Meeting Abstract
Environmental contaminants such as agricultural runoff and pharmaceutical pollutants in freshwater systems have been shown to alter fish behavior. Such effects may be especially critical for prey fishes, as they could impact performance during behaviors necessary for survival, such as detection and escape from predators. We tested for effects of environmental contaminants on escape performance in juveniles of the Hawaiian freshwater goby Sicyopterus stimpsoni, a species that must migrate through predator-dense stream reaches on its way to predator-free adult habitats, but which is facing increasing risk of contaminant exposure in the downstream waters through which it migrates. We exposed juvenile S. stimpsoni to a combination of common pharmaceutical (sulfamethoxazole, methocarbamol, diclofenac, temazepam) and agricultural (alkylphenol mixture, estrone, triclosan) pollutants for five days at three concentrations representing a realistic environmental gradient of exposure. After exposure, the ability of surviving fish to produce an escape response was measured in an arena by applying a water-jet stimulus and filming with high-speed video. Trials were analyzed to determine how frequency of response, duration of response, and escape angle were affected by different concentrations of contaminants. Our analysis showed that while survivorship differed between treatments, with lower survival at higher concentrations, there was only a limited effect of contaminant exposure on escape performance. These results suggest that the impacts of contaminants on survivorship in this species are more likely to be direct than to be mediated through the ability to execute critical behaviors.
