Carbamate pesticide carbaryl effect on population growth of freshwater rotifer Brachionus calyciflorus

Rotifers is frequently used as indicator test animals of water pollutants due to their sensitivity and ecological importance. In present study, population response of rotifer B. calyciflorus to six different concentrations of carbaryl (0, 1, 10, 100, 200 and 400 µg/l(parts per billion)) with three replicates per concentration was studied for 6 days. Rotifer density and specific growth rate were calculated daily in the control and treatments containing carbaryl. Result showed that, rotifer population growth decreased significantly (p< 0.05) with increasing carbaryl concentration in the medium. The maximum density in six day belongs to control (49.15± 0.05 ind/ml) and minimum density belongs to treatments containing concentration of 400 µg/l carbaryl (6.28± 0/1 ind/ml). Also, the rotifer specific growth rate decreased significantly (p< 0.05) (from 0.71± 0/006 in control group to 0.37± 0/003 in concentration of 400 µg/l) with increasing concentration of this pesticide. The results showed that the pesticide carbaryl even at very low concentrations can highly affect the population rotifer B. calyciflorus.