Michigan Sea Grant > Aquatic Invasive Species

Mollusks

Zebra mussels
Dreissena polymorpha

Zebra mussels are a barnacle-like mollusk (mussel) native to the Caspian Sea region of Asia
They were discovered in Lake St. Clair in 1988 and have spread to all five Great Lakes.
Zebra mussels attach themselves to hard objects such as submerged rocks, dock pilings, boat hulls, and native clams and mussels (killing them).
They clog water intake pipes at power plants and water treatment facilities and cost millions to control each year.
Zebra mussels multiply rapidly and filter large quantities of plankton from the water and contribute to toxic algal blooms (microcystis), aquatic plant growth and food web disruptions.
Zebra mussels have contributed to declines in Great Lakes fish, such as yellow perch.
Fact sheet (PDF)
Help monitor zebra mussels

Quagga mussels

Quagga mussels are close cousins of zebra mussels and have outnumbered zebra mussels in several areas of the Great Lakes.
They are slightly smaller than zebra mussels and have rounder shells with dark concentric rings.
Quagga mussels have been found in lakes Ontario, Erie and Huron, as well as the St. Lawrence Seaway and the Saginaw Bay.
Fact sheet (PDF)

Aquatic Invasive Species Poster Series

Colorful illustrations, photos and graphics help 4th – 8th grade students understand why invasive species are a problem and what can be done.
See: Details

Updated: 09/04/2007

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