With both Asian carp and zebra mussels, (and lionfish and starlings etc etc etc) we are essentially powerless to stop their advance. To extend your metaphor, we

With both Asian carp and zebra mussels, (and lionfish and starlings etc etc etc) we are essentially powerless to stop their advance. To extend your metaphor, we literally have nothing in the way of antibiotics and stitches to salve this wound. We need to be trying orders of magnitude more than we actually are to prevent such calamities from happening in the first place. People have this misplaced faith the we as a race can engineer our way of out any problem, and it's just not true. Ban the nail, I say.