One of the things we've learned about successful eradication of invasive species in general, not just aquatic ones, is that there are some patterns that differentiate successful eradication from the more dominant, more common, unsuccessful ones.
One of the things we've learned is that it depends greatly on early detection. The more area a species occupies before you start trying to attack it, the more man-hours and money you will have to put forward to attempt to control it, and you may not be successful. That is all dependent on time. When a species comes in, if it is successful, it will start building a population that's self-sustaining. As it builds, it will grow faster and faster through what Dr. Johnson called an Allee effect. That's just a technical term meaning there's density-dependent growth. It will also start to spread, and its rate of spread is dependent on how many there are. So the rate of spread increases with population growth.
So two things happen. There will be more of them, and they'll start to move. And as they move, they'll interface with other human vectors, all kinds of crazy ones that we may not anticipate, and they'll get spread even further in some cases. So that means that time is critical. You have to recognize the species, identify it, prioritize it—which requires careful risk assessment that has to be done rapidly and effectively—and then you can decide whether you can eradicate or contain it. If you can't, then you're going to be paying the chronic cost, because it won't go away.