Acute toxicity of two organophosphorus pesticides to the early-life stage of flathead grey mullet, Mugil cephalus (Linnaeus, 1758)

The acute toxicity (96 h LC₅₀) of two organophosphorus pesticides (OPs), chlorpyrifos (CPF) and dimethoate (DMT) to the early-life stage (fry) of flathead grey mullet, Mugil cephalus (total length, 22±2 mm, wet weight, 285±4 mg) was evaluated. M. cephalus were exposed to concentrations of CPF (2, 4, 6, 8, and 10 μg/L) and DMT (300, 750, 1500, 3000 and 4500 μg/L) for 96 h. Values of 96 h LC₅₀ indicated that CPF (3.45 μg/L; 95 % confidence limits, lower = 2.77 and upper = 4.06 μg/L) was found to be highly toxic to M. cephalus fry compared to DMT (854.10 μg/L; 95 % confidence limits, lower = 558.23 and upper = 1176.77 μg/L). Data obtained during the present study would be helpful in monitoring OP pollution in coastal waters with M. cephalus as key bioindicator species.