Toxicity bioassays are often used in aquatic ecotoxicology and the main objective of such test is to determine the lethal concentration of toxicants for aquatic organisms. Hematological indices are used to determine the health status of fish. In this study juvenile Heterobranchus bidorsalis of 32.9- 46.4 cm in length and 251.9-298.7g in weight was exposed to different concentrations of Sodium hypochlorite (0.0, 0.5, 1.0, 1.5, 2.0 ml) for 96hrs to assess its toxicity and investigate the effect of the toxicant on the hematological parameters of the fish. Mortality and pattern of response of fish in all the exposure concentrations increased with duration of exposure. The hematological results showed a decrease in Packed Cell Volume (23.00±2.83- 16.50 ± 2.12%), Hemoglobin (7.65± 0.92 – 5.05± 0.07g/mm3) and RBC (2.55 ±0.35-1.35±0.42) while there was an increase in white blood cell (6.00 ± 2.83± 8.55 ± 7.78 (104/ mm3)). There was no significant difference (P<0.05) in the value of Mean cell hemoglobin concentration, Mean cell volume and Mean corpuscular Hemoglobin concentration. This can be use as an index of toxicity in water to determine the health of an aquatic organism.
Keywords: heamatology, heterobrachus bidorsalis, piscidal, sodium hypochlorite
