Effect of Oil Spillage on Catfish (Clarias gariepinus) in the Aquatic Water Body Nigeria

Abstract

The scarcity of catfish (Clarias gariepinus) to stock existing fishpond in Nigeria has been attributed to cannibalism and nutritional problem among other factors. The incessant occurrence of oil spill accidents from the Nigeria oil industries has constantly degraded the aquatic environments where juveniles abound thereby depleting the already poor sources of supply. This study was undertaken to assess the effect of crude oil and some petroleum products on the mortality rate of C. gariepinus and also to facilitate inferential deductions that will enhance effective aquatic environmental management. Ninety healthy bred juveniles of catfish (C. gariepinus) were randomly placed in 15 plastic baths and were exposed to different concentrations of oil. The results showed that the feeding behavior and swimming performances of fish were reduced after 24 h of the addition of the various oil pollutants. Mortality of juveniles in the oiled basins increased as the hours exposure increased (i.e 24, 48, 72 and 96 h). Crude oil and petroleum fractions cause blockage of atmospheric oxygen from dissolving in water thereby limiting the supply of oxygen to fish juveniles resulting to incidence of excretory waste products (carbon dioxide and ammonia) in the ambient water environment. Recovery was not immediate in the treated basin while surviving juveniles in the control basins grew up to post-juveniles after 90 days. There were significant differences (P<0.01 and P<0.05) in the effect of crude oil and the petroleum products on the mortality rate of C. gariepinus when exposed to oil pollutants at 1.25 ml.