Behavioral and olfactory responses to prochloraz, bentazone, and nicosulfuron-contaminated flows in goldfish

The immediate behavioral responses of goldfish (Carassius auratus) to pesti cide-contaminated flows were recorded in a countercurrent olfactometer. In addition, electro-olfactograms were recorded from the epithelial surface of the olfactory rosette as a preliminary check for the. olfactory sensitivit y of the fish to the pesticides tested. All tests were run on prochloraz (i midazole fungicide), bentazone (diazine herbicide), and nicosulfuron (sulfo nylurea herbicide). Behavioral effects were assessed, at four concentration s (10 mug/L, 100 mug/L, 1 mg/L, 10 mg/L), on endpoints related to swimming pattern (preference-avoidance responses, burst swimming reactions), comfort activities (buccal movements, feeding attempts), and social relations (ant agonistic acts, grouping). The behavior of the fish appeared particularly s ensitive to prochloraz exposure. As a whole, prochloraz-contaminated flows showed significant effects on the six behaviors studied; bentazone and nico sulfuron affected three and five, respectively. At the lowest concentration , prochloraz also showed more effects than the two other pesticides. Some o f the behavioral endpoints. were found particularly sensitive to a given ch emical. Pesticide-contaminated flows also induced significant changes in sw imming orientation of the fish. Attraction was observed in response to flow ing solutions of prochloraz (1 mg/L,10 mg/L), bentazone (10 mug/L, 10 mg/L) , and nicosulfuron (I mg/L, 10 mg/L). At a concentration of 1 mg/L, none of the pesticides induced a noticeable depolarization of the olfactory epithe lium, suggesting that these chemicals are not detected by the olfactory sen se of the fish. These results are discussed in the light of the data concer ning effects of pesticides on behavior and chemical communication in fish.