TEN THREATS: HIDDEN COSTS OF INVASIVES
In looking at these threats to the Great Lakes, almost everyone we surveyed agreed the worst threat was alien invasive species. Shipping goods in and out of the Great Lakes has helped build the major cities on the Lakes. But shipping from foreign ports has brought in unwanted pests. Zebra mussels are probably the most infamous, but there are more than 160 aquatic species that have invaded the Lakes and changed them, almost always for the worse. So why can't we keep them out?
Producer: Lester Graham
Release Date: October 10, 2005
Running Time: 4:27