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Asian carp discovery near Lake Michigan draws concern from wildlife experts, legislators

Illinois Department of Natural Resources/AP
A 20-pound Asian carp is held after being caught beyond the electric barriers constructed to keep the dreaded invasive species out of the Great Lakes. State and federal officials said Wednesday that commercial fishermen found the 3-foot-long, 20-pound carp in Lake Calumet on Chicago's South Side, about six miles downstream of Lake Michigan Buy this photo

BY SUZANNE JACOBS
Daily Staff Reporter
Published June 29, 2010

Though efforts have been made to keep the Bighead Asian carp at bay and out of the Great Lakes, the recent discovery of a carp beyond the electrical barrier system in place at the Chicago Area Waterway System has left many wildlife experts uneasy.

The Illinois Department of Natural Resources and the United States Fish and Wildlife Service reported the discovery of an Asian carp — an invasive species that has ravaged the Mississippi and Illinois river systems — about 6 miles downstream of Lake Michigan, according to a press release issued last week.

The IDNR has been sampling the Chicago Area Waterway System since February in search of both Bighead and Silver Asian carp. The fish caught in Lake Calumet on Jun. 22 by a commercial fisherman contracted by the IDNR measured 34.6 inches long and weighed 19.6 pounds.

John Rogner, assistant director of the IDNR, said no additional Asian carp have been found after further netting and electrofishing in the area. He said fishermen will continue to survey Lake Calumet and the Calumet River leading to Lake Michigan through this week, but even if no Asian carp are found, the threat of the invasive species’ northern migration will remain.

“One fish doesn’t necessarily mean there are more fish, but it certainly rings the alarm bell,” he said. “We will never become confident that there are none in the system. We don’t see an endpoint actually. I think (the search) will continue for a good long while.”

In the event that fishermen find more of the foreign species, Rogner said the IDNR may pursue intense fishing and adding Rotenone — a chemical toxin — in the water. He said that if implemented properly, Rotenone can effectively kill the Asian carp, while sparing other fish that are more tolerant of the toxin.

Charlie Wooley, the deputy regional director for the USFWS in Minneapolis, Minn., said it’s too soon to speculate what the IDNR and the USFWS will do if more Asian carp show up.

“If there are additional fish found … we would reconvene the technical experts, and we would design another … kind of control action in that area. What that would be, it would be too early to conjecture that right now,” he said.

Wooley did warn, however, that if there are more Asian carp above the U.S. Army Corp of Engineer’s Electrical Barrier System and they become established in the Great Lakes, there would be disastrous ecological consequences.

“They have left a trail of devastation behind them as they’ve moved through the river system. We just do not want to see that happen in Southern Lake Michigan,” he said.

The only other Asian carp found in the CAWS was caught on Dec. 3 of last year in the Chicago Sanitary and Ship Canal. Unlike the first fish, the specimen caught last week was found above the electric barrier, which was designed specifically to keep invasive aquatic species from entering the Great Lakes Basins from the Mississippi River.

According to Rogner, the electric barrier has three parts but only two of them are currently fully functional. Construction on the third will be completed in the fall, at which point, he said, the barrier will be a “very effective system.”

Although this is the first fish caught above the barrier, a research team led by David Lodge, a professor of biological sciences at the University of Notre Dame, found environmental DNA of Silver Asian carp in the Calumet River and Calumet Harbor last year, which at the time indicated the presence of the invasive species.

Last week’s catch validated Lodge’s findings and has caused great alarm among state officials.

A report from the Asian Carp Regional Coordinating Committee, a group dedicated to the control and management of Asian carp in the U.S., said fish farmers in the south imported the species in the 1970s to keep aquaculture facilities clean and provide fresh fish for markets.