Rapid Detection of Sublethal Toxicity Using Locomotor Activity of Rainbow Trout Juveniles

This study examined changes in locomotor activity of the rainbow trout (Oncorhynchus mykiss) juveniles exposed to sublethal concentrations of hexavalent chromium (Cr⁶⁺) (as a single pollutant) and landfill leachate (as an complex mixture of mainly organic compounds, including trace amounts of metals). Fish were first examined for baseline behavior patterns for 3 h to determine the appropriate duration of acclimation and the control level. The average velocity of fish was found to be the most informative among other endpoints throughout the 3 h long acclimation. Under the effect of both test substances, fish locomotor activity significantly increased after 5 min reaching maximum values after 10 min of exposure. The juveniles exposed to leachate were more responsive than those exposed to Cr⁶⁺. However, in this study we did not succeed in identifying pollutants from the elicited fish behavioral response patterns.