Toxicological Effects of Different Concentrations of Hypo Bleach on the Mortality of African Clariid Mud Catfish (Clarias gariepinus) Fingerlings

Aim: The study was aimed at evaluating the mortality and LC50 of Clarias gariepinus exposed to different concentrations of hypo bleach.

Methodology: Thirty (30) fingerlings were used for each aquarium exposed to four (4) different concentrations of the toxicant and the control group. The fingerlings were exposed to 0, 1.20, 1.25, 1.75 and 1.90 mg/l of the bleach and the experiment was done in duplicate. A total of 300 C. gariepinus fingerlings were used throughout the study. The fingerlings were of the same age group, ranging from 9.2 to 10.4 cm in length and 5.5 to 6.5g in weight.

Results: The mortality data trend of fingerlings exposed to different concentrations of the toxicant were dependent on the concentration and exposure duration, with the highest mortality of 96.6% observed in the highest concentration. The 96 hours LC50 value with 95% confidence limit of Clarias gariepinus fingerlings exposed to hypo bleach was 0.19 ± 1.73 mg/l, and was significant with a determination coefficient (r2) of 0.93 at P<0.05. The low LC50 value for the fingerlings exposed to the toxicant showed its high toxicity.

Conclusion: The bleach was highly toxic as shown by its very low LC50 value and are capable of causing mortality to organisms even at low concentration. The toxicity of the toxicant was concentration and exposure duration dependent. Also, several behavioral changes was observed in the fingerlings when exposed to the toxicant. As a result of the observed toxicity of hypo bleach to fingerlings of Clarias gariepinus, more research should be carried out on the hematological and physiological alterations of fingerlings when exposed to bleach.