Effect of age and weight-specific respiration rate on toxicity of esfenvalerate pulse-exposure to the Australian crimson-spotted rainbow fish (Melanotaenia fluviatilis)

The acute toxicity of a 1-h pulse-exposure with the synthetic pyrethroid pesticide, esfenvalerate, to Australian crimson-spotted rainbow fish (Melanotaenia fluviatilis) of different ages was measured. The effects of esfenvalerate were measured on embryos 1, 2, 4, 8, 24, 72, and 144 h post-fertilisation, and on larvae 50, and weight-specific respiration rate. The eggs of the rainbow fish were not sensitive to esfenvalerate, although the pesticide was highly toxic to larvae less than 1 week old. The mean (s.e.) 96 h LC₅₀'s following a 1-h pulse-exposure to esfenvalerate were 2.32 (0.70), 1.07 (0.26), 28.11 (14.46), 33.42 (10.21), 48.04 (13.34) and 3960 (157) μg 1^-1 for rainbow fish