The Great Lakes Basin is among the most heavily invaded freshwater systems in the world. Its food webs are dominated by invasive species that change how the ecosystem functions and result in substantial economic costs to the region by limiting access to clean water, interfering with recreation, disrupting fisheries and hurting tourism.

Why Aquatic Invasive Species Matter

Why It Matters

Zebra Mussels

cleaning zebra mussels at treatment plant

Zebra mussels and other AIS can have big economic impacts. In Monroe, Michigan, the water supply was shut down by zebra mussels clogging the intake pipes (pump room clean out pictured above). Removing invasive mussels from a single water treatment plant can carry substantial cost. The economic impact of AIS on Great Lakes businesses and households is conservatively estimated to cost millions of dollars annually.

© Peter Yates/Getty Images


Alewife contribute to loss of native species

AIS such as sea lamprey and alewife (seen above dying in large numbers due to overpopulation) have contributed to reduced lake trout, whitefish, herring and prey species populations. During the mid-20th century, the impact was so great that some native fish populations collapsed. In combination with other invaders like zebra mussels, quagga mussels, and the round goby, these AIS make food sources unpredictable for native species, which brings instability to commercial and sport fishing economies in the Great Lakes.

©Bettmann/Getty Images

Sea lamprey feeding on salmonid fish

starry stonewort blocking diver's path in lake

AIS can interfere with our ability to enjoy the Great Lakes. Starry Stonewort, for example, is an invasive plant that grows densely and prolifically. In addition to harming native organisms, it can grow so thick that boating, fishing, and swimming are nearly impossible.

© William "Lindsay" Chadderton/The Nature Conservancy

Who's Involved

The Great Lakes community is served by many forums working to advance AIS prevention and control including:

A collaborative Blue Accounting AIS work group comprised of regional experts who are members of these forums is providing input and expertise to develop the AIS issue for Blue Accounting. While the content on Blue Accounting does not necessarily reflect the views of any individual work group member or organization, this collaborative approach results in a comprehensive, regional picture of progress and is a product of their collective expertise.


How We Work

Blue Accounting is supporting efforts to advance effective and coordinated approaches to AIS management across the Great Lakes region. The Blue Accounting AIS work group is collaborating to identify and share information on strategies used to achieve regional AIS goals of prevention, detection and response, and control.  Blue Accounting is synthesizing existing data and information to:

Where We Work

Geographic Boundaries

Lakes and Streams

Great Lakes and streams to first barrier

The Great Lakes, connecting channels, and Great Lakes tributaries up to the first barrier form  one large interconnected water body with no barriers to prevent natural dispersal throughout the entire system. 


Great Lakes Basin

The Great Lakes and associated watersheds form one large catchment area. There are no natural barriers to prevent AIS introduced into the headwaters of any Great Lakes tributary catchment from spreading downstream into the Great Lakes.

GL States

Great Lakes States and provinces

Management of aquatic invasive species is driven primarily by state, provincial or federal management agencies, and regulations often apply to all waters within these jurisdictional boundaries.