IOSR Journal of Pharmacy and Biological Sciences (IOSR-JPBS) e-ISSN: 2278-3008, p-ISSN:2319-7676. Volume 9, Issue 3 Ver. V (May -Jun. 2014), PP 05-12 www.iosrjournals.org www.iosrjournals.org 5 | Page Multiple Infections of Helminths in the Stomach and Intestine of Clarias Gariepinus (Burchell, 1822) In Oba Reservoir, Oyo State, Nigeria. Ajala, Olasunmibo Olumuyiwa 1 and Fawole, O. Olatunde 2 . 1,2 Department of Pure and Applied Biology, LadokeAkintola University of Technology, Ogbomoso, Nigeria. Abstract:The study was carried out in Oba reservoir,( 8° 3"to 8° 12"N and 4° 6"to 4° 12"E in Oyo state, Nigeria.) between August 2011 and November 2013. A total of 246 live fishes (Clarias gariepinus),purchased from local fishermen were examined. In the laboratory, morphometric parameters were measured, sexes determined and fishes were dissected to separate the alimentary system. Parasites recovered were identified and counted; data were subjected to statistical analyses. Parasites recovered were Procamallanus laevionchus, Paracamallanus cyathopharynx (Nematodes.), Anomotaenia sp., Monobothrium sp., Polyonchobothrium clariae. (Cestodes) and Neoechinorynchus rutili (Acanthocephalan).Using non parametric (NPar), Kolmogorov-Smirnov (K-S) test, infection was significant (p = 0.05) within seasons, and females were more infected than males. Prevalence was 46.34%. Monobothrium sp. had the highest range of infection (0 - 32) and intensity (21.98+2.08) while Anomotaenia sp. had the least (0 – 1) and (1.00+0.01) respectively. Six parasites were found in the intestine, while four were in the stomach. Fishes of small sizes (< 10cm) and small weight (< 20g) were not infected; there was high prevalence in medium and large sized fish and a direct linear relationship exist between length and intensity. Body weight was significant (K-S; p = 0.05) in relation to infection and sex. Multiple infections were common, which showed a positive correlation (Spearman) between most of the parasites except Anomotaenia sp. which showed negative correlation with P. clariae. Key words: Clarias gariepinus, Morphometric, Parasite, Prevalence. I. Introduction The study of parasites of freshwater fishes in Africa is sporadic and inadequate considering the fish wealth of the continent. Studies in Africa vary considerably from area to area and the parasites are mostly mentioned, as part of the fulfillment of the biology of the host fish species. A concise update of the parasitic diseases of fish in Africa, which described the concurrence and geographical distribution, life cycles, pathology, epizootology and control of the parasites, was published by [1].A checklist of the helminthes parasites of African freshwater fishes was also published [2]. Numerous parasites were associated with Tilapia zilli, Clarias anguillaris and Clarias gariepinus during the study of the biology of the fish species in their natural environments[3], [4] and [5]. From an aquaculture perspective, it is noteworthy that disease and parasite infestation have been poorly studied in Africa due to the low level intensity of aquaculture in the region. At present, the paucity of research in fish diseases in Africa is not seen as a factor that will negatively impact on aquaculture development and as such is not a target research area. The emanating need to culture fishes for protein consumption for the teeming rapidly growing populations in the developing countries like Nigeria have made it necessary to intensify studies on the parasite fauna of the African freshwater fishes, [6]. Fish parasites are important because they affect fish production particularly under culture systems, by decreasing their yield, aesthetic value, marketability, palatability and reproductive potential [7],[8], and if left uncurtailed, may lead to mass mortality of fish, or in some cases, emergence of zoonotic species. They are therefore studied with a view to understanding their population biology and elucidate their life cycles in order to develop an efficient approach of controlling them [9]. The occurrences of helminth parasites in fishes have been studied extensively in various water bodies in Nigeria, with most of the work done primarily from the morphologic and morphometric descriptions, but factors that may limit the ability of parasites to co-exist in multiple infections in a host fish species had in most studies been neglected. This study is focused on the parasite species diversity, the level of co- existence/concurrent infection between them, the factors that might limit this relationship and the effects it has on C. gariepinus.