Asian carp have been a menace to American waterways since they were first introduced as farm fish in the 1970s. Asian carp species (silver, bighead and black carp) are highly invasive and detrimental to native animals. Reports show that they are expanding out of the Mississippi River and are threatening the Great Lakes, which provide a multi-billion dollar sport and commercial fishing industry for nearby states.
Asian carp are notable for competing with other fish species for food, often leading to a die-out of native fish. According to the National Wildlife Federation, Asian carp amount to as much as 97% of fish mass in portions of the Illinois and Mississippi rivers. For the last several years carp have been moving upriver to the boundaries of Lake Michigan.
Current points of entry to the great lakes include the Chicago Waterways sewage system, flooding from the Wabash and Maumee rivers, and ship canals. The U.S Army Corps of Engineers have set up three electric barriers to ward off carp from getting into Lake Michigan, as well as implementing fish kill methods. The Illinois Department of Natural Resources conducted a large-scale fish kill in 2009 when one of the electric barriers was shut down for maintenance. One Asian carp was found.
The National Park Service reports that continued spread of the carp could result in populations reaching across 40% of the continental United States, causing massive damage to local ecosystems. See the animation detailing the spread of Asian carp since 1975 below.
Animated Image from United States Geological Survey, National Wildlife Federation. featured image from the National Park Service