The conservation status and the vulnerability to fishing pressure of the ichthyological population of the Bandama River located in the Marahoué Region (Côte d'Ivoire) were assessed. Sampling of fish fauna was conducted from September 2019 to November 2020 using experimental and artisanal fisheries. The results of International Union for Conservation of Nature show that, the majority of the fish species (88.7%) inventoried were classified as "least concern". The "high to very high" and "very high" categories are represented respectively by two species and one species. These include Heterobranchus longifilis and Malapterurus electricus, which belong to the "high to very high" vulnerability category, and Clarias gariepinus, which belongs to the "very high" category. In addition, 79.87% of the species in this stand have vulnerability between "low" and "moderate".

Demographic structure and level of exploitation of Pellonula leonensis in the Aghien lagoon were examined by applying length-weight relationship (LWR), Condition factor, Von Bertalanffy model, Mortality parameters, Exploitation rate, Recruitment pattern and Beverton and Holt analysis. Fish population were sampled monthly during one year between June 2014 and May 2015 from artisanal and experimental captures in the Aghien Lagoon. Except LWR and the condition factor, studied parameters were provided by the FiSAT II package. The negative allometric growth (b = 2.61) was reported for Pellonula leonensis. Mean values of the condition factor (CF) vary significantly from one month to another (Anova, p ˂ 0.05). Concerning growth parameters, results indicated that the asymptotic length (L∞) has been estimated at 126.84 mm SL, growth coefficient (K) was 0.67 year -1 and growth performance index (Φ') was 2.03. Growth modelization revealed 4 cohorts for Pellonula leonensis. The estimates of the total (Z), natural (M) and fishing (F) mortalities were 1.87, 0.92 and 0.95 year -1 respectively. The recruitment pattern was continuous throughout the year with two Gauss curve. The exploitation rate obtained (E = 0.51) was close to E0.1 (E0.1 = 0.55), thus indicating that the P. leonensis stock is in an optimum state of exploitation.

This study focused on the diversity of fish fauna, its conservation status and its vulnerability in the Aghien freshwater lagoon (southeast of Côte d'Ivoire). For the fish data collection, two sampling approaches were used: experimental fishing and artisanal fishing. As a result, 80 species observed in this lagoon are distributed into 55 genera, 27 families and 10 orders. The best represented orders are the Perciformes, Siluriformes, Osteoglossiformes, Characiformes, Cyprinodontiformes and Pleuronectiformes. The Cichlidae, Mormyridae and Clupeidae represented the best diversified family. With an occurrence of 100%, the most frequent species are: Brycinus longipinnis, Chrysichthys nigrodigitatus, Pellonula leonensis, Schilbe intermedius and S. mandibularis. In the whole fish population, according to IUCN red list, four species where described as Near Threatened (Coptodon walteri, Marcusenius furcidens, Galeoides decadactylus and Cynoglossus senegalensis), four as Vulnerable (B. brevis, Rhexipanchax nimbaensis, Enteromius raimbaulti and Tilapia busumana) and one as Endangered species (Pseudotolithus senegalensis). These categories of species that have a conservation interest according to the IUCN Red List represent respectively 10.26% of the whole population. Fish population of the Aghien Lagoon are divided into seven classes ranging from “low” to “very high” vulnerability, regarding the vulnerability to stress due to fishing pressure.