Sorry, but I cannot even contemplate your reasoning! If a tiger escapes from a zoo, should we just allow it to roam free and eat people? It is only doing what an animal does! Here are just a few of my list to get rid of in North America.
Feral Cats (never happen but keep trying)
Nutria (possible)
Brown trout (never happen but keep trying)
Common Carp (never happen but keep trying)
Kudzu (never happen but keep trying)
These are just a few that are non-native to North America.
Ah, now see who needs to do some more reading. For your information Nutria makes some damn fine eating. I suggest you check out a Louisiana cookbook from your local library.