Journal of Forensic Medicine

Managing Invasive Sea Lampreys with TFM and Niclosamide Piscicides: Toxicological Insights, Achievements and Future Directions

Abstract

Michael P. Madan

The incursion of sea lampreys (Petromyzon marinus) into the Laurentian Great Lakes of North America during the early 20th century led to the depletion of vital commercial, recreational, and culturally significant fish populations. This devastation severely impacted the economies of communities dependent on fisheries. In response, a robust integrated pest management strategy was employed to curb sea lamprey populations. This approach encompassed the installation of barriers and traps to impede their migration to spawning grounds, coupled with the utilization of piscicides (known as lampricides) including 3-Trifluoromethyl-4-nitrophenol (TFM) and niclosamide to eliminate larval sea lampreys from their nursery streams. Despite the Great Lakes still housing residual sea lamprey populations, their numbers have been curtailed to less than 10% of the peak levels observed in the mid-1900s, predominantly through the sustained application of lampricides. This initiative has heralded one of the most triumphant invasive species management programs globally. However, there exist significant knowledge gaps concerning the uptake, processing, and toxicological mechanisms of TFM and niclosamide in lampreys and non-target species. In the past decade, substantial progress has been made in elucidating these aspects.