Diversity, Length-weight structure and Condition Factor of fish species and physicochemical changes in four reservoirs in Volta basin, Burkina Faso

The human activities combined to global warming negatively impact aquatic ecosystems mainly in the areas with high human density. This study was undertaken to determine fish diversity and environmental parameters in four reservoirs in Volta basin of Burkina Faso. To do so, from May to June 2020 were collected and identified as species, and the physicochemical variables measured. Thirty (30) fish species were identified in these reservoirs during the research and 601 individuals of three Cichlids species (Sarotherodon galilaeus, Oreochromis niloticus and Coptodon zillii) were measured for total length and weight. Samendéni reservoir shows the betted physico- chemical conditions: a high value of Transparency (>165 cm) and a low value of Nitrate (0 mg. L-1). By contrast, the other sites like KoubriAB seem to be influenced mostly by anthropogenic pressures; therefore they show a low value of Transparency (< 15 cm) and a high concentration for Nitrate (8. 7 mg. L-1), characterizing the presence of human activities. The allometric results of growth, except for the Coptodon zillii, globally show that b values reach up around to 3. A total of 30 fish species were encountered in this basin during this study with specific richness of 18±1 per site.