Asian Carp and the Great Lakes Region

Summary
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. Bills have been introduced in the 111th 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. Although Asian carp introduction is likely to modify Great Lakes ecosystems and cause
harm to fisheries, studies forecasting the extent of potential harm are not available. Therefore, it is
not possible to provide estimates of potential changes in the regional economy or economic value
(social welfare) by lake, species, or fishery.
The locks and waterways of the Chicago Area Waterway System (CAWS) have been a focal point
for those debating how to prevent Asian carp encroachment on the Great Lakes. The CAWS is the
only navigable link between the Great Lakes and the Mississippi River, and many note the
potential of these waterways to facilitate invasive species transfers from one basin to the other.
The U.S. Army Corps of Engineers has constructed and is currently operating electrical barriers to
prevent fish passage. However, in light of recent tests indicating the potential presence of Asian
carp in Lake Michigan, increased federal funding to prevent fish encroachment has been
announced by the Obama Administration, and calls to permanently separate the two basins have
grown. The potential closure of existing navigation structures in the CAWS and the permanent
separation of the basins are currently the most contentious issues related to Asian carp control in
the region, and a long-term solution has yet to be decided.
On January 19, 2010, the Supreme Court refused to order emergency measures sought by the
State of Michigan to stop the migration of invasive Asian carp toward Lake Michigan from rivers
and a sanitary canal in Illinois. Without comment, the Court refused to issue a preliminary
injunction that would have closed waterway locks and required other temporary measures in
reaction to the discovery of Asian carp upstream in Illinois rivers. On February 4, 2010,
Michigan's Attorney General Mike Cox filed a renewed motion, asking the Supreme Court to
reconsider issuing a preliminary injunction for the closure of Chicago-area locks based on new
evidence that Asian carp are present in Lake Michigan. Michigan's renewed motion for a
preliminary injunction was denied by the Supreme Court on March 22, 2010.
In the 111th Congress, Section 126 in Title I of P.L. 111-85 directed the U.S. Army Corps of
Engineers to implement additional measures to prevent invasive species from bypassing the
Chicago Sanitary and Ship Canal Dispersal Barrier Project and dispersing into the Great Lakes.
Other bills have been introduced to list additional Asian carp species as injurious under the Lacey
Act (H.R. 48, H.R. 3173, 5. 237, 5. 1421), and to direct various federal agencies to take specific
actions to increase control over and restrict the spread of Asian carp (H.R. 51, H.R. 4472, 5. 237,
5. 2946).

Congressional Research Service