Determination of Land Cover Changes and Suitable Shrimp Farming Area Using Remote Sensing and GIS in Southwestern Bangladesh

Abstract

The present study was conducted to identify and quantify suitable sites for shrimp farming at Debhata upazila of Satkhira district, Bangladesh, using remote sensing technique and GIS. The spatial and temporal changes of land cover were determined using Landsat images of 1977, 1990, 2000 and 2004. The Landsat TM data and secondary data that included land elevation, crop intensity, land capability association and soil salinity along with primary data of water and soil characteristics such as pH, dissolved oxygen, salinity, phosphorus, potassium, tidal fluctuation and soil texture were used to produce a shrimp farming suitability map. The map was also verified by integrating with different facilities such as sources of water, sources of shrimp post larvae, roads, ice factories, shrimp markets, shrimp processing plants and NGOs. Shrimp farming areas were gradually increased while cropland areas were gradually decreased that reveals an unplanned horizontal expansion of shrimp farms. The shrimp farming suitability map indicates that out of 17362 ha available land, 5756.82 ha (33.14 %), 2336.02 ha (13.45 %), 3089.42 ha (17.78 %) and 6188.34 ha (35.62 %) were under very suitable, suitable, moderately suitable and unsuitable categories, respectively. The study suggests that shrimp farming should be confined within the very suitable areas to avoid horizontal expansion of shrimp farming without any environmental and social consequences. The present study has demonstrated the usefulness of remote sensing technique and GIS to select suitable sites and as a tool for planners to develop strategic plans for sustainable aquaculture development.