Microbial survey of fish ponds and mineral composition of <em>Clarias gariepinus</em> in Ilorin metropolis

Abstract

This work reports on the microbial composition of stagnant fish ponds and mineral & metal composition of Clarias gariepinus from the fish ponds in Ilorin, Kwara State, Nigeria. The fishes apparently thrived well in the fish ponds. Microbiological analysis of the different fish ponds as well as the mineral composition of the fish samples were carried out. Results revealed bacterial counts ranging from 1.0-2.0 x 10⁴ cfu/ml of the stagnant ponds water, 9.0 x 10³-1.2 x 10⁴cfu/ml of water from fish ponds whose water was changed daily and 3-10 x 10³ cfu/ml of water from borehole. Total coliform count ranged from 6 x 10³-1.5 x 10⁴ cfu/ml of the stagnant pond water, 6-18 cfu/100ml of water from ponds whose water was changed daily and 1-6 cfu/100ml of water from borehole. Pathogenic fungi (Aspergillus niger) was isolated from the stagnant pond water while none was isolated from fish ponds whose water was changed daily. Faecal coliforms were not isolated from any of the water samples. Analysis of the mineral composition of the fish samples showed that phosphorus and potassium were highest in fish from ponds that the water is changed daily. Metal concentration in the fish showed that Cd ,Pb, Co and Cr did not exceed the maximum acceptable concentration for humans. Proper cooking before consumption of fish is therefore advocated to prevent transmission of the bacteria and fungi to the consumers.

Keywords: Clarias gariepinus, microbial survey, mineral composition, Ilorin, Nigeria