Alteration of general behavior of male medaka, Oryzias latipes, exposed to tributyltin and/or polychlorinated biphenyls

We examined the general behavior of male Japanese medaka, Oryzias latipes, after exposed to tributyltin (TBT), polychlorinated biphenyls (PCBs), or a mixture of these chemicals at a concentration of 1 μg/g body weight daily for 3 weeks. We analyzed swimming velocity as an indicator of acute toxicity and counted the frequencies of straight swimming and swimming in circles. We also calculated the entropy of the positions of the fish within the experimental chamber. Neither TBT nor PCBs nor their mixture affected the swimming velocity, suggesting that there were no acute toxic effects. However, PCBs exposure increased the frequencies of both straight and circular swimming, suggesting hyperactivity. TBT increased the positional entropy value. Both TBT and PCBs affect the general behavior of mature male medaka, although exposure to the 2 chemicals together has no significant additive behavioral effect.