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Upper Midwest Environmental Sciences Center

Sea Lamprey

Sea Lamprey
Why are they a problem?

Sea Lamprey

Sea LampreySea lamprey prey on commercially important fish species, such as lake trout, living off of the blood and body fluids of adult fish. During its life as a parasite, each sea lamprey can kill 40 or more pounds of fish.
These organisms were a major cause of the collapse of lake trout, whitefish, and chub populations in the Great Lakes during the 1940's and 1950's.
Fast Facts
How far have they spread?
Native to Atlantic Ocean
Life span:
larvae — 3 to 17 years
adult — average 18 to 20 months
larvae — 6 inches
adults — 18 to 24 inches
Method of introduction: Through humanmade locks and shipping canals in the 1800's.
The sea lamprey was first discovered in Lake Ontario in 1835, Lake Erie in 1921, Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946. Reproducing populations were found in all of these upper lakes by 1947. The present "hot zone" is the St. Marys River. Sea lamprey produced in the St. Marys River migrate into Lake Huron and northern Lake Michigan. There, the adult sea lamprey population is nearly as large as it was 40 years ago–before sea lamprey control–when lake trout and whitefish stocks were decimated.

Sea Lamprey hot zone

What are UMESC scientists doing to help?

Helicopter applying granular Bayluscide

Helicopter applying granular Bayluscide to specific hot spots in the St. Marys River. This form of lampricide is intended to kill sea lamprey larvae on the bottom of the river.

The UMESC is providing technical assistance to the Sea Lamprey Control Agents in the United States and Canada. This assistance is in the form of data to support the re-registration of the lampricides with the Environmental Protection Agency, development of treatment models to reduce the amount of chemical needed, and development of improved formulations. The UMESC scientists developed a controlled-release formulation of Bayluscide that is designed to kill sea lamprey in the bottom sediments where they reside without impacting other nontarget organisms. This new formulation is expected to reduce the populations of sea lamprey in Lakes Huron and Michigan by about 85%.

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