When I was child, I was really enjoy crayfish fishing. The crayfish came from the US long time ago. Even when I was child, I could not see the original Japanese crayfish. Now the American crayfish is invading Africa. They are really changing the balance. Do you think this is USA responsibility? – No way! The “American” does not mean that it is developed by American people. They just come from American continental – so the naming is just really bad for the US people. So, is this responsibility of people? Yes and No. Yes, we bring them though the crayfish is just very strong as invader. This is human related though still natural.