Reuters: Invasive species that have hitched rides into the Great Lakes since they were connected to the sea nearly 50 years ago are causing $200 million a year in damages, according to a study published on Wednesday. The figure is conservative and does not include damage done to the Canadian economy or other parts of the United States where some of the invaders have travelled by water, said the report from the Center for Aquatic Conservation at the University of Notre Dame in ...Link