I know some states, like Florida, have invasive species round-ups, where volunteers catch and remove non-indigenous species. As a kid, I used to visit my grandparents in St. Petersburg, Florida. Caught a bunch of African species like Tilapia and Nile Perch (Lates niloticus) and S.American fish like Oscars (Astronotus ocellaris). I know some hippies who'd be overjoyed if they found out that Grass Carp were dying off in large numbers, as both the Grass and Common Carp have been out-competing similar native species of fish (Buffalo Fish, ChubSuckers) for decades now.