Co-Parasitism And Morphometrics Of Three Clinostomatids (Digenea: Clinostomatidae) In Sarotherodon melanotheron From A Tropical Freshwater Lake

Abstract

In ever competitive environment of nature, evolution of most attributes of an organism - anatomy,physiology, and behaviour are determined by the environment through selection. The same is the microhabitats of Sarotherodon melanotheron where three Clinostomatids; Clinostomum tilapiae, Clinostomum complanatum, and Euclinostomum heterostomum, were recovered from Opi Lake (GPS N06.75275*, E00749104*), were studied from (November 2007– October 2008) using multiple fishing gear techniques; cast nets, hook and line, and seine nets (150 mm – 200 mm), showed signiicant dfference (p < 005) in all other anatomical parts but the distance between oraand ventral suckers. The prevalence was low; (20.8 %) was recorded in C. complanatum, (6.4 %) in E. heterostomum and (21.1 %) in C. tilapiae. But mean intensity was high which was suggestive of heavy parasite burden; C. complanatum (2.7), C. tilapiae (5.8) and E. heterostomum (5.1). In therank-abundance curve for parasite communities C.tilapiae was more abundant than the other twospecies. Differential parasitic implications was due o selection for relatively better adaptiveness tohost’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.Key words: Clinostomum sp, co-parasitism, Morphometrics, E. heterostomum, Opi Lake, Selection