Automotive gas oil effects on performance of <i>Clarias gariepinus</i>: Implications of oil spills in the Niger Delta, Nigeria

Abstract

Water pollution, which is sometimes caused by the spilling of crude oil or commercial petroleum fuels (CPFs), is a major environmental  problem that causes toxic effects in aquatic ecosystems. Hence, the effects of varied concentrations of Automotive Gas Oil (AGO) on  aquatic species (Clarias gariepinus) was investigated. A total of 250 juveniles of C. gariepinus (mean weight 3.3g) were procured and used  for the experiment. Fish samples were divided into five groups and assigned to different AGO concentrations (0mg/l (control), 5mg/ l, 10mg/l, 15mg/l, and 20mg/l) in a laboratory condition for a period of 14 days. Each treatment was split into 3 replicates, containing 14  juveniles of C. gariepinus each. A 20-liter capacity holding tanks filled with de–chlorinated bore hole water was used for the experiment.  The effects of exposure to AGO pollution levels on proximate composition, and freshness of test organisms were investigated following  standard procedure. Data collected were subjected to analysis of variance (ANOVA) and test of significance was by Duncan Multiple  Range Test. From the results there was no mortality recorded for fish exposed to all treatments. However, AGO pollution levels  significantly affected (p>0.05) proximate composition, and fish freshness. There were no significant differences (p<0.05) in freshness of fish among the control group, 5mg/l and 10mg/l AGO levels. Moisture (5.88-7.95%) and fat (11.09- 21.25%) contents, energy  (282.73-424.58Kcal) and carbohydrate (16.03-28.40%) levels of fish decreased with increase in AGO pollution level. The study concluded  that C. gariepinus is a good bio-indicator for AGO polluted aquatic environment. The results of the present study implied that fish  populations in Niger Delta polluted waters are negatively impacted in terms of quality and quantity. Measures to stop pollution of water  bodies by AGO and other refined crude products are recommended by the study.