TOXICITY EVALUATION AND OXYGEN CONSUMPTION STUDIES ON THE FISH CTENOPHARYNGODON IDELLA EXPOSED TO λ-CYHALOTHRIN 5% EC

The natural physiological functioning of an organism gets disturbed on exposure to toxicant stress. Toxicants affect first at cellular levels. It ultimately causes physiological, pathological, and biochemical alterations in an organism. Present study λ-Cyhalothrin of 5% EC formulation pyrethroid was used static renewal bioassay to evaluate 96 h LC₅₀ in the freshwater fish Ctenopharyngodon idella and it was determined at 0.026 mg/l. The exposed fish Ctenopharyngodon idella showed irregular, erratic, and darting swimming movements, rapid opercular movements, gulping of air at the surface, hyperexcitability, increased mucus secretion, loss of equilibrium and hitting to the sidewalls of the test tank and finally sinking to the bottom. 1/10^th of the 96 h LC₅₀ was taken as sub-lethal (0.0026 mg/l) concentration for oxygen consumption studies, and it was carried out for a period of 24 h, at regular intervals of 2 h. In the lethal and sub-lethal concentration, the rates of oxygen consumption were increased during the initial time of exposures, i.e., 1 to 6 h after that it was suddenly falling gradually up to 24 h, and the control fish oxygen consumption also fell 0 h to 24 h.