3 COMMUNITY-BASED FISH CULTURE IN SEASONAL FLOODPLAINS Mark Prein and Madan M. Dey WorldFish Center GPO Box 500, 10670 Penang, Malaysia Prein, M. & M.M. Dey. 2006. Community-based fish culture in seasonal floodplains. In M. Halwart & A.A. van Dam, eds. Integrated irrigation and aquaculture in West Africa: concepts, practices and potential, pp. 17–26. Rome, FAO. 181 pp. Abstract During the rainy season in extensive river floodplains and deltaic lowlands, floods lasting several months render the land unavailable for crop production for several months each year. These waters are considerably underutilized in terms of managed aquatic productivity. This raises the opportunity to enclose parts of these floodwater areas to produce a crop of specifically stocked aquatic organisms aside from the naturally occurring “wild” species that are traditionally fished and are not affected by the culture activity, overall resulting in more high-quality, nutrient- dense food production and enhanced farm income for all stakeholders, notably the poor. The WorldFish Center and its national partners recently tested the concurrent rice-fish culture in the shallower flooded areas and the alternating rice-fish culture in the deep-flooded areas of Bangladesh and Viet Nam through a community-based management system. Results indicate that community-based fish culture in rice fields can increase fish production by about 600 kg/ha/year in shallow flooded areas and up to 1.5 tonnes/ha/year in deep-flooded areas, without reduction in rice yield and wild fish catch. Introduction The past decade has seen growing recognition of the crisis facing the world’s water resources and the need for concerted action to use these more efficiently. The efficiency of water use (or water productivity) can be increased by producing more output per unit of water used, or by reducing water losses, or by a combination of both. So far, strategies for increasing output have been limited to crop cultivation only. Water productivity at several organizational levels can be increased further by integrating fish and other living aquatic resources into the existing water use systems. Such opportunities of integration include community-based fish culture in irrigation schemes and seasonal floodplains. A variety of studies show that reservoirs and canals of irrigation systems continue to yield substantial fish harvests, which are important sources of protein and livelihoods for the poor and landless households. Yet the current use of irrigation systems and floodplains for fish production falls far short of potential. In seasonal floodplains, fish production essentially emanates from capture activities by seasonal or part-time fisher- farmers where wild fish enter, reproduce and are harvested from the flooded fields. In Cambodian floodplains, the value of fish caught through trap ponds within rice fields reaches 37 to 42 percent of that of rice production (Gregory and Guttman, 1996; Guttman, 1999). A number of studies have been conducted in the 1980s to test the technical feasibility of culturing fish in seasonally flooded rice fields in India (Roy et al., 1990; Das et al., 1990; Mukhopadhyay et al., 1991), Bangladesh (Ali et al., 1993, Ali et al., 1998), Cambodia (Gregory and Guttman, 1996; Guttman, 1999, 2000), and Viet Nam (Rothuis et al., 1998a; Rothuis et al., 1998b). These studies show that fish production can be increased by more than 1 tonne/ha/year by stocking flooded ricefields with fish (i.e. individual farmers fencing their plots and stocking fish during the flood season). In addition, the culture of fish within rice fields can increase rice yields, especially on poorer soils and in unfertilized crops where the fertilizing effect of fish is greatest (Halwart, 1998). Savings of pesticides and earnings from fish sales lead to increased yields and result in net incomes that are 7 to 65 percent higher than for rice monoculture (Halwart, 1998). But the adoption of this technology by farmers has 17