Abstract
Studies on the effect of Mardo (newly introduced orgarophosphate pesticide) on changes in haematological indices were made in a fresh water fish, Mystus vittatus (Bloch). The mean value of RBC counts, mean erythrocyte diameter, Hb content, packed cell volume (PCV), MCH, MCHC and total 3 leucocyte counts in control group of fishes were – 1.913±0.002 (million cells/mm of blood), 37.65±0.125 2 µm , 8.105±0.045 g/100ml, 13.7±0.344%, 45.605±0.093 pg, 56.405±0.004% and 24.0±0.127 3 thousands/mm . The treatment of sub lethal dosages (0.15, 0.18, 0.20 and 0.215 mg/l) of Mardo for 96 hr brought statistically significant decrease in most of the above noted indices as compared to control. The reason for such changes has been discussed in this paper.