Cooperative Fish and Wildlife Research Units Program: Montana Fishery
Education, Research and Technical Assistance for Managing Our Natural Resources

Brown, P. J., H. Johnson, and A. V. Zale. 2011. Effect of rainbow trout size on response to rotenone and antimycin. North American Journal of Fisheries Management 31:1146-1152.


The piscicides rotenone and antimycin are commonly used to eradicate unwanted fish populations. However, the relationships, if present, between their toxicities and fish sizes are unknown and could be especially important when bioassay fish are used to detect piscicide presence and effectiveness. Size-mediated toxicity could lead to either excessive or inadequate piscicide applications if bioassay fish are larger or smaller than the fish being eradicated. The relationships between time to death and rainbow trout Oncorhynchus mykiss weight (0.7 to 574.0 g) at 7.5 µg/L antimycin and 12.5 µg/L rotenone concentrations were determined. Significant positive relationships, probably caused by size-mediated differences in metabolic rates, existed between size and time to death in both rotenone and antimycin; however, these relationships accounted for less than 21% of the variation in time to death. The remainder of variation was probably caused by the phenotypic threshold effect rather than variation in uptake rate.