal livelihoods during sea level rise induced by climatic changes.