Experts generally agree that aquatic invasive species (AIS) present

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3 Experts generally agree that aquatic invasive species (AIS) present one of if not the greatest threat to the Great Lakes ecosystem. These plants, animals and microscopic organisms originated elsewhere and have been introduced to the lakes, where they can harm natural resources, our ability to use those resources and even human health. More than 180 AIS have already been detected in the Great Lakes system, dozens more are considered immediate threats, and hundreds of others pose long-term challenges. A new species was discovered in the lakes every seven months on average until 2006 when new shipping regulations went into effect that may have slowed the invasion. Among the best-known AIS are the sea lamprey, zebra and quagga mussels, round goby, Eurasian ruffe, spiny waterflea, purple loosestrife and Eurasian watermilfoil. Scientists have documented many effects of AIS on ecosystems, but don t yet fully understand those effects due to the large number of invasives already in the basin, interactions among species and the complex food webs and ecology of the lakes. Among other impacts, AIS have altered or degraded habitat, stressing native species and putting some threatened and endangered species at even greater risk. They have also contributed to diminished water quality and harmful algal blooms. In addition to their ecological impacts, AIS deal a serious economic blow. According to an ongoing University of Notre Dame study, counting only those species that arrive in ballast tanks, AIS cost $200 million annually in the United States alone. Other research Student Overview Page 1 of 3

4 Introduction to Binational Aquatic Invasive Species Rapid-Response Policy Framework (cont d) indicates that the total cost may range from hundreds of millions to several billion dollars each year. The reasons for such a huge economic impact are numerous. Among other effects, AIS cost tourism dollars by degrading beaches, harming sport fish and diminishing the lakes aesthetic appeal, which also lowers property values. They hurt businesses and municipalities by impairing commercial fisheries and damaging boats and water infrastructure, leading to higher costs for water use. New species enter the lakes through numerous pathways, but the ballast tanks of transoceanic freighters are thought to have carried 55 to 70 percent of the AIS that have entered the lakes since the St. Lawrence Seaway opened in Others reached the lakes by hitching a ride on recreational boats, migrating from fish farms or swimming through canals, among many other routes. Once invasives have entered the Great Lakes St. Lawrence Basin, eradicating them is all but impossible, so the primary management focus has been on keeping them from ever entering the ecosystem. But given the immensity of the lakes, the numerous pathways by which AIS can reach them and the unique habits of each species, forming a first line of defense is a difficult task. Climate change is expected to make managing AIS even more difficult, and may already be doing so. For instance, increasing water temperatures in nearshore areas have made conditions favorable for the spiny water flea, zebra and quagga mussels, round goby and various carp species, and likely contribute to expansion of those species populations in the lakes. According to the U.S. Environmental Protection Agency, climate change may create new pathways for AIS to enter the lakes and make existing pathways more favorable to invasives. Furthermore, habitats in which AIS Student Overview Page 2 of 3

5 Introduction to Binational Aquatic Invasive Species Rapid-Response Policy Framework (cont d) are already established are thought to be especially welcoming to invasion by more non-native species. Experts say that when efforts fail to prevent AIS from entering the basin, an early detection and rapid-response program is needed as a second line of defense. This was made clear in the mid- 1990s when a small population of Eurasian ruffe were found in the Great Lakes. With a rapid response the ruffe could potentially have been eradicated. But faced with difficult decisions and without an established plan of action, managers were slow to take decisive action. As a result, the ruffe expanded its range and is now established in the lakes, serving as a constant reminder of the need for improved policies. If you re interested in learning more about AIS or other environmental issues in the region, please visit org/reports. There you can read reports from the work groups on invasive species and other issues, and find information about the Commission s biennial meeting in October, Student Overview Page 3 of 3