Nounagnon Darius Tossavi^{1, 2,}, Guillaume Koussovi¹, Diane Nathalie Sènami Kpoguè Gangbazo^{1, 3}, Romaric Aizonou¹, Gospel Gandé², Tadjida Bienvenu Zannou², Hyppolite Agadjihouèdé¹

Hepsetus odoe is a widespread fish species in tropical regions. It is usually found close to the banks of rivers where vegetation is very heavy. Like an alone species in the family Hepsetidae, H. odoe is supposed to be more abundant in the lagoons, backwaters, and lakes. Unfortunately, it does not meet this hypothesis in the lake Togbadji. The present study was designed to assess some biological factors that can explain the low abundance of H. odoe including the length-weight relationships and the diversity of parasite that can potentially affect it. From January to April 2024, length-weight relationships (LWR) were estimated for 87 fish caught from Lake Togbadji. The parasite collected were identified and their prevalence was assessed. The b value varied between 2.91 for males to 3.51 for females with a mean value equaling to 3.43 (3.16 – 3.57) for both sexes indicating a positive allometric growth and the condition factor (K) was 2.27 for females and 2.53 for males. A parasitological investigation revealed that 7 individuals of the nematode Philometroides sp. were infecting the fish gills. The prevalence is estimated at 3.44 % and the mean abundance is around 2.33 whereas the mean intensity is very low. Those results should be comforted with the mode of reproduction and the diet of this fish to understand more about its relatively low frequency of capture in the Lake.

Condition factor, Hepsetus odoe, Philometroides sp., positive allometric growth, prevalence