"Four species of non-indigenous Asian carp are expanding their range in U.S. waterways, resulting in a variety of concerns and problems. Three species--bighead, silver, and black carp--are of particular note, based on the perceived degree of environmental concern. Current controversy relates to what measures might be necessary and sufficient to prevent movement of Asian carp from the Mississippi River drainage into the Great Lakes through the Chicago Area Waterway System. Several bills have been introduced in the 112th Congress to direct actions to avoid the possibility of carp becoming established in the Great Lakes. According to the Great Lakes Fishery Commission, Asian carp pose a significant threat to commercial and recreational fisheries of the Great Lakes. Asian carp populations could expand rapidly and change the composition of Great Lakes ecosystems. Native species could be harmed because Asian carp are likely to compete with them for food and modify their habitat. It has been widely reported that Great Lakes fisheries generate economic activity of approximately $7 billion annually. […] Notably, each of these bills, as well as H.R. 4406 and S. 2317, would require the Corps of Engineers to complete the Chicago portion of a study on hydrologic separation of the Great Lakes and Mississippi River Basin within 18 months of enactment. H.R. 2432 would require the Corps of Engineers to prepare an economic impact statement before carrying out any federal action relating to the Chicago Area Water System. H.R. 4146 and S. 2164 would authorize the Corps of Engineers to take actions to manage Asian carp traveling up the Mississippi River in Minnesota."
CRS Report for Congress, R41082