AP reports on a new study by a federal environmental agency that indicates that there is a high risk of even more invasive species being transported to the Great Lakes in the near future:
 

Dozens of foreign species could spread across the Great Lakes in coming years despite policies designed to keep them out, causing significant environmental and economic damage, a federal report says.

The National Center for Environmental Assessment issued the warning in a study released this week. It identified 30 nonnative species that pose a medium or high risk of reaching the lakes and 28 others that already have a foothold and could disperse widely.

The report focused particularly on several key ports in the region through which many ships pass. Invasive species typically are transported into the Great Lakes in the ballast tanks of ships and the report indicates that some species may be able to get in even if those ships follow the law and flush their ballast tanks before entering the lakes.