Fishermen Local Knowledge and Aquatic Environmental Change: Impacts on Fishing and Adaptation Strategies in Volta Basin

Climate researches predict that climate change will have an important impact on aquatic and terrestrial ecosystems. However, many fishermen do not have a lot of knowledge about climate change or how it might affect their fish catch yields and overall fishing operations in the future. The objective of this study was to assess local fishermen’s perception of global change on the ichthyofauna of the Volta Basin in Burkina Faso. Focus group interviews were conducted between March 2019 and July 2020 in 19 reservoirs of the Volta Basin. A total of 242 fishermen divided into 34 groups participated in the interviews. The results showed that fishermen are aware of climatic and anthropogenic threats to fish fauna. According to them, these global changes lead to important modifications in the structure of the ichthyofauna ranging from seasonal mortality of fish (Mormyridae) to the extinction of certain species such as those of the genera Lates, Hydrocynus and Heterotis. These changes also lead to a loss of fish habitat through silting and lower water levels in the reservoirs. Statistical analysis of the collected data showed that the main factors threatening the structure and dynamics of fish are mainly agriculture and market gardening around the dam lakes, the temperature increase and the trend of decreasing rainfall. Thus, the main pressures responsible for the mortality and/or extinction of fish are market gardening pollution (100%), bad fishing practices (63.15%) and high temperatures (47.5%). As for adaptation measures and management strategies, the most important were training and sensitization of stakeholders (78.94% of citations) followed by fish stocking (21.05%). This endogenous knowledge is important for the development of climate change adaptation programs.