Preliminary Study of Fish Communities in an Estuarine Environment: The Ouladine Lagoon, Côte d'Ivoire

This work aimed to provide the first data on the structure and organization of the fish population in Ouladine lagoon. The ichthyofauna of the Ouladine lagoon was sampled monthly from November 2022 to February 2023 using artisanal and commercial fishing. Catches were taken using a wide range of fishing gear (gillnets, harpoons and cast net) over the entire exploitable surface of the Ouladine lagoon ecosystem. A total of 25 species belonging to 17 families and 9 orders were identified. The orders with the highest number of families and species are the Perciformes (5 families and 12 species), followed by the Characiformes (3 families and 3 species) and the Gobiiformes (2 families and 3 species). The best represented family is the Cichlidae with 8 species. The main species are Sarotherodon melanotheron (41.6%), Coptodon guineensis (16.92%), Coptodon zillii (10.23%) and Chrysichthys nigrogitatus (7.78%). Sixteen (16%) marine species and one vulnerable species (Sardinella maderensis) were recorded among all the catches. The Shannon-Weaver diversity and equitability indices calculated over the entire study period were 1.97 bits/individual and 0.61 respectively, reflecting a diversified and organized environment. These results will serve as a reference for future investigations into the monitoring and conservation of species in the lagoon.