American Research Journal of Agriculture

A study of the icthyofauna resources of the coastal waters of Ondo State of Nigeria conducted for 18 months (June 2011-December, 2012) revealed the presence of 67 finfish species with the clariids(especially Clarias gariepinus and Heterobranchus bidorsalis) and cichlids(especially Oreochromis niloticus and Coptodon zilli) dominating the stock accounting for 42% and 16% respectively. Other predominant families were A high ’Claroitedae’(Chrysichthys nigrodigitatus) with 9.2% contribution, ’Channidae’(Parachanna africana) with 8.7%, Osteoglossidae (Heterotis niloticus) with 7.1%, Gymnarchidae( Gymnarchus niloticus), Mugilidae (Mugil cephalus) and Clupeidae (Ethmalosa fimbriata). Lausanne Index of Abundance was 89.7% while Margalef.s index( a measure of species richness) was 5.18. The Length-weight relationships of these predominant fishes showed negative allometric growth pattern. A high level of heterogeneity of stock was observed as revealed by Simpson Index and Shannon-Weiner Index of General Diversity (H i) which were 0.13 and 0.35 respectively. A lot of similarity in species composition existed as revealed by Evenness Index(E) of 0.20 and Berger-Perker Index of 0.88. There was comparatively higher catches of fish in the dry season than the wet season probably due to reduced water volume which concentrated the fishes for easier catchability. The author recommends the need to protect the existing stock especially the monospecific families like the Osteoglosidae and Gymnarchidae through regular monitoring of the physicochemical parameters of the coastal waters which are highly susceptible to crude oil pollution, Ondo State being a crude oil-producing area. More funds should be committed by the government to researches on population dynamics and biomass estimate of our coastal waters.