HAVANA, Ill – As scientists aboard a research boat activate an electric current, the calm Illinois River transforms into a roiling, silvery mass. Asian carp by the dozen hurtle from the water as if shot from a gun, soaring in graceful arcs before plunging beneath the surface with splashes resembling tiny geysers. These fish aren’t the normal species of fish you would see around here. When brought to the Great Lakes these fish have the potential to destroy the ecosystem the normal fish and organisms live in. We need to prevent the Asian Carp from getting into the Great Lakes so we can preserve its ecosystem and habitat to the organisms that already live there.
Asian carp is a catchall name for species of silver, bighead, grass, and black carp from Southeast Asia. The huge, hard-headed silver carp also pose a threat to boaters. The fish can leap out of the water when startled by boat engines, often colliding with people and causing injuries. As very big filter feeders, Asian carp consume up to 20% of their bodyweight per day in plankton and can grow to over 100 pounds. Plankton are small floating organisms that form the foundation of the aquatic food chain and are vital to native fish. It is crucial to prevent Asian carp from entering the Great Lakes. Once established in an ecosystem they are virtually impossible to get rid of. Adult Asian carp have no natural predators in North America and females lay approximately half a million eggs each time they spawn.
Asian carp were imported into the U.S. in the 1970s to filter pond water in fish farms in Arkansas. Flooding allowed them to escape and establish reproducing populations in the wild by the early 1980s. At present, bighead carp have been found in the open waters of 23 states and silver carp in 17 states. Asian carp represent over 97% of the biomass in portions of the Illinois and Mississippi Rivers and are quickly spreading northward up the Illinois River in the direction of the Great Lakes.
Asian carp are advancing towards the Great Lakes at multiple locations. The Chicago Area Waterways System, a series of sewage and shipping canals, is the pathway of greatest concern for Asian carp to enter the Great Lakes. The U.S. Army Corps of Engineers maintains three electric barriers to prevent Asian carp from entering Lake Michigan, but these barriers are only temporary impediments and have proven to be penetrable. A live bighead carp was discovered only 6 miles from Lake Michigan near Chicago. One bighead carp was found in the Chicago Sanitary and Ship Canal, just below the first electric barrier. DNA evidence has been found in multiple locations on the Lake Michigan side of the barriers. Asian carp eggs, fry and fingerlings were found in the Wabash River in Indiana. There is big risk of the Wabash River flooding into the Maumee River, which leads directly into Lake Erie.
Temperatures in the Great Lakes are well within the fishes’ native climate range. Parts of the Great Lakes, including nutrient-rich bays, tributaries and other near-shore areas, would offer Asian carp an abundant supply of their preferred food, plankton. Plankton is also favored by most young and many adult native fishes and the carp would likely strip the food web of this essential resource. The U.S. Geological Survey has identified 22 rivers in the U.S. portion of the Great Lakes that would provide suitable spawning habitat for Asian carp.
As DNA confirms the presence of Asian carp within miles of Lake Michigan, the millions of people that live and work in the Great Lakes region stand strong in their commitment to protect the Great Lakes. For more than a decade, the Great Lakes region has been constructing a fortress around the lakes to ward off the invasion of Asian carp.
While efforts during the previous decade have been valiant, much more needs to be done to ensure the Great Lakes remain safe from this invader. The Great Lakes have been under attack by more than 180 invasive species, and the impact of Asian carp could be quite severe. Asian carp can grow as large as 4 feet long and 100 pounds, and eat up to 5-10% of their body weight each day in plankton, the base of the Great Lakes’ food web. Asian carp are like zebra mussels, which also prey on the base of aquatic food webs, and can then reorganize nutrient and energy flow with unpredictable consequences on native species.
In some areas of the Mississippi River basin where these fish have steadily taken over, they now comprise up to 97% of fish biomass. Today, commercial fishers in the Illinois River regularly catch more than 25,000 pounds of Asian carp each day, an alarmingly large amount of fish. If Asian carp enter the Great Lakes, they could severely damage the $7-billion fishery. The fortress must be made stronger to keep these fish from destroying an already vulnerable ecosystem.
The Chicago Waterway System, a series of canals and rivers in and near Chicago, artificially connects the Great Lakes and Mississippi River basins. Invasive species such as zebra mussels have moved freely between the two basins through the artificial connection. Electrical barriers that are currently in place are a short-term solution to holding back Asian carp and other future invaders. Separation of the two basins is the only long-term solution to ensure Asian carp and other invaders are prevented from moving between the two basins. The Alliance for the Great Lakes, with funding conducted a study to evaluate the possibility of permanently separating the two basins, and concluded that permanent separation was possible and advisable, and also had many secondary benefits, such as improved wastewater management and transportation.
The Water Resources Development Act of 2007 authorized the U.S. Army Corps of Engineers to conduct a study examining all possible links between the two basins and to evaluate a range of options to prevent movement of species. Unfortunately, this study is expected to take years to complete. Recognizing the need to keep this study, Senators and government officials released the “Stop Asian Carp Act” early last spring. This bill requires completion, within 1.5 years, of an action plan to outline the best means of achieving ecological separation of the two basins.
The battle against invasive species has been raging for decades. The Great Lakes ecosystem has withstood many attacks, some of which have caused permanent, irreversible changes in Great Lakes food webs. Considerable effort has been made to protect the basin from future invasions, but the threat of Asian carp and other future invaders remains. Ecological separation of the Great Lakes from the Mississippi River basin is a critical step to defend our Great Lakes. We need to protect the Great Lakes and the species in ecosystem it houses to numerous organisms. The Asian Carp can be stopped, but only with people’s involvement in supporting and spreading the idea of it to protect the Great Lakes!