Aquatic invasive species have irreversibly altered the Great Lakes ecosystem. Since 1959, the international vessels that ply the St. Lawrence Seaway have brought with them 57 of these unwelcome creatures.¹ Once here, both international and domestic vessels can spread species from lake to lake. The most visible symptoms of this crisis have been scattered across our shores in the form of tens of thousands of dead waterfowl and fish, decomposing algae, and a sea of tiny, sharp, mussel shells.

The true damage caused by these plants and animals goes much deeper. Ecologically, zebra and quagga mussels have upended energy flow in the lakes, smothered native clam populations, and are suspect in the precipitous decline of Diporeia, a freshwater shrimp-like invertebrate that is the foundation of the food chain but has now disappeared from many parts of the lakes. Economically, new research estimates that in the eight Great Lakes states alone, ballast-mediated invasive species are costing the Great Lakes fishing industry, wildlife watching industry, and water users at least $200 million dollars annually in damages and increased operating costs, with similar damage anticipated in Canada.²

The Great Lakes are the front door to the heart of North America’s freshwaters. In the two decades since their arrival, zebra and quagga mussels have spread as far west as Nevada and California and are moving inland throughout Ontario and Quebec, damaging waterways along the way. The U.S. and Canadian governments must commit to ending this threat once and for all.

Notes:

¹     USGS. 2009. Nonindigenous Aquatic Species Database, Gainesville, FL. http://nas.er.usgs.gov

²     Annual Losses to Great Lakes Region by Ship-borne Invasive Species at least $200 Million. David Lodge and David Finnoff. July 2008. http://www.glu.org/sites/default/files/lodge_factsheet.pdf