World Aquaculture 13 The region is a flat, low-lying delta, mostly comprising the floodplain of three large and converging rivers. The Big Feni River flows on the southeast and the Meghna River flows on the western side of the study area. The study area was divided into three zones under three thana (sub-districts) on the basis of a road network and availability of water sources, khas land (i.e., government-owned accreted coastal land), aquaculture farms, mangrove forest, cyclone-affected area, embankment, culture species, and fry sources. Aquaculture in the Study Area The area in aquaculture ponds was assessed using GIS. The topographic map published by the survey of Bangladesh in 1999 at a scale of 1:10,000 and the 2006 topographic map of Noler Char and Char Langulia were used to develop thematic maps. The base map with the union boundary of Noakhali Sadar, Com panigonj and Sonagazi thana were demarcated using ArcView GIS software. Thematic maps were marked as union boundaries, water areas, road network, embankments, and land use. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery of the study area acquired in 2007 was used to identify geographical features. The image processing software for the analysis was ENVI. ArcView software was used to digitize all classified and other necessary maps. Aquaculture activities were identified in 1694 ha of the study area (Fig. 2), similar to previous observations (Shahid et al. 1992, Venkataratnam et al. 1997).Water bodies that support aquaculture production, such as rivers, canals, and tributaries of the study area are shown in Figure 3. Greater aquaculture production from every water body type (such as pond, gheer, khal, and waterlogged areas) came from Noakhali Sadar region than from the two other zones in the study (Table 2). Aquaculture has increased rapidly since 1990 in the Feni-Noakhali coastal region as a result of government khas land leasing. Availability of land and water resources—such as rivers, canals, and tributaries—make this area suitable for aquaculture. There are also various value chain facilities, including fry sources, hatchery, labor, and market, that are located in this zone to support aquaculture development. The large areas of intertidal land in Bangladesh are especially suitable for prawn production (Fleming 2003) and growth in the industry is being encouraged through a number of aid programs and government initiatives. Carp species, native and exotic, represent Fig. 2. Aquaculture areas of the Feni-Noakhali coastal region. Table 1. Significance ratings and weights of the relevant criteria in connection to perceived value of mangrove forest. Parameter Ranking Temporary weight Final weight Wi House building materials 1.4 0.571 0.106 Fuel wood 1.0 0.800 0.148 Grazing land 1.2 0.667 0.123 Foot bridge 1.0 0.800 0.148 Fishing pole 1.5 0.533 0.099 Fencing 1.5 0.533 0.099 Furniture 0.8 1.000 0.185 Cyclone protector 1.6 0.500 0.093 Sum 5.405 Table 2. Total fishery production from aquaculture and contribution in local demand at the study area. Production Noakhali Sadar Companigonj Sonagazi Fish (mt) 7927 2610 3480 Indian carp (%) 40 Chinese carp (%) 25 Tilapia (%) 20 Pangus (%) 10 Other (%) 5 Prawn (mt) 233 41 1020 Total production (mt) 8160 2651 4500 Total fish demand (mt) 13177 3851 9420
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