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Michigan State University Extension
21885 Dunham Road, Suite 12, Clinton Township, MI 48036
(586) 469-6440

Aquatic Nuisance Species (ANS)


Aquatic nuisance species are non-native, or exotic, plants, animals and microscopic organisms that have caused problems in aquatic ecosystems outside of their native range.

Michigan Sea Grant supports research focusing on the impact of aquatic nuisance species in the Great Lakes and explores ways to control their spread and prevent future introductions. Current research topics include zebra mussel impacts and control, the effects of exotic fish such as ruffe and round goby and the economics of aquatic nuisance species prevention in the Great Lakes.  Michigan Sea Grant also holds workshops, distributes posters, fact sheets, identification cards and more.

Two of Michigan's biggest invaders are the Zebra Mussel and Purple Loosestrife.


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.
  • Zebra mussels have contributed to the decline of Diporeia, a shrimp-like organism and an important food source for whitefish. Diporeia, like other native species, has been in the Great Lakes since the Ice Age.


Purple Loosestrife
(Lythrum salicaria)

  • Purple loosestrife is a tall, flowering plant native to Europe that has invaded many North American wetlands and every watershed in Michigan.
  • Thick stands of purple loosestrife block access to water, overtake native wetland plants and reduce food and habitat for wildlife.
  • Management of purple loosestrife using biological control is beginning to reduce the invasive plant in some areas of Michigan.

For more information on Aquatic Nuisance Species,
visit the Sea Grant Web site at