Parasitic incidence in cultured and wild Nile tilapia (Oreochromis niloticus) in Makurdi, Benue State, Nigeria

Parasitic incidence in cultured and wild Nile tilapia (Oreochromis niloticus) in Makurdi, Benue State, Nigeria was investigated by standard parasitological techniques using 305 samples comprising 146 and 159 Oreochromis niloticus randomly purchased from the cultured (Ponds) and wild (Lower River Benue) environments, respectively. Nine (9) parasite species belonging to two (2) species each of crustacean (Argulus spp. and Ergasilus spp.), protozoa (Trichodina spp. and Ichyophthyirius multifilis), cestode (Ligula intestinalis and Bothriocephalus spp.) and a species of monogenea (Cichlidogyrus spp.), digenea (Clinostomum spp.) and nematode (Camallanus spp.) were recovered from the examined fish. All the parasites were present in both environments with the exception of I. multifilis that was recovered from the wild O. niloticus. Out of the 146 and 159 samples of cultured and wild O. niloticus, 81 and 62 samples each were infested with 128 and 93 ectoparasites and endoparasites, respectively. The overall prevalence (55.48%), mean intensity (1.58) and abundance (0.88) were higher for cultured O. niloticus compared to the overall prevalence (38.99%), mean intensity (1.50) and abundance (0.58) recorded for the wild O. niloticus. The prevalence and intensity of infection in most of the parasite species were higher (9.59 and 1.50, 7.53 and 1.36, 2.74 and 1.25, 2.05 and 3.33, 5.48 and 1.88, 2.05 and 2.33, respectively from the cultured environment; 6.92 and 1.45, 6.29 and 1.30, 1.26 and 0.50, 0.63 and 2.00, 2.52 and 1.25, 1.26 and 4.00, 3.14 and 1.60, 1.26 and 2.50, respectively from the wild) in females than the males (7.53 and 1.18, 5.48 and 1.13, 1.37 and 1.50, 1.37 and 3.00, 3.42 and 1.60, 0.68 and 2.00, respectively from the cultured environment; 6.29 and 1.20, 4.40 and 1.29, 0.63 and 3.00, 0.00 and 0.00, 0.00 and 0.00, 0.63 and 3.00, 2.52 and 1.25, 0.00 and 0.00, respectively from the wild). Ectoparasites of cultured and wild O. niloticus were more in the gills (114) compared to the skin (25) while endoparasites of cultured and wild samples of O. niloticus were more in the intestine (48) compared to the stomach (40). Parasite prevalence was higher in the bigger fish samples compared to the smaller ones.