MEP were contracted by a mining company in Sierra Leone to complete a study of the freshwater fish species located in the Tonkolili and Mawuru river as part of on-going EIA work. These rivers have received little study to date, both in terms of species abundance and diversity. MEP working together with Fourah Bay College, completed three separate studies, commencing with a baseline survey and followed by both wet season and dry season surveys. The fieldwork involved both the netting and collection of fish samples from a variety of locations up and down the rivers. The project has led to MEP being able to create a detailed understanding of the species that inhabit the Tonkolili and Mawurur rivers throughout the year.