Avoidance Responses of Rainbow Trout andUtah Chub to Rotenone

Abstract

Avoidance response to the piscicide rotenone was evaluated in rainbow trout Oncorhynchus mykiss and Utah chub Gila atraria. Each fish species was exposed to 12 separate test formulations that varied in the amount of rotenone present as well as the form of rotenone. Test formulations that contained no rotenone were water, liquid carrier, and inert powder. Formulations that contained rotenone (liquid rotenone, powdered rotenone, and a rotenone-only mixture) were tested at three different concentrations (0.045, 0.075, and 0.15 mg rotenone/L). Only rainbow trout exhibited an avoidance response in this study to the liquid and powdered formulations of rotenone. Presence of the carrier, piperonyl butoxide, in the liquid formulation may be a factor in rainbow trout avoidance of liquid rotenone, since trout avoided the liquid carrier treatment too.