Effects of Toluene on Some Physicochemical Parameters of The Test Water, Reproductive, Hatching Success and Growth Performance of Clarias gariepinus   (Burshell, 1822)

The effects of toluene on the reproductive, hatching success and growth performance of Clarias gariepinus was investigated. The study lasted for 12 weeks with 6 varied concentrations including the control. The concentrations were 0.001%, 0.0015%, 0.002%, 0.0025%, 0.003% and 0.00 which served as the control. During the study, some physicochemical parameters (pH, Temperature, dissolved oxygen and conductivity) were monitored. The results showed that there were variation in these parameters but the differences in mean physicochemical parameters were not statistically significant (P > 0.05) apart from conductivity which had a significant differences in mean values (P < 0.05). The control (0.00%) recorded the least mean conductivity value of 8.0±0.00 while the 0.001% concentration had the highest with 18.66±0.00 uS/cm. Retarded growth was observed in the study when comparing the specific growth rate of the control (SGR = 6.86%) with those of the exposed groups (4.56, 4.48, 4.47, 4.36 and 4.36) being values for 0.001%. 0.0015%, 0.002%, 0.0025% and 0.003% respectively. The difference between the SGR of the control when compared with the treated groups was statistically significant (P < 0.05). Reproductive success analysis showed a decrease in hatching success across the concentrations and high mortality of eggs with increased concentration. The control had 36.6% hatching success, while 0.001% and 0.003% concentrations had 36.1% and 5.0% respectively. It can be concluded that toluene has an adverse effects on the reproductive, hatchability success and growth performance of C. gariepinus. Therefore, it should be used with restraint and discharges containing toluene and other hydrocarbon compound should be properly treated before released into the environment.