Sea Lamprey Management and Welfare in the Great Lakes System

Sea lampreys are invasive parasites in the North American Great Lakes requiring active control programmes, raising welfare questions about the methods used and the impact on native lamprey species.

Key Facts

Sea lampreys invaded the Great Lakes via the Welland Canal in the 1920s
Each lamprey kills an estimated 18 kg of host fish during its parasitic phase
Control relies primarily on lampricide (TFM) application to streams where larvae develop
Native lamprey species share habitat with sea lampreys and may also be affected by control
Sea lampreys are capable of sensing their environment and responding to noxious stimuli

Welfare Considerations

Sea lamprey control programmes cause mass mortality of larvae through chemical lampricide application, raising questions about welfare for both target and non-target species. Chemical control with TFM causes death through respiratory failure over several hours. The scale of control is enormous, with millions of larvae killed annually. While control is justified by the ecological and economic damage caused by sea lampreys, ongoing research into species-selective control methods including pheromone-based trapping and barrier exclusion would reduce the welfare impact of control programmes on both sea lampreys and native species.

What You Can Do

Support research into species-selective and more humane sea lamprey control methods
Engage with the Great Lakes Fishery Commission on welfare considerations in control programme design
Advocate for investment in physical barriers and pheromone-based trapping as alternatives to lampricide
Monitor the impact of control programmes on native lamprey species through survey participation
Raise awareness of the complex ecological and welfare trade-offs in invasive species management