I think probably the biggest lesson—and it gets to what Nick was saying—is that dealing with any invasive species is best done before it gets in and gets established. In Canada we're seeing that with how much it's costing us to address sea lamprey and the impact that it's had on commercial fisheries in the Great Lakes.
If we look into the United States and we see areas where Asian carp have become established, they have pretty much taken over the entire ecosystem. They make up about 90% of the biomass.
The traditional commercial fisheries would be gone and the impacts on the local economy would be devastating.