DELAYED EFFECTS OF SUB-LETHAL LAMPRICIDE, 3-TRIFLUOROMETHYL-4-NITROPHENOL (TFM), EXPOSURE ON THE METABOLIC PHYSIOLOGY OF JUVENILE LAKE STURGEON (\u3cem\u3eACIPENSER FULVESCENS\u3c/em\u3e)

The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) can be lethal to juvenile lake sturgeon (Acipenser fulvescens) at high concentrations used to control invasive sea lamprey (Petromyzon marinus). Little is known about how TFM would affect juvenile lake sturgeon (age-0) at the sub-lethal concentrations encountered during routine lampricide treatments; specifically, its effects on growth, stress response, and metabolism. Age-0 lake sturgeon were exposed to TFM concentrations at levels 0.0x, 0.5x, and 1.0x the minimum lethal concentration (mlc) of TFM required to kill 99.9% of sea lamprey larvae during a routine stream treatment. The mlc was estimated based on pH and alkalinity of water in the lab and U.S. Fish and Wildlife Service TFM prediction charts. Sub-lethal exposure to TFM did not affect growth or stress response; however, metabolism was significantly reduced (p=0.048) for sturgeon exposed to the 1.0xmlc compared to controls fourteen days after exposure. Additionally, metabolism varied over time due to TFM exposure and was significantly higher (p=0.037) for fish exposed to the 1.0xmlc than controls for up to seven days after exposure. The results of this study suggest that sub-lethal TFM exposure causes prolonged variation in metabolism of juvenile lake sturgeon, which could negatively affect fitness and survival as they age. Future studies should focus on changes in mitochondrial dynamics and densities as a result of exposure to TFM in order to clarify the mechanism of effect