As aquarist we have done our part to introduce animals/fish/plants to our natural system that should not be here. But we are not the soul source of getting undesirable things in our hemisphere. Some examples: Fire Ants, Killer Bees, Euroasian Doves and so on. How many things have come hitch hiked to the bottom of a ship or stuck inside of a box? I remember once in 1992 fishing in the Port Isabel ship channel when a friend hooked a Porcupine Puffer, wonder where that came from or snorkeling in Mexico last year when my wife saw a Clown Trigger? What about how the Axis deer is taking over Whitetail habitat? The Red Deer intermixing with our American Elk? The list continues.