In situ assessment of lampricide toxicity to age-0 lake sturgeon

Mitigation of lampricide toxicity to juvenile lake sturgeon: the importance of water alkalinity and life stage

“…One-year-plus (1+) old lake sturgeon ( N = 63; length = 138.8 ± 1.6 mm, mass = 7.8 ± 1.9 g) were acclimated to nominal water alkalinities of 50 mg L −1 as CaCO 3 (low alkalinity), 100 mg L −1 as CaCO 3 (moderate) or 250 mg L −1 as CaCO 3 (high) for 1 week and subjected to an acute survival test at a nominal TFM concentration of 3.5 mg L −1 . This value was within the range of concentrations likely to result in different survival rates and was within the range likely to be encountered by lake sturgeon during typical lampricide treatments (Bills et al , 2003; O’Connor et al , 2017). Water of the appropriate chemistry was prepared by mixing dechlorinated municipal tap water with reverse osmosis water at the Cold Regions and Water Science Centre at WLU followed by measurements of water pH, alkalinity, dissolved O 2 and temperature.…”

“…Lake sturgeon population recovery efforts could be complicated by sea lamprey ( Petromyzon marinus ) control efforts in the Great Lakes (O’Connor et al , 2017; Dobiesz et al , 2018). Sea lampreys are jawless fish that spend most of their life as relatively sedentary, filter-feeding larvae (ammocoetes) burrowed in the substrate of streams.…”

“…Lake sturgeon, however, are particularly vulnerable to TFM in their early life stages (Boogaard et al , 2003). They have been identified in 57 different rivers subjected to sea lamprey control operations, with historical evidence of lake sturgeon presence in 40 additional tributaries (O’Connor et al , 2017). Because they occupy the same reaches of streams as larval sea lamprey or ammocoetes, which live burrowed in the stream substrate as filter feeders, juvenile lake sturgeon can be exposed to potentially lethal amounts of TFM.…”

“…Another complication is that the tolerance of lake sturgeon to TFM appears to decrease relative to sea lamprey in waters of high alkalinity, in which much higher concentrations of TFM are needed to maximize sea lamprey eradication (Boogaard et al , 2003; O’Connor et al , 2017; Dobiesz et al , 2018). Alkalinity refers to the ability of water to buffer changes in pH due to the presence of HCO 3 − , CO 3 2− or other ions (Cole, 1988) and should not be confused with the term ‘alkaline’ which is used to describe solutions of basic pH (pH > 7.0).…”

Post-exposure effects of the piscicide 3-trifluoromethyl-4-nitrophenol (TFM) on the stress response and liver metabolic capacity in rainbow trout (Oncorhynchus mykiss)

“…Because TFM uncouples oxidative phosphorylation, exposure to high concentrations over several hours results in significantly reduced high energy phosphagens and glycogen reserves in rainbow trout ( Oncorhynchus mykiss ) muscle and brain [ 12 ]. However, few other studies have examined the sub-lethal physiological effects of TFM on non-target fishes [ 18 – 20 ], and we are unaware of any that have addressed how TFM affects the stress response of non-target fishes. The goal of the present study was to establish if exposure to sub-lethal, environmentally relevant, concentrations of TFM affect the physiology of the rainbow trout, with a specific focus on the hypothalamic-pituitary-interrenal (HPI) axis, which mediates the stress response of fishes, and on liver metabolic capacity, since the liver is involved in detoxification of pesticides.…”