Co-infection and morphometrics of three clinostomatids (Digenea: Clinostomatidae) in Tilapia guinensis Bleeker, 1862 from Opi lake, Nigeria

Abstract

Co-infection and morphometrics of helminth parasites of Tilapia guinensis in Opi Lake (GPS N06.75275*, E007.49104*), were studied from (Nov 2007– Oct 2008) using multiple fishing gear techniques; cast nets, hook and line, and seine nets (150 mm – 200 mm). The parasites recovered were C. tilapiae, C. complanatum and E. heterostomum. The prevalence was low, indicative of parasitic infection in the wild. Prevalence of (33.9 %) was recorded in C. complanatum, (7.2 %) in E. heterostomum and (12.6 %) in C. tilapiae. But high mean intensity was suggestive of heavy parasite burden; C. complanatum (4.8), C. tilapiae (2.8), and E. heterostomum (5.1). Morphometrics of the parasites showed no significance difference in the distance between oral and ventral suckers. However, they differed in all other parts significantly (p < 0.05). In the rank-abundance curve for parasite communities, C. complanatum was most abundant (pi 0.63). Differential parasitic effects were due to selection for relatively better adaptiveness to host’s microhabitats, more population size, better host location, and larger body size. Consequently, this resulted in a trade-off between larger morphometric parts and population size among the parasites