Dikes, rice, and fish: how rapid changes in land use and hydrology have transformed agriculture and subsistence living in the Mekong Delta

Abstract

The recent development of high dikes to support rice production, upland crops, cattle rearing, and commercial aquaculture in the Vietnamese Mekong Delta has significantly diminished wild fish catch and aquatic animals that are important food sources for the poor. Changes to agro-ecological systems in An Giang Province during three periods are reviewed: before 1975, when a network of canals was established; during the Doi Moi policy reforms of the 1980s, when a rice-based farming system based on low or August dikes was introduced; and more recently, when a new farming system based on high dikes replaced the low dike system. This most recent transition occurred in parallel with the introduction of large-scale commercial aquaculture and the market economy. Under pressure from government targets and market forces, most farmers are now using the high dikes, fertilizers, pesticides, and pumping technology to produce three rice crops each year. However, the new production systems have severely reduced the habitat available to inland freshwater wild fish and other aquatic food resources. This has negatively impacted nutrition for many poor families who had depended on wild fish caught in the commons for much of their food and offers lessons for development of other tropical delta regions. This paper proposes a research agenda that would investigate the socioeconomic, nutritional, and water and energy use impacts of the changes in production systems that have occurred in rural communities in the Mekong Delta.

Climate precarity in rural livelihoods: Agrarian transformations and smallholder vulnerability in Vietnam

“…Upstream provinces previously dependent on floating rice systems pushed to intensify rice production even more, from two crops a year to three, and triple cropping became possible in the mid‐1990s, when farmers began using water pumps to drain fields and plant even earlier in the year (Le Coq & Trebuil, 2005). Authorities supported expanding to a third crop as a way to create jobs and incomes during the fall flood season, but even higher protection dikes were needed (Nguyen et al, 2019). Existing ‘August’ dikes (which would hold back floods only until August, when the monsoon rains would overtop them) were converted to higher dikes of 5+ m or more; farmers were required to contribute financially and through physical labour to help construct these earthen dikes, adding to demands on their time.…”

Health and wellbeing implications of adaptation to flood risk

“…First, they can alter ecosystems and habitats with subsequent negative implications for the health of affected populations. For example, Kien Nguyen et al ( 2019 ) show that dikes constructed in the Mekong Delta disproportionately affect the nutrition of poorer populations that rely on wild fish as part of their diet. The construction of dams also acts to change ecosystems; changes in flow, river ecology and salinity in proximity to human settlements can result in increased transmission rates of vector borne diseases, including malaria and schistosomiasis (Steinmann et al 2006 ), particularly in tropical and subtropical environments (Lerer and Scudder 1999 ).…”

“…Hard Infrastructure Food security: change in crops, change in diet, malnutrition In the Mekong Delta the construction of Dikes has affected access to wild fish, and the diet of local people reliant of fish from common areas (e.g. Kien Nguyen et al 2019 ). Hard Infrastructure Public Infrastructure: Access to healthcare, protection of key healthcare assets such as hospitals Flood embankments in Bangladesh make travel easier, improving the process of referrals and of home visits by community workers (e.g.…”

Small‐scale fisheries and local food systems: Transformations, threats and opportunities

“…As well as making use of environmentally degraded waterbodies, aquaculture and culture‐based fisheries can also themselves degrade aquatic environments through the interaction of introduced or escaped fish with wild fish, notably the Nile Perch ( Lates niloticus , Latidae) in Lake Victoria (Aloo et al, 2017), or through the effluents released from culture systems (Naylor et al, 2021). It can also create competition for space and involve the enclosure of coastal and inland waters, resulting in conflict and loss of access for small‐scale fishers (Cohen et al, 2019; Nguyen et al, 2019; Stonich & Vandergeest, 2001; Sultana & Thompson, 2011). Furthermore, the share of freshwater fish raised on compound feed, which is made largely from terrestrial and some marine ingredients, has increased over the past two decades (Naylor et al, 2021).…”