Data and Code Release: Determination of Larval Sea Lamprey (Petromyzon marinus) Seasonal Sensitivity Differences to Lampricide Treatment

Controlling larval sea lamprey (Petromyzon marinus) in Great Lakes tributaries with 4-nitro-3-(trifluoromethyl)phenol (TFM, a pesticide) stream treatments reduces the number of spawning-phase sea lamprey, an invasive species capable of collapsing Great Lakes fisheries. An important component of stream treatments is ensuring that the proper amount of TFM is applied that will effectively control sea lamprey populations and minimize the effects on non-target species. In this study, replicated streamside bioassays were conducted in May, July, and September at six sea lamprey infested rivers in Michigan to determine potential seasonal changes in sensitivity of lamprey to TFM. Larvae (≥ 60 mm) were collected with backpack electrofishing units and exposed to TFM streamside in continuous flow parallel diluters systems for 12 hours. Water chemistry and larval condition data were collected during the tests used in models to predict seasonal changes in the sensitivity of larval sea lamprey to TFM. The calculated minimum lethal concentrations to larval sea lamprey were 0–40% lower (May), 8% Lower–59% higher (July), and 49–117% higher (September) than predicted concentrations listed on the treatment charts utilized by sea lamprey control personnel. Water temperature and larval liver glycogen concentrations appear strongly associated with seasonal sensitivity differences.