Effects of three pesticides on respiration, coughing, and heart rates of rainbow trout (Salmo gairdneri Richardson)

Abstract

Short-term, sublethal changes in respiration, heart, and coughing rates in juvenile rainbow trout (1–1.5 years) exposed to the organochlorine pesticides p,p′-DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and HEOD (dieldrin) and the methyl carbamate insecticide carbaryl (1-naphthyl N-methyl carbamate) were monitored at 13 ± 2 °C to investigate the effects of these pesticides on fish in fresh water. Sublethal responses to carbaryl and HEOD on physiological parameters were difficult to measure because dosages required to elicit them resulted in 30% to 60% mortality. DDT in various concentrations gave graded sublethal responses, and it is suggested that the coughing response in particular might be useful as a water-quality index. The DDT threshold for the coughing response was between 52 and 140 parts per billion.