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Invasive Asian carp on verge of entering Great Lakes

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Well that didn't take long: Just six months after the U.S. Supreme Court turned down requests to close the locks between Chicago area waterways and Lake Michigan to stop the spread of invasive Asian carp the giant, voracious fish has almost made its way to the Great Lakes.

Last week, a one-meter-long, nine-kilogram bighead carp (pictured) was found in Lake Calumet, along the Chicago Area Waterway System (CAWS), just six miles from Lake Michigan. According to the Asian Carp Regional Coordinating Committee, this is the first carp that has been found in the CAWS above the U.S. Army Corps of Engineer's Electric Barrier System, a system put in place to try to control the spread of the fish.

According to the U.S. Environmental Protection Agency, Asian bighead (Hypophthalmichthys nobilis) and silver (H. molitrix) carp were imported into the U.S. in the 1970s as a method for removing algae from catfish farms. But flooding in the 1990s overflowed farming ponds and sent the fish into the Mississippi River where they have managed to outcompete, outbreed and out-eat local species.


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In response to last week's discovery, several lawmakers are calling on the Obama administration to temporarily close the Chicago locks and come up with a permanent barrier to stop the piscine gate crashers' further advance. "For the sake of the region's economy and ecosystem, I urge you to take immediate action to stop the spread of this species into the Great Lakes and consider the possibility of permanent hydrological separation," wrote Sen. Kirsten Gillibrand (D–N.Y.) in a letter to the U.S. Fish and Wildlife Service and other agencies.

Sen. Dick Durbin (D–Ill.) called the discovery of the carp in Lake Calumet a "game changer" and a "wake-up alarm."

Henry Henderson, Midwest program director for the Natural Resources Defense Council, warns in his blog, "Like cockroaches skittering across a bathroom floor, when you net one Asian carp, you can bet that there are plenty more where that one came from."

In January Michigan Gov. Jennifer Granholm (D) said in a prepared statement, "We cannot allow carp into the Great Lakes. It will destroy our Great Lakes fisheries, the economy." The commercial fishing industry in the Great Lakes is worth more than $7 billion a year. But closing the locks to protect the Great Lakes creates a different set of economic headaches: They are vital to commercial shipping throughout the Great Lakes region.

Photo courtesy of the Asian Carp Regional Coordinating Committee