Gastrointestinal parasite prevalence of cultured Clarias gariepinus in Port Harcourt, Rivers State, Nigeria

Fish parasites are a key constraint to the production, sustainability and economic viability of aquaculture practices in Nigeria. Still, little has been documented on fish parasites and their associated risk factors. This study determined the prevalence of gastrointestinal parasites of Clarias gariepinus. One hundred and twenty (120) fish of different age groups in lengths, weights and sexes were randomly sampled from 3 fish farms (Station 1, Station 2 and Station 3) and examined for parasites. Of the 120 fishes examined, 83 (69.10%) were infected. Station 2 (33, 27.50%) recorded the highest overall prevalence percentage of parasitic fauna, followed by Station 1 (26, 21.60%) and Station 3 (24, 20%) the least. Sex-related prevalence of gastrointestinal parasites recorded a higher value (62, 51.59%) in males compared to female fishes (21, 16.0%). Age of fish based on lengths and weights indicated that smaller fishes harboured more parasites than bigger fishes. Observed parasites were nematodes, protozoan, trematodes and cestodes. Nematodes (33, 27.50%) recorded the highest abundance. In conclusion, smaller fishes were more infected than bigger ones in this study, suggesting best management practices to mitigate parasitic infection, especially in the smaller fishes.