Five different species of lamprey live in the Great Lakes region

Many people believe the invasive sea lamprey is the only one that exists.

Northern brook lamprey are found in brooks, streams, and small rivers. Photo: Minnesota Department of Natural Resources

Northern brook lamprey are found in brooks, streams, and small rivers. Photo: Minnesota Department of Natural Resources

Many people who fish in the Great Lakes region are aware of the sea lamprey that invaded the Great Lakes from the Atlantic Ocean in the 1930s and 1940s. It had a devastating effect on the Great Lakes fishery nearly bringing lake trout to extinction. Besides the non-native sea lamprey there are four native lamprey living in the Michigan Great Lakes region.

Lamprey, at times, are incorrectly referred to as eels. Eels are a more modern fish that has a developed jaw, is covered with scales, and has a bony vertebra. In contrast lamprey are primitive fish that have a funnel-like mouth, lack scales, and have cartilage instead of bone.

The native lamprey that exist in the Great Lakes region include the chestnut, silver, American brook, and northern brook lamprey. The chestnut and silver lamprey are parasitic in their adult stage and feed on body fluids and blood of fish. They can leave a deep wound in the fish that they feed on but rarely kill the host fish as the sea lamprey does. The American brook and the northern brook lamprey are not parasitic on fish and do not feed in their adult life stage.

The invasive sea lamprey is the largest of the lamprey in the Great Lakes and can attain a size of two feet. The two native parasitic chestnut and silver lamprey can reach a size of one foot. The two native non-parasitic American brook and northern brook lamprey reach a maximum size of about six inches.

People rarely see lamprey because of its secretive habits. Lamprey spawn in streams and after the eggs hatch the larvae burrow into tunnels in the stream bottom. The larvae, with their heads near the surface of the bottom of the stream, feed on organic particles, algae, and microscopic organisms. This larval stage can last for three to seven years.

The adult stage is relatively short for all lamprey and ranges from eight to twenty months. The beginning of the summer is when the parasitic lampreys emerge as adults and begin to parasitize fish. For native non-parasitic lamprey transformation into adults begins in the fall of the year and their digestive tract becomes non-functional and they stop feeding. After transformation into adults, lamprey swim freely in the water.

All lampreys achieve sexual maturity in the spring and are usually more active at night. In preparation for spawning, lamprey build nests in rivers and streams. After spawning both the male and female adult lamprey die. The chestnut and silver lamprey both live in rivers. The American brook and northern brook lamprey are found in brooks, streams, and small rivers with the American brook lamprey preferring to live in colder water.

Michigan Sea Grant helps to foster economic growth and protect Michigan’s coastal, Great Lakes resources through education, research and outreach. A collaborative effort of the University of Michigan and Michigan State University and its MSU Extension, Michigan Sea Grant is part of the NOAA-National Sea Grant network of 33 university-based programs.

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