Evaluation of Lethality Effect and Morphometric Indices Alterations in Clarias gariepinus Exposed to Shapshooter

Abstract

Aim: The present study evaluated the lethality effect and morphometric indices alterations in Clarias gariepinus exposed to sharpshooter. Study Design: This study employed experimental design and statistical analysis of data and interpretation. Place and Duration of Studies: This study was carried out in Applied Biology Special Laboratory Agbani, Enugu State University of Science and Technology Enugu State (ESUT), Enugu State Nigeria. It lasted thirty days. Methodology: Physicochemical parameters of the sharpshooter mixed water was analysed using standard methods. The 96h LC50 value estimated by Probit analysis was 0.03 mgl-1. The sublethal concentrations of sharpshooter based on the 96h LC50 is 1/10th of 96h LC50, 0.01 mg/L, and 1/5th of 96h LC50 0.03 mg/L. The morphometric indices especially hepatosomatic index (HSI) and condition factor (K) were also estimated using standard methods. Results: The physico-chemical parameters of the test water showed no significant difference (p > 0.05) compared with the control. Mortality caused by the pesticide increased with increase in concentration. Mortality rate increased with increase in concentration with the highest recorded 0.05 mgl-1 at 96h (90% (27 fishes out of 30 fishes). The safe levels determined for the pesticide showed some variations. Whereas there was no significant difference (p > 0.05) between 0.01 mg/L treatments and control, 0.03 mg/L caused a significant decrease (p < 0.05) in HIS compared with control. Similarly, sharpshooter treatment caused a duration dependent significant increase (p < 0.05) at day 15. The treatment with sharpshooter caused concentration and duration significant increase (p < 0.05) in condition factor (K) compared with control. Conclusion: This study has demonstrated that sharpshooter is toxic to Clarias gariepinus even at low concentrations. Therefore, the use of this pesticide in the environment especially farm lands and areas close to aquatic environment should be applied with caution to avoid the risk of contamination.