ECOGENOTOXICOGICAL ASSESSMENTS OF SOME SELECTED FISH SPECIES FROM APODU RESERVOIR, MALETE, NORTH CENTRAL, NIGERIA

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’ influx 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 the kidney of M. deliciosus shows severe changes amidst other species. The cortex in the renal

tissue shows numerous glomeruli and tubules lying back to back and lined by cuboided epithelium
cells. The livers of fsh in the reservoir showed irregular plates of hepatocytes while the gills
showed mild distortion of epithelia lining, cartilage, and lymphatic cells. The flowing of water
alongside agricultural and domestic activities around the reservoir might be attributed to the
micronuclei deformities and histopathological alterations. Proper management of the habitat
quality of the Apodu Reservoir appears necessary.