Copper acute toxicity tests with Schizothorax o'connori Lloyd and Schizothorax waltoni Regan: a biomonitor of heavy metal pollution in a high altitude area?

Fingerlings of two different Schizothorax species, S. o'connori Lloyd and S. waltoni Regan, were exposed to copper for 264 h in a series of static toxicity tests. The mortality rates of these two species increased as the exposure concentrations increased and the exposure time was prolonged. Estimated 96 h median lethal concentration (LC50) values were 0.31 and 0.28 mg/L for the two species, respectively. These findings indicated that fingerlings of these species were sensitive to copper, and that both species may be suitable for use as local biomonitors of copper pollution in the high altitude environment. However, S. waltoni may be more useful in indicating the safe concentrations of copper used in aquaculture for therapeutic purposes. Further quantitative studies with measured concentrations of copper are required to verify the results observed in the present study.