This is why Nico and I make a good fishing team - he is never afraid to call me a dumbass :)

Here is the study he is referencing:

http://edis.ifas.ufl.edu/fe693

It's a bit confusing to read but if you look at the table at the bottom, a more accurate comparison of the alternatives according to the writers is to say that doing nothing about mussels will cost Florida will cost $244 million while inspecting and educating will cost $55 million.

Included in that $244 million loss value is $219 million for "Lost Wetland Function". I have no idea what the means because the article does not define it. Intentional vagueness is a common tactic of people who are trying to convince you of things that are unfounded. I suspect that it is not an economic impact, but more of an intangible impact to society of damage caused to wetlands.

This is why we have to read this kind of "evidence" carefully and use a critical eye when evaluating it.

I consider myself an environmentalist and do not like the idea of unnecessarily spreading species around the globe. At the same time I am a realist who believes that successful species should not be vilified when it is the humans who stupidly drug them around to new places.

We're all big fans of survival of the fittest until our own stupidity causes weaker species to get quashed by species that we introduce.