Agencies, universities, private industry and others are developing and implementing control efforts for established AIS to reduce their negative impacts.

The Great Lakes are already heavily invaded and ongoing economic and ecological impacts of a variety of established species continue to impede recovery of valued species and fisheries. Thus restoration of the Great Lakes fisheries and ecosystem will require that the impacts of a number of established AIS are controlled at either regional or local scales. Furthermore, when prevention and response programs are unsuccessful, containment and control strategies can be used to prevent further spread buy time to develop new methods to eradicate or more cost-effectively control these new invaders.

One example of this is with Hydrilla (Hydrilla verticillata). This highly invasive plant forms dense mats, crowding out native plant species that are important for fish and wildlife and impeding navigation and recreation. Hydrilla is infesting waterbodies in western New York and the U.S. Army Corps of Engineers, working with local partners and the New York State Department of Environmental Conservation, is implementing a multi-million-dollar research and control program that includes application of herbicides and physical removal to prevent further spread and avoid the environmental and economic consequences of a widespread invasion.

© Eric Blackmore/The Nature Conservancy

Widespread harmful species such as the sea lamprey, can sometimes be managed with environmentally-acceptable chemical, physical, and biological control methods including attractants and repellents. Sea lamprey control in the Great Lakes basin costs $20 million a year, and is managed by the Great Lakes Fishery Commission, incorporating all the aforementioned tools. Integrated management programs also exist for established plant species such as Eurasian watermilfoil and Phragmites. As with all AIS management strategies, these efforts require regional cooperation and coordination to be successful. Successful management also arises from long-term investment and commitment to research and adaptive management.