A description of the rice-prawn-fish systems of Southwest Bangladesh.

Between the late 1970s and the mid-1980s a small number of farmers in southwest Bangladesh began to test the stocking of giant freshwater prawn (Macrobrachium rosenbergii) in rice fields. Extremely rapid expansion has occurred since 1990, mainly because this prawn is sold to the export market and is thus of very high value compared with traditional crops. The modified rice fields, locally referred to as 'gher', have large peripheral trenches. Consequently, the surrounding dikes are much larger than those seen in typical rice-finfish operations. Although most farmers operating 'gher' systems also grow finfish and rice, few utilize the dikes for crops, and the farm components are generally not well integrated. Except for the systems found in one specific area, the focus of production has been on the prawns. Despite the potential realization of high profits, farmers who operate 'gher' are often in a state of considerable vulnerability. Farmers use high levels of inputs for which they require large loans that represent considerable risk. Additionally, environmental impacts associated with 'gher' systems may be key determinants of these systems' sustainability in the medium and long term. The 'gher' systems appear to be unique among rice-fish systems in that small-scale farms in an impoverished area are producing a high value product for an export market. However, because of the current constraints, the sustainability of the systems is questionable. Diversifying crops and decreasing costs, as opposed to increasing prawn production, is possibly the most effective strategy.