The U.S. Army Corps of Engineers (USACE) Detroit District and Great Lakes Fishery Commission (GLFC) completed the installation of a $1.67 million permanent sea lamprey trap on the East Branch Au Gres River in Iosco County, Michigan. The completion of the project represents a long-standing partnership between USACE and GLFC to control invasive sea lampreys and protect the $7 billion Great Lakes fishery. Federal funding for this project was made possible by the GLRI.
Sea lampreys, parasitic fish that suck blood from other fish (e.g., lake trout and Pacific salmon), invaded the Great Lakes through shipping canals and devastated Great Lakes fisheries in the mid-1900s. Each sea lamprey can kill up to 40 pounds of fish per year, and an estimated 4,500 sea lampreys enter Lake Huron from the East Branch Au Gres River each year.
Since sea lampreys are most vulnerable to capture as they move from lakes into tributaries to spawn, the control program relies on physical barriers to block their upstream migration during the spring, thereby reducing the population. Specially designed traps are built into or placed immediately downstream of sea lamprey barriers to remove the spawning sea lampreys from the system and support assessment efforts of the control program.
The East Branch Au Gres River is one of nearly 60 Michigan tributaries trapped as part of the control program's network. The new East Branch Au Gres trap will likely be used as a model for similar trap construction projects in the future.