Today we begin an extensive series called "Ten Threats to the Great Lakes." The Great Lakes Radio Consortium's Lester Graham reports on how the shipping industry helped move goods into the major cities on the Lakes, but they also brought invasive species. He looks at the money Americans spend to deal with invasive species like zebra mussels.

Invasive species have been a real problem for native species in the Great Lakes, but some native species are turning tails on the invaders. The Great Lakes Radio Consortium's Rebecca Williams reports on the evolving relationship between a rare water snake and an invasive fish.

There are new problems for the Great Lakes on the horizon. The Great Lakes Radio Consortium's Zach Peterson reports that invasive species are crowding out the native species in the Lakes, and disrupting the natural food chain; Peterson says there will likely be more coming.

The Great Lakes Radio Consortium's David Sommerstein reports on how the invasive sea lamprey got into the Great Lakes. In this story he guides us through the history of one of the earliest invaders.

One of the first invasive species to arrive in the Great Lakes was the alewife. The Great Lakes Radio Consortium's Peter Payette reports on how the alewife has become the most loved invader because it provides food for popular sport fish.

Experts across the country agree that invasive species pose the greatest threat to the Great Lakes. The Great Lakes Radio Consortium's Lester Graham reports on one major route for invasive species… the ballast tanks of ocean-going ships.