The effects of temperature, salinity and a simulated tidal cycle on the toxicity of fenitrothion to Callinectes sapidus.

The 96 hr LC50 for Callinectes sapidus exposed to fenitrothion at 22 degrees C and a salinity of 34 ppt (parts per thousand) was estimated to be 8.6 micrograms/l with a 95% confidence interval of 7.4-9.9 micrograms/l. Acute toxicity was shown to increase with increasing temperature as well as increasing salinity. Exposure of Callinectes to a simulated tidal cycle of 17 ppt salinity change at 6 hr intervals increased the acute toxicity of fenitrothion to Callinectes. The autotomization response in Callinectes was shown to be affected at subacute exposure levels as low as 0.1 microgram/l.