Diversity and assemblage of Ichtyofauna in an unexplored tropical aquatic ecosystem: Inzia River, Congo basin

Ichthyofauna diversity and assemblage in tropical aquatic ecosystems, particularly those of Central Africa, although rich in biodiversity, are far from being sufficiently known. The present study examines fish biodiversity along the tropical Inzia River catchment located in the Democratic Republic of Congo. From July to September 2022, a total of 22 stations were sampled and surveyed for an effort duration of 24 hours per station using various fishing equipment and techniques. These involved the use of still nets, floating lines, hawksbills, longlines, and catches from local fishermen. A total of 17,187 fish were caught, most (92.3%) of which were captured by the static net. Analysis of the data revealed 91 formally identified fish species, belonging to 57genera, 25 families, and 12 orders. Seven adult specimens were unknown, and their fin fragments were taken and preserved for identification by DNA analysis at the Royal Museum for Central Africa in Tervuren, Belgium. Fish species diversity was higher in the Inzia River than in its tributaries and showed an upward trend from the lower to the middle reaches of the basin. Our results confirm the abundant fish biodiversity in tropical aquatic ecosystems, and the unidentified individuals could probably be new species.