Copyright © 2019 by De La Salle University Manila Journal of Science 11 (2018), pp. 1-14 ECOGENOTOXICOGICAL ASSESSMENTS OF SOME SELECTED FISH SPECIES FROM APODU RESERVOIR, MALETE, NORTH CENTRAL, NIGERIA Abass T. Anifowoshe, 1* Segun O. Oladipo, 2,5 Olubukola A. Owolodun, 1 Monica K. Akinseye, 3 Temitope F. Olafmihan, 4 Abdulmalik G. Sidiq, 1 Aishat A. Muhammed, 1 Titus A. Asa, 1 Moshood K. Mustapha 5 1 Cell Biology and Genetics Unit, Department of Zoology, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria 2 Zoology Unit, Department of Biosciences and Biotechnology, Kwara State University, Malete, Nigeria 3 Department of Biology, Adeyemi College of Education, Ondo, Ondo, Nigeria 4 Ecology and Environmental Biology Unit, Department of Zoology, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria 5 Fisheries and Hydrobiology Unit, Department of Zoology, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria *Corresponding author email:anifowoshe.at@unilorin.edu.ng or abassgenetics@gmail.com ABSTRACT Increased agricultural and domestic activities around and within aquatic ecosystem could pose serious threats to the habitat quality and ichthyofauna diversity. Nigeria is a country notable for the alarming rate of water pollution. On the other hand, increased human populace around the Apodu Reservoir has led to an intensifying rate of pollutants’ infux into the water body. To date, there is limited information on the habitat quality and associated genotoxic effects of pollutants on physiology of fsh communities from the Apodu Reservoir. To infer these, water samples were collected randomly, and fsh species were assayed for genotoxicity using micronucleus and histological assays. In this study, the in situ genotoxic potential of different species of fsh (Clarias gariepinus, Synodontis gambiensis, Saraetherodon galilaeus, and Protopterus annectins) present in the Apodu Reservoir on the somatic cells using MN assay was evaluated. The kidney, liver, and gills of the fshes (Clarias gariepinus, Auchenoglanis occidentalis, Tilapia mariae, Mormyrops deliciosus, Saraetherodon galilaeus, and Hemichromis fasciatus) found in the reservoir and the physicochemical parameters of both the reservoir and borehole water (negative control) were also examined. The physico-chemical and heavy metals analyzed (Ca > Ni > Cl > P > Mg > Fe > Zn > Mn > Cu > Pb = Cr) were below the proposed limit by standard organizations. The different species of fsh thriving in the reservoir show varying level of micronuclei and nuclear abnormalities in the order (S. gambiensis > C. gariepinus > P. annectins > S. galilaeus), and the histopathological assessment of the kidney, liver, and gills amidst the fsh shows mild alterations when compared to the control fsh. The histopathology of