Gill Monogeneans Infestation and Condition Factor Assessment of Hemichromis fasciatus (Cichlidae) from the Ebrie Lagoon, Côte d’Ivoire

This study investigated the gill parasitofauna of the cichlid fish Hemichromis fasciatus in sectors III and IV of the Ebrie Lagoon, areas subjected to varying anthropogenic pressures, from February 2019 to January 2020. Using standard parasitological methods, five (5) Monogenean species were identified: Cichlidogyrus falcifer, C. sanseoi, C. longicirrus, Onchobdella voltensis, and O. bopeleti. Spatial analysis revealed higher parasite infestations (P = 96.12%; IM = 26.22±0.2) in fish from sector III, which was characterized by lower oxygen levels (2.5 g/l) and reduced water transparency, compared to sector IV. Additionally, host sex significantly influenced parasitic burden. Condition factor assessments showed that infested fish had poorer body condition (K = 0.48±0.2 g/cm3) than non-infested individuals (K = 1.6±0.2 g/cm3), highlighting the detrimental effects of parasitic infections on host health. These findings emphasize the role of environmental and biological factors in shaping parasite dynamics in lagoon ecosystems.