Detection of lethal concentration (LC50) of diazinon in Silver Carp (Hypophthalmicthys molitrix) and Roach (Rutilus rutilus)

Aim of this study was to evaluate the effects of diazinon toxicity (LC50) on silver carp and roach fry for measuring resistnce of these fishes. Roach with an average weight of 7 ± 1 g and silver carp 30 ± 1 g were studied to measuring lethal concentration LC50 at 96 hours. Experiment was used with a completely randomized design in 9 treatments and 3 replications for both silver carp and roach. The results showed LC50in silver carp 3.93 (2. 94-4. 99) mg/l was more than roach 1.71 (1.20-2.23) mg/l that means higher diazinon resistance of silver carp than roach.