A Study of Diplostomum Parasites Affecting Oreochromis niloticus in Chepkoilel Fish Farm and Two Dams in Eldoret-Kenya

The Diplostomum parasite completes its life-cycle in fish eating birds, but spends considerable time in the eye vitreous humor of many fresh water fishes. Its infection in fish causes severe ocular pathology, and leads to increased susceptibility to predation. A study on Diplostomum parasites was conducted at Chepkoilel University with an objective of assessing its parasitic indices and effects on O. niloticus. A total of 40 fish were collected from the fish farm and 155 from the dams between November 2010 and January, 2011. Fish were weighed and length measured to ascertain their condition factor. The fish were observed for the Diplostomum parasite to ascertain parasitic indices in the different habitats. The parasite abundance was related to fish size and condition factor to determine parasite’s effect on O. niloticus. Fish were found to have a parasitic prevalence (%) of 100, 84 and 66 in Kerita dam, Kesses dam and Chepkoilel fish farm. Parasite mean intensity was 12, 9 and 14 respectively.The wellbeing of the fish was not compromised by the parasites, as was seen in the correlation between condition factor and parasite abundance. There was a Pearson correlation of P = 0.357, 0.516 and 0.565 in Kerita dam, Kesses dam and Chepkoilel fish farm respectively. The dams and the fish farm did not pose significant difference in the parasitic indices, probably due to their proximity. There was seen equal abundance in both fish sexes, implying no sex preference in infection. Keywords: Diplostomum, Oreochromis niloticus, prevalence, Abundance, Mean intensity, Condition factor