The Minneapolis Star Tribune just finished an excellent series on invasive species in the Great Lakes. Unfortunately, you will have to proceed through an annoying but free registration process to read all of the articles. Most interesting is this article from June 9th, which contains a list of 179 species in the Great Lakes marked as invasive (and describes the sources, bravo!). There's also this article about the lack of thorough ship-checks, a story about a woman's unpleasant encounter with a silver carp (Hypophthalmichthys molitrix), and an interesting piece about the attempt to prevent the spread of carp via an electric barrier. To see all related stories, you'll have to search the Star Tribune's archives.