AVOIDANCE-BEHAVIOR OF CARP TO PESTICIDES AND DECREASE OF THE AVOIDANCE THRESHOLD BY ADDITION OF SODIUM LAURYL SULFATE

We examined the behavioral avoidance to pesticides using a Y-maze flow-through system. Carp showed avoidance responses to emulsions of benthiocarb, isoprothiolane, and fenitrothion at concentrations higher than 1.7, 6.7 and 490 mu g/l, respectively. These avoidance thresholds were 3 log units, 3 log units and 1 log unit lower than each 48 hr LC(50) for the pesticides, respectively. Fenitrothion was the most ineffective to the avoidance among these three pesticides. The anionic surfactant sodium lauryl sulfate (SLS) was the most effective repellent among tested compounds in carp, and the threshold was 10(-2) mu g/l. The addition of 1% SLS to the concentration series of fenitrothion decreased the avoidance threshold. The threshold for the mixture of fenitrothion and SLS was 1 mu g/l.