Determination of lethal concentration (LC10-90) values of Deltamethrin and Fenvalerate and their effects on clinical signs and behavioral responses in Zagros pupfish, Aphanius vladykovi (Coad, 1988)

Synthetic pyrethroid insecticides are widely used in place of organochlorine, organophosphorus insecticides and carbamates to control various types of pests and are among the most potent insecticides known. Due to the extensive application of deltamethrin and fenvalerate in the agricultural lands of the Chaharmahal and Bakhtiari province in central Iran, this investigation was conducted to determine LC50, NOEC, MAC and LOEC of these pyrethroid insecticides and their effects on behavioral responses and clinical signs of Zagros pupfish, Aphanius vladykovi. For this, groups of seven A. vladykovi in three replicates were exposed to different concentrations of deltamethrin (EC 2.5%) and fenvalerate (EC 20%) for 96 h within the 20 L glass aquaria and cumulative mortality of fish was calculated in 24-h interval. During experiments reaction and behavior of the fish to toxin were observed carefully. The 96h LC50, NOEC, LOEC, MAC values of deltamethrin for A. vladykovi were estimated at 0.015, 0.0001, 0.0005 and 0.0002 ppb, respectively. The 96h LC50, NOEC, LOEC, MAC values of fenvalerate for Zagros pupfish were estimated at 0.021, 0.0005, 0.001 and 0.0007 ppb, respectively. First changes in behavior were observed 15min after exposure to the three highest deltamethrin concentrations (0.01, 0.1, and 1ppb). The changes in behavioral responses started in the 3 h after dosing of fenvalerate (0.01, 0.1, 1 and 10 ppb). Based on the results, deltamethrin and fenvalerate were classified as super toxic pesticide for Zagros pupfish and this fact should be taken into consideration when these insecticides were used in agriculture. Biological methods could be used for controlling pets instead of pesticides in order to protect this valuable species.