Multi-criteria evaluation approach to GIS-based land-suitability classification for tilapia farming in Bangladesh

Site selection is a key factor in any aquaculture operation, because it affects both success and sustainability. It can, moreover, solve conflicts between different activities, making rational use of the land. This study was conducted to identify suitable sites for development of Nile tilapia (Oreochromis niloticus) farming in Sitakunda Upazila (sub-district), Bangladesh, using GIS-based multi-criteria evaluation of water and soil quality, topography, infrastructure and socio-economic factors. ASTER image and eighteen thematic layers were analyzed using ENVI and ArcView software to identify the suitable areas for tilapia farm development. A constraint layer was used to exclude areas from suitability maps that cannot be allowed to implement tilapia farming. A series of GIS models were developed to identify and prioritize the most suitable areas for tilapia farming. The output of the model clearly indicates the location and extent of tilapia farming areas on different suitability scales, i.e. most suitable (7,744 ha), moderately suitable (2,479 ha), and not suitable (838 ha). Model outputs were assessed against field verification data, and were consistent. Because existing aquaculture covers only 1,540 ha of land in the study area, the potential for expanding tilapia farms should take into consideration socio-political and environmental issues. The results are encouraging in terms of tilapia culture development and suggest that grassland-agriculture areas could be used for sustainable development of tilapia farming to diversify the economic activities of rural communities.