Introduction
Aquaculture is the world’s fastest growing food production sector(Moriarty 1999). It was once considered an environmentally sound practice because of its traditional
polyculture and integrated systems of farming based on optimum utilization of farm resources, including farm wastes. Increased production is being achieved by the expansion of land and water under culture and the use of more intensive and modern farming technologies that involve higher usage of inputs such as water, feeds, fertilizers and chemicals. As a result, aquaculture is now considered as a potential polluter of the aquatic environment and a cause of degradation of wetland areas (Pillay,1992).