Clayton, NY, Feb 02, 2010 — Invasive species - from zebra mussels and round gobies to the bloody red shrimp discovered three years ago - are one of the top threats to the Great Lakes and St. Lawrence River. They've done billions of dollars in damage to the region's economy and environment. Most entered the Great Lakes through the ballast water of foreign ships on the St. Lawrence Seaway. Jeff Alexander has reported on invasive species for 25 years. He's also written a book about how most of those critters got here - hidden in the ballast of foreign ships on the St. Lawrence Seaway. The book is called Pandora's Locks: The Opening of the Great Lakes-St. Lawrence Seaway. Alexander is the keynote speaker at the Save the River Winter Weekend, Saturday, February 6 at the Clayton Opera House. Alexander told David Sommerstein he first training his reporting in invasive species in 1989, when zebra mussels shut down the municipal water system in Munroe, Michigan.