Diversity, Relative Abundance and Ecological Indices of Fish Species in Tongon Lake, Northern Côte d’Ivoire
Awa Ndiaye *
Université Peleforo Gon Coulibaly, Unité de Formation et de Recherche des Sciences Biologiques, Laboratoire Environnement Climat Santé Ingénierie et Développement Durable, BP 1328 Korhogo, Côte d'Ivoire.
Tiehoua Kone
Université Peleforo Gon Coulibaly, Unité de Formation et de Recherche des Sciences Biologiques, Laboratoire Environnement Climat Santé Ingénierie et Développement Durable, BP 1328 Korhogo, Côte d'Ivoire.
Kobenan Mathieu Kra
Université Peleforo Gon Coulibaly, Unité de Formation et de Recherche des Sciences Biologiques, Laboratoire Environnement Climat Santé Ingénierie et Développement Durable, BP 1328 Korhogo, Côte d'Ivoire.
Kouassi Brahiman Kien
Université Peleforo Gon Coulibaly, Unité de Formation et de Recherche des Sciences Biologiques, Laboratoire Environnement Climat Santé Ingénierie et Développement Durable, BP 1328 Korhogo, Côte d'Ivoire.
Yao Nicolas Amon
Université Peleforo Gon Coulibaly, Unité de Formation et de Recherche des Sciences Biologiques, Laboratoire Environnement Climat Santé Ingénierie et Développement Durable, BP 1328 Korhogo, Côte d'Ivoire.
Dramane Diomande
Université Nangui Abrogoua, Unité de Formation et de Recherche des Sciences et Gestion de l’Environnement, Laboratoire d’Environnement et de Biologie Aquatique, 02 BP 801 Abidjan 02, Côte d’Ivoire.
*Author to whom correspondence should be addressed.
Abstract
Dam lakes in the Korhogo department were originally constructed for agriculture and livestock production, but now present significant potential for fisheries development. Several studies have been conducted to update knowledge on fish fauna in some dam lakes in northern Côte d’Ivoire. However, data on the ichthyofauna of Lake Tongon in the Korhogo department remain scarce. Therefore, this study aims to assess the fish diversity of Lake Tongon. The sampling, which took place from December 2024 to July 2025, involved compiling an inventory of the various fish species caught in small-scale fisheries. Species richness, relative species abundance, frequency of occurrence, Shannon-Weaver diversity Index and Pielou’s evenness index were the parameters determined in this study. Analysis of the data collected identified 33 fish species, divided into 17 genera, 11 families and 7 orders. The most diverse families were the Cichlidae (9 species), the Cyprinidae (4 species) and the Mormyridae (4 species). The frequency of occurrence values determined made it possible to identify 16 common species, 6 occasional species and 11 rare species. The species-specific relative abundance indicates that the fish community in this lake is dominated by the following species: Hemichromis fasciatus (25.73%), Coptodon zillii (12.96%), Coptodon hybrid (C. guineensis × C. zillii) (8.57%), Chrysichthys nigrodigitatus (7.56%), Sarotherodon galilaeus (7.17%). The values for the Shannon-Weaver diversity Index and the evenness index, at 0.78 and 0.44, respectively, indicate a species-poor population and a disturbed ecological state in this lake.
Keywords: Fish species, diversity, seasonal abundance, Pielou evenness, small-scale fisheries, Tongon lake.