Lake Sturgeon (Acipenser fulvescens, LST) is a state and tribal species of special concern and a nontarget species sensitive to lampricides in certain stream water chemistries. As such, there is significant interest in the Great Lakes fisheries community to develop alternative sea lamprey (Petromyzon marinus, SL) control approaches for applicable LST producing streams that would reduce the impact on LST. Currently, streams are treated with a single 10-14 hour continuous lampricide block wherein the lampricide concentration is above the SL nine hour minimum lethal concentration (MLC) for at least nine hours. An interrupted lampricide block, wherein the treatment consists of two lampricide blocks (cumulative MLC of at least nine hours) with a break in the middle, decreases burrowing mayfly (Hexagenia limbata) mortality and results in no change to MLC for breaks up to twelve hours. Toxicokinetic and toxicodynamic studies of TFM in LST and SL indicate that differences in physiology, metabolism and clearance could allow LST (but not SL) to recover in part or in full during a lampricide block interruption. This indicates a mechanistic basis for decreased LST (but not SL) mortality during an interrupted lampricide block relative to a continuous lampricide block. This study compares mortality of LST and SL during continuous and interrupted lampricide blocks with the goal of establishing whether an interrupted lampricide block can be used to protect LST while maintaining treatment effectiveness.
Comparison of Continuous and Interrupted Lampricide Block Toxicity to Sea lamprey and Lake Sturgeon