Why It Matters
Sea lampreys attach to and kill native fish, making their decline significant for Great Lakes fisheries and ecosystems. The Great Lakes Fishery Commission said regional control efforts are working across nearly all of the lakes.
What Happened
Sea lamprey populations fell this year in Lake Michigan, Lake Huron and Lake Superior, while Lake Erie recorded a small increase that remained within its target range.
The commission has coordinated lamprey control with regional partners for more than 70 years. The work generally combines barriers and lampricides in rivers where lampreys spawn.
Greg McClinchey, the commission’s director of policy and legislative affairs, called the decline good news for fishing and Great Lakes ecosystems. Michael Wagner, a Michigan State University professor of fisheries and wildlife, said lamprey numbers rose after field work was restricted during the COVID-19 pandemic and have since returned to earlier levels.
By the Numbers
More than 70 years — duration of commission control efforts with regional partners
20,211 — estimated adult sea lampreys in Lake Michigan
About 1,000 — Lake Michigan’s decline from last year
29,602 — sea lampreys in Lake Huron
Nearly 15,000 — Lake Huron’s decline
29,767 — sea lampreys in Lake Superior
More than 10,000 — Lake Superior’s decline from the year before
120 — Lake Erie’s lamprey increase
Zoom Out
Researchers are studying ways to capture lampreys in open rivers, improve lampricides and develop nonchemical controls. The management work could support native fish restoration and the reconnection of rivers.
Climate change is contributing to more extreme floods and changing fish migration patterns, adding conditions that researchers are examining as lamprey control continues.
What’s Next
Construction of FishPass on the Boardman-Ottaway River in northern Michigan will finish next year. The project is designed to pass certain fish while excluding invasive species such as sea lamprey.