Seasonal variation of ichthyological diversity in catches of trawlers operating in the Exclusive Economic Zone of Côte d'Ivoire

A study on the seasonal evolution of the diversity of ichthyofauna from trawler catches was conducted in Ivorian marine waters. Monthly sampling carried out from August 2021 to July 2022 at the rate of four samples per month when the trawlers landed and the analyses carried out in the laboratory made it possible to count 1047 fish specimens during the long cold season and 1036 specimens during the long warm season. Individuals from the first season are divided into 9 orders, 32 families and 68 species; those from the warm season are divided into 10 orders, 23 families and 39 species. During the short warm season, 507 specimens (5 orders, 19 families and 34 species) were recorded. The smallest number of fish was recorded during the short cold season (381 specimens divided into 5 orders, 20 families and 30 species). The Carangidae family is the most diverse in all seasons. In terms of abundance, Haemulidae dominate the fish population during the short seasons, while Ophidiidae are more abundant in the long warm season, followed by Polynemidae in the long cold season. Analysis of diversity indices (Shannon and equitability) did not reveal any significant differences (ANOVA; p > 0.05), reflecting a good distribution of species. The Bray-Curtis similarity index highlights a similarity between the fish population of the short warm and cold seasons. These results provide essential information for the sustainable management of fishery resources in Côte d'Ivoire.