Gill parasitic copepods infestation on the carp Coptodon guineensis (Cichlidae) from Ayame 2 man-made lake (Côte d’Ivoire)

Abstract

Coptodon guineensis is a freshwater Cichlid species native to West Africa, commonly exploited for local consumption. In the Ayame 2 lake, this species faces considerable parasitic pressure, particularly from gill-infesting parasitic Copepods, which may compromise its health and physiological condition. Between January and July 2023, a total of 203 specimens of C. guineensis were sampled monthly from the lake. Parasitic Copepods were collected following standard parasitological procedures, focusing on the examination of fish gills. Three Copepod species were identified: Ergasilus latus, Paraergasilus lagoonaris, and Lamproglena monodi. Among these, E. latus was the most prevalence (31.52%), with the highest mean intensity (18.23 parasites per infected host) and abundance (12.34), indicating its dominant parasitic impact. A marked seasonal variation was observed, with significantly higher prevalence and intensity during the rainy season for example, E. latus peaked at 48.15% in June. Males were generally more heavily infested than females, except for L. monodi, which was more frequent in females. Parasitic infection significantly affected the fish's body condition infected individuals had a mean condition factor of 0.4±0.01 compared to 0.75±0.1 in uninfected fish. This physiological decline was also sex-dependent, with infected males being more affected than females. This study highlights the high parasitic pressure from gill Copepods on C. guineensis in the Ayame 2 lake, modulated by season and host sex, with measurable impacts on host condition underscoring the need for ecological monitoring and fish health management in this aquatic system.