Metazoan parasite fauna of Clarias gariepinus (Clariidae) and Oreochromis niloticus (Cichlidae), two fishes from whédos around the upper delta of Ouémé river in southern Benin

Abstract

An intensive parasite survey was conducted in 2016 to get more information the occurrence of parasite fauna, its distribution and diversity in the commercial cultured fish species, Clarias gariepinus and Oreochromis niloticus, from whédos of Ouémé upper delta in south Benin. Sampling was carried out in the three communes of the upper delta of Ouémé (Bonou, Ouinhi, Zagnanado). Thirty artificial whedos were selected at the rate of ten per commune. A total of 757 fish (417 C. gariepinus and 340 O. niloticus) were collected during flood and recession periods of Ouémé river and were examined for parasites using routine parasitological technics.The survey yielded 11 parasite taxon: 6 from Oreochromis niloticus and seven from Clarias gariepinus. Two taxon, Clinostomum sp. and Gryporhynchidae, were both parasites of the two fish hosts. O. niloticus was dominated by free-living stage-transmitted parasites, whereas both trophically and free-living stage-transmitted parasites were represented in C. gariepinus in relatively high intensities. Gills were generally less parasitized, but heavily by monogeneans. The gut was highly parasitized principally by nematodes and trematodes. Generally, the occurrence and diversity of parasites in these fish species highlight the likelihood of disease outbreak in the proposed aquaculture systems. This calls up to raise awareness in fish health management among potential farmers, service providers and researchers.