Effects of atrazine on swimming behavior of zebrafish, Brachydanio rerio

Effects of atrazine (5–3125 μg l−1) on the swimming behavior of zebrafish, Brachydanio rerio, were studied by recording and quantifying the spontaneous locomotor activity. Exposure to atrazine significantly (P < 0.0001) altered the behavior: the zebrafish preferred habitats with dark substratum of the aquaria. Since the different exposure concentrations did not reveal clearly different responses, we assume a threshold effect rather than a dose-effect relationship. Possible ecological consequences of these findings are outlined.