Assessing potential aquaculture sites on Lake Victoria using GIS and Landsat 8 Imagery.
Abstract
Aquaculture is the controlled rearing of aquatic animals and plants for food or natural resource enhancement. It is the fastest growing food production sector and has been greatly responsible for the growth of fish supply. Being an agricultural country, Uganda depends on capture fisheries and aquaculture. The trend in demand in the demand for fish has been increasing which calls for a boost in the supply and boosting can be done through aquaculture. Cage aquaculture is the rearing of fish and other aquatic organisms in closed systems immersed in water for purposes of rearing the organisms in captivity in open water bodies. Establishment of site suitability of an area for cage aquaculture is an important step in any aquaculture operation, affecting its success and sustainable development. Conventional methods in form of insitu measurements are used in selecting suitable sites for cage culture and have not been effective as they are slow, require a lot of money and a small area is covered, hence leaving out other areas outside the sampled area and limiting accuracy to only the sampled areas. This study aims at locating areas suitable for cage aquaculture development on Lake Victoria using GIS and remote sensing. Three bio-physical parameters of temperature, turbidity and chlorophyll a are being assessed to help locate suitable sites. Temperature helps follow the health of the lakes, chlorophyll-a concentration is the measure of the abundance of phytoplankton and turbidity is measure of water clarity and suspended solids.The parameters were retrieved using chosen algorithms, weighed to get their contribution to final output and the results overlaid to produce suitability maps. Temperature distribution in the western part of the lake was high than in the eastern part. Chlorophyll a and turbidity were higher at the shores than distances far away from the shores. Temperature and chlorophyll a had a higher output to the final result than turbidity. Areas near the shoreline including islands were found to be most suitable than all the other areas.