In our next report from the series, Ten Threats to the Great Lakes, we look at the history of shipping on the lakes, and how some people think bigger ships could bring more trade to the region. The Great Lakes Radio Consortium's Lester Graham has this report.

We're continuing our Ten Threats series with a closer look at the idea of letting bigger ships into the lakes. The Great Lakes Radio Consortium's David Sommerstein looks into the shipping industry's desire to make the locks and channels of the St. Lawrence Seaway bigger so larger cargo ships can come in.

In this report from the Ten Threats series we hear about how a native fish has been hurt by an invasive species that swam into the lakes through a canal, and about new efforts to control this pervasive pest. The Great Lakes Radio Consortium's Stephanie Hemphill has that story.