If the fish were to reach the Great Lakes, it would be an ecological disaster.
The Great Lakes have struggled for decades from more than 150 invasive species brought in by ocean-going vessels dumping water from around the world. The Asian carp is the first major threat to come from the other direction, upstream from the Mississippi River.
They can be found about 45 miles downstream from Lake Michigan, squeezing aside native fish populations and ruining rivers for recreation because of their penchant for porpoising out of the water and battering boaters.