To assess the impact of Cypermethrin (10 EC) on Natural fish food (zooplankton)

Agricultural pyrethroid insecticide, particularly cypermethrin, is frequently used in commercial carp aquaculture ponds to control aquatic bugs. These pyrethroids are extremely toxic to a broad spectrum of aquatic creatures. The aim of this study was to investigate the effect of pyrethroid insecticide cypermethrin (10 EC) on the survivability rate of Natural fish food (zooplankton). The eight different concentrations of cypermethrin (10 EC) were used 0.4, 14, 2.4, 3.4, 4.4, 5.4, 6.4, 7.4 µl/l to investigate the cypermethrin toxicity. The stock solution was prepared by dissolving suitable amount of cypermethrin in one litre of diluent water. The test concentrations of dilute solution of cypermethrin were expressed in microliter per litre (µl/l). At a concentration of 1.4 µl/l of cypermethrin, the survivability rate was 82 % at the end of the 8th hour and 78% at the end of the 10th hour. At the concentrations of 6.4 µl/l and 7.4 µl/l, 60% and 50% survivability of zooplankton was reported by the end of 8th and 10th hour, respectively. The LC50 values were recorded between 2.43 and 23.98 for different time durations.