A fascinating post by longtime Adirondack writer and editor Mary Thill discusses new findings on yellow perch by a regional scientist. The scientist found the perch, long treated as an invasive species, may be native to the Adirondacks:
I think it's time we admit it doesn't matter whether a species is native. What matters is whether we like the species, based on things such as whether it inhibits recreation (Asian clams, Eurasian milfoil); outcompetes sport species (yellow perch, which drive out brook trout); or destroys other species we want to preserve (emerald ash borer, which kills ash trees; and Asian longhorned beetle, which kills sugar maples and other hardwoods).
Calling a species non-native is our excuse for trying to eliminate or at least prevent the spread of a species we consider destructive.
But moving around, whether it's done by swimming from one island to another, or by hitching a ride on a container ship, is a natural process. Species spread. Just look at humans (talk about invasive!).
We don't need an excuse beyond our own subjective determination of a species' destructiveness to decide to kill some and protect others.