Study offers groundbreaking insights for invasive species control and fish conservation in the Great Lakes
A new study published in the Journal of Experimental Biology has uncovered fascinating insights into the movement patterns of sea lampreys—a parasitic and invasive species threatening native fish in the Great Lakes ecosystem. Researchers from Michigan State University (MSU) have found that sea lampreys migrate by following the deepest sections of river channels, also known as thalwegs.
This discovery could revolutionize how scientists and conservationists manage sea lamprey populations, protect native fish species, and preserve the $7 billion Great Lakes fishing industry, which supports more than 75,000 jobs across the U.S. and Canada.
Tracking Invasive Sea Lamprey in the Great Lakes
Lead researcher Kandace Griffin, a doctoral student in fisheries and wildlife, along with Professor Michael Wagner from MSU’s Department of Fisheries and Wildlife, used acoustic telemetry—a fish-tracking method similar to GPS—to monitor 56 sea lampreys in the White River near Whitehall, Michigan.
Each fish was implanted with a sound-emitting tag carrying a unique identification code. This allowed researchers to triangulate their positions and study how the lampreys responded to environmental cues within the river.
“We discovered that nearly half of the sea lampreys—about 46%—consistently chose the deepest parts of the river during migration,” said Griffin.
A New Direction in Sea Lamprey Management
Historically, lamprey control methods have relied heavily on physical barriers like dams and the use of lampricide—a targeted pesticide effective at eliminating lamprey larvae. However, these methods have limitations:
- Dams obstruct the movement of other migratory and native fish species.
- Lampricide, while effective, has raised environmental concerns among some communities.
“We’re facing growing societal pressure to remove dams for better river connectivity,” said Wagner. “We need alternative solutions that are both effective and environmentally conscious.”
The new findings present a potential third option: developing trapping systems designed specifically for sea lampreys in deep river zones. Such systems could complement existing methods while promoting biodiversity and free-flowing rivers.
Learning from Indigenous and Traditional Knowledge
While modern fishing devices for bottom-swimming, nocturnal sea lampreys don’t currently exist, Wagner believes valuable insights could come from Indigenous and traditional fishing communities.
“People have been fishing migratory lampreys for centuries,” he said. “We want to collaborate with these communities to co-develop new fishing devices tailored to lamprey behavior.”
The research team has proposed a global effort to combine traditional ecological knowledge with scientific data to build effective, eco-friendly sea lamprey traps.
A Vision for Sustainable Fishery Management
The long-term goal is to offer science-driven, practical tools to fishery managers and communities seeking safer alternatives to chemical and physical barriers.
“We want to provide 360-degree solutions—knowing where, when, and how to fish lampreys with fully tested equipment,” Wagner emphasized.
Griffin adds that this approach could become a sustainable supplement to current lamprey control strategies, ensuring river ecosystem health and species conservation.
🔍 Key Takeaways:
- Sea lampreys prefer migrating through the deepest parts of rivers.
- Acoustic telemetry helped track these patterns with high precision.
- New strategies could reduce reliance on lampricide and dams.
- Collaborating with traditional fishing communities may lead to innovative solutions.
- This research supports fish conservation, ecosystem connectivity, and a thriving Great Lakes fishery economy.
📚 Reference:
Griffin, K. R., & Wagner, M. (2025). Not all who meander are lost: migrating sea lamprey follow river thalwegs to facilitate safe and efficient passage upstream. Journal of Experimental Biology. DOI: 10.1242/jeb.249539
📝 Source: Michigan State University