The Fish Fauna of the Future Large Size Reservoir of Ouessa, on the Mouhoun River, Burkina Faso

Abstract

Reliable and basic information on fish are required for the sustainable management of a fishery. For this reason, the fish fauna of the future reservoir of Ouessa in the low section of the Mouhoun River, Burkina Faso is studied. In order to describe the fish community, the fish were sampled in March 2020 thanks to cast nets and gill nets. They were sorted into species and each fish was weighted at the nearest 0.1 g and its total length measured at the nearest mm. The landings of commercial fishermen were also observed. In total, 1059 fishes were collected and grouped into 42 species, 27 generas and 16 families. The dominant species were Synodontis nigrita, Synodontis schall, Marcusenius senegalensis, Schilbe intermedius, Brycinus nurse and Alestes baremoze. However, the compilation of diverse sources suggests the presence of nearly 70 species. The index of Shannon-Weaver (3.97), the values of the condition factor, the fish size and the presence of intolerant species indicate the relatively good conditions of the aquatic ecosystem. Among the 24 dominant species, 54% have a positive allometric growth, 42% a negative allometric growth and 0.04 an isometric growth. This study builds the basis of sustainable management of the future reservoir of Ouessa that is planned to be the largest one of the country (40,000 ha large).