Jennifer Orth over at the Invasive Species Weblog has in interesting post on the Zebra Mussel's recent "invasion" into the San Justo Reservoir in San Benito County here in California. The county is in the San Jose-Sunnyvale metro area (Northern Cal.) but it is a cause for concern in that it serves as an indicator of the mussel's effective western "movement". Take a look: http://invasivespecies.blogspot.com/
Jennifer's blog is a great source of information. I started monitoring her posts because of my concerns over Zebra and Quagga Mussels. I've since learned a lot about the many different animals and plants who are living and thriving in "places they shouldn't be".
If invasive mussels interest you, check out the Gondola Blog posts from November 16th and 19th of this year.