The Great Lakes are currently facing a significant threat from invasive carp.
Decades ago, four species of Asian carp were brought to the U.S. to control weeds in aquaculture and sewage treatment operations. But escaped fish have migrated up the Mississippi River and into its tributaries. And Asian carp are now competing with native fish, eliminating vast areas of aquatic plants, and reducing water quality.
But it is their potential threat to the $7 billion a year Great Lakes fishing industry that is causing the most alarm. Asian carp have been found in the Illinois River, which connects the Mississippi River to Lake Michigan. The Obama administration has spent $200 million over the past four years in an effort to keep the fish from reaching the Great Lakes.
One of the main efforts has been an underwater electric barrier – located in the Chicago Sanitary and Ship Canal – that emits electric pulses that repel fish. But critics note that dozens of water samples taken beyond the barrier have shown evidence of Asian carp DNA.
Some argue the only way to prevent Asian carp from invading is to construct a physical barrier that separates the Great Lakes and Mississippi River basin. Adding to the problem, silver carp, one of the invading species, are remarkably adept at jumping over barriers, including low dams.
The U.S. Army Corps of Engineers has committed to developing a short list of control options by the end of the year – but an effective solution may take years to implement and could cost billions of dollars.
Let’s hope it’s not too late.
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Web Links
Invasion USA: Asian Carp Invaders Have Taken the Mississippi, Are the Great Lakes Next?
http://www.scientificamerican.com/article.cfm?id=asian-carp-woes
Asian Carp Overview
http://www.nps.gov/miss/naturescience/ascarpover.htm
Asian Carp
http://www.youtube.com/watch?v=qfG4vsJ5_xI
Photo, taken on July 6, 2010, courtesy of Louisville USACE via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.