BEHAVIORAL-RESPONSES TO ATRAZINE AND DIURON IN GOLDFISH

Experiments were performed in goldfish to determine the effects of a s hort-term exposure (24 h) to atrazine or diuron (0.5, 5, 50 mu g/L) on some behavior endpoints related to swimming and social activities. Ob servations were also made to assess the influence of such exposure on the behavioral responses of fish to the flow of a crude skin extract s olution from conspecifics, active in social chemocommunication and pro ducing alarm behaviors. Additive tests were run to check the behaviora l responses of previously unexposed goldfish to the flow of a solution of atrazine- or diuron-contaminated water, at three concentrations (0 .1, 1, 10 mg/L). Significant burst swimming reactions appeared in resp onse to a 24-h exposure to atrazine, at the lowest concentration teste d (0.5 mu g/L). A 24-h exposure to 5 mu g/L atrazine or diuron was fou nd to induce various significant behavioral alterations in fish. At th is concentration, both herbicides decreased grouping behavior and atra zine also increased surfacing activity. Herbicide-exposed fish showed a decreased grouping behavior during the flow of the skin extract solu tion. Sheltering was also decreased during the Row of the biological s olution in fish exposed to atrazine. Moreover, fish exposed to diuron clearly displayed attraction responses to the how of the skin solution . Previously unexposed fish showed a significant increase in burst swi mming reactions in response to the flow of a solution of atrazine- or diuron-contaminated water, at all concentrations tested (0.1, 1, 10 mg /L). Furthermore, the diuron-contaminated flow was found to be signifi cantly attractive at the highest concentration. These results indicate that a short-term exposure to a relatively low concentration (5 mu g/ L) of atrazine or diuron can affect various behaviors of fish not only directly but also indirectly by altering the chemical perception of n atural substances of eco-ethological importance. In consideration of t he basic role of olfaction in fish behavior, these results also emphas ize the need for further developments on the possible effects of aquat ic toxicants on olfactory-mediated behaviors.