Incidence of parasitic nematodes in Parachanna obscura (Gunther, 1861) in the Sô River in southern Benin

Abstract

This study aims at evaluating the nematode incident on Parachanna obscura in the waters of South Benin. Six hundred and ninety (690) specimens of Parachanna obscura of various sizes were sampled at three sites along the Sô River: Tota, Ahomey, and Ganvié, from November 2018 to October 2019. Three species of nematodes to be known: Spirocamallanus spiralis, Paracamallanus cyathophrynx, Camallanus sp were recorded, and an overall infestation rate of 54.49% to the different nematode species was obtained, with very significant differences (P = 0.000) between the prevalences of these nematode species and this from one site to another. Infestation with different nematode species was possible in all seasons of the year (P=0,000). It is much higher in December (87.71%) and lower in March (21.18%) and varies according to the size classes and weight of the fish. Medium size and medium weight specimens are more infested than others. Although males are more exposed than females, the different infestation rates by sex again show that the sex of the host fish did not influence the distribution of parasite prevalence