The Effects of Triclosan On Reflex Responses and Anti-Predator Behaviors in An Estuarine Fish

Triclosan is an antibacterial compound found in many personal care products. Despite partial removal by wastewater treatment, an increasing amount enters watersheds where it significantly affects aquatic organisms. At low levels, triclosan negatively impacts thyroid homeostasis in anurans and fish and decreases startle responses and activity levels in anurans. Our objective was to investigate the effects of triclosan on reflex responses and anti-predator behavior in juvenile Atlantic croaker (Micropogonias undulatus), an estuarine fish. Sixty croaker were held individually and randomly assigned a diet of either untreated food pellets or pellets impregnated with 50 ppm triclosan for 14 days. Prior to and immediately following the exposure period, fish were tested for a suite of reflexes and were subjected to a video-recorded simulated predator attack. Videos were analyzed for the specific anti-predator strategies employed. We found that triclosan-exposed fish were significantly more likely than control fish to exhibit reflex impairment. Treated fish also displayed significant shifts in anti-predator strategies, spending significantly more time in their post-exposure test stationary than control fish. These behavioral effects may have important implications for croaker and similar fish species as well as for predators since contaminated fish may be easier prey, leading to increased predator body burdens.