Invasives Eschew Great Lakes
Salt water ballast exchange reduces the chance that shipping causes AIS invasions. Image: News Tribune.
The Great Lakes have been the point of introduction for numerous aquatic invasive species over the years. Ocean-going cargo ships would exchange ballast water after arriving from Europe or Asia and accidentally dump the creatures that had survived the passage in a new home. That appears to be changing thanks to new regulations about ballast water discharge and treatment and no new invasives have been confirmed in the Great Lakes since 2006.
A decade ago researchers were finding a new species in the Great Lakes on average every 28 weeks. Since 2006, the Coast Guard has enforced a ballast water exchange program. Ships now have to flush their ballast while still at sea. The salty water kills most organisms that thrive in freshwater.
The rate of introductions has slowed in Lake Champlain as well. Invasive introductions peaked in the 1990s when zebra mussels and 11 other exotic species found their way into the lake. Since 2010, there has been only one known introduction, spiny waterflea in 2014. In total, there are 50 invasive species in Lake Champlain, while the Great Lakes harbor at least 184 species. LCC actively promotes education programs, rapid response actions and closing the links through the Champlain Canal to keep new invasives out of the lake.
