The correct answer to this open question is the following.
The Asian carp got to America because people brought them from Asia for consumption purposes. However, Asian carp is a problem because they do harm the aquatic environment, as happened in the Great Lakes
The Chicago Sanitary and Ship Canal finds it difficult to permanently close to keep the Asian carp out of the Great Lakes. However, it has established programs aimed to control and limit the access of the Asian carp into the Great Lakes to reduce the damage it provokes.
The Asian Carp feed on the bottom of the food chain, eating plankton of the lakes. But this plankton is necessary to keep the "health conditions" of the water of the lakes.
The U.S. Department of the Interior has declared all silver carp to be a dangerous species and legislation was written to protect the Great Lakes.
