The evolution of aquatic agricultural systems in Southwest Bangladesh in response to salinity and other drivers of change

Aquatic agricultural systems (AAS) in coastal Southwest Bangladesh have evolved in response to a number of stimuli and constraints including improving market access, technological change, and salinization. Farming systems in the region are highly dynamic, and are characterized by the integration of varying combinations of freshwater prawns, rice, fish, vegetables, and brackish water shrimp. This paper examines the developmental history, productivity, and profitability of three distinct AAS: a low-salinity freshwater prawn-dominated system; an intermediate-salinity-mixed prawn and shrimp system, and a high-salinity shrimp-dominated system. Productivity, cropping intensity, and profitability are found to be highest in the diversified low- and intermediate-salinity systems, and lower in the high-salinity system, where cultivation of rice and vegetables is no longer possible. The paper concludes that more diverse integrated systems reduce risk and vulnerability for farming households. Salinization is found to be a double-edged sword – proving a stimulus to diversification at low levels, but reducing agro-biodiversity at higher salt concentrations. While the adaptation strategies in all systems have been successful in maintaining or improving most, though not all, system functions due to high levels of social resilience, support for effective community-based adaptation strategies will enable continued transformation and adaptation to future drivers of change.