Established and Emerging Control Measures for Sea Lamprey

The Great Lakes Fishery Commission uses lampricide formulations and physical barriers that deny access to spawning habitat to control the invasive, parasitic sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes. These control techniques can have unintended impacts on aquatic ecosystems.  While decades of use and research have demonstrated that pre-existing and purpose-built physical barriers successfully deny sea lamprey access to spawning habitat, these barriers can also reduce the passage of non-target fishes.  Newer combinations of barriers and fish passage facilities designed to selectively block sea lamprey while successful require manual sorting of fishes. Seasonally operating barriers to provide selective passage is ineffective because sea lamprey migrate at the same time as many native fishes.  Control tactics are needed for use in situations where negative impacts of a barrier outweigh sea lamprey control gains.  Trapping upstream-migrating adult sea lamprey has been explored, but current techniques rarely capture enough adults to effectively reduce reproduction.  Trapping downstream-migrating juveniles suffers from low trapping efficiency as well. Recent developments in understanding sea lamprey behavior show promise in enhancing trapping of both adults and juveniles through the use of pheromone attractants and repellents and may allow future replacement of barriers to increase aquatic habitat connectivity.