Asian carp were imported in the 1970s to cleanse Deep South aquaculture and sewage treatment ponds.
The DNA that was found there was more than 100 miles from waterways infested with Asian carp.
As Illinois waters became clogged with the invasive Asian carp, Schafer saw opportunity where others saw environmental disaster.
The Wabash is "probably the smallest river in which we are aware of Asian carp spawning, " Chapman said.
State and federal experts are studying whether the DNA could have come from sources other than Asian carp.
Among the victims: Mississippi and Arkansas catfish farmers who kept Asian carp in their ponds to control algae blooms.
The DNR estimates 56 million pounds of Asian carp swim in the Illinois.
"I would say there's at least some evidence for Asian carp being present in southern Lake Michigan, " Jerde said.
Ironically, while Asian carp are spreading rapidly in the U.S., they're declining in China, where dam projects are reducing their habitat.
But scientists in recent years have detected DNA from Asian carp in waterways beyond the barrier, sparking debate over its effectiveness.
But scientists have detected Asian carp DNA in dozens of water samples collected farther upstream, some just a few miles from Lake Michigan.
The DNR said the report reflects the most rigorous study of Asian carp DNA evidence in Minnesota to date, according to the St.
But while the government team acknowledges the presence of Asian carp genetic fingerprints, it disagrees that they necessarily signal the presence of live fish.
Kelly Baerwaldt, a fisheries biologist and Asian carp program manager for the Army Corps who supports the alternative-source theory, said the new report didn't change her mind.
On the Illinois River in Peoria anglers armed with bows and arrows hunt Asian carp that leap high in the air, agitated by the sound of boat engines.
But the Jerde team's paper, published online Thursday by the Canadian Journal of Fisheries and Aquatic Sciences, argues that the likeliest explanation remains the presence of live Asian carp.
The paper summarizes findings by Jerde and other scientists from Notre Dame, The Nature Conservancy and Central Michigan University during two years of searching the Great Lakes basin for Asian carp.
Marc Miller, director of the Illinois Department of Natural Resources, said his state had arranged for commercial fishermen to harvest 700 tons of Asian carp on the Illinois River in recent years.
Michigan, Wisconsin, Ohio, Minnesota and Pennsylvania filed an unsuccessful federal lawsuit against Illinois over a Chicago-area network of canals and rivers that could provide a pathway to Lake Michigan for Asian carp.
In Chicago, chefs have turned Asian carp into ceviche and chowder in an attempt to curb the rise of the plankton-devouring species, which has spread to Great Lakes since escaping from US fish farms in the 1970s.
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Scientists with the Coast Guard Research and Development Center and the U.S. Environmental Protection Agency conducted experiments in a section of the Illinois River called the La Grange Reach, where Asian carp are well established.
The Asian carp is a species not native to this part of the world, and its presence in the Great Lakes would be devastating to the species that are native to Lake Michigan and its counterpart lakes.
Gov. Pat Quinn today signed an agreement with China to export as much as 30 million pounds of Asian carp a year from the Illinois River, a move aimed at reducing the population of the invasive species downstate.
The Purdue team, assisted by the Indiana Department of Natural Resources and the U.S. Geological Survey, collected water samples containing Asian carp eggs in 2011 from sections of the river that were much shallower and narrower than had been considered necessary for spawning, Goforth said.
Finalists: Dan Egan of the Milwaukee Journal Sentinel for his exhaustive examination of the struggle to keep Asian carp and other invasive species from reaching the Great Lakes and ultimately all of the nation's inland waters, a story enhanced by animated graphics, and Tony Bartelme of The Post and Courier, Charleston, S.C.
Written by experts who pioneered use of genetic data to search for the aggressive fish, the paper disagrees with government scientists who say many of the positive Asian carp DNA hits recorded in or near the lakes in recent years could have come from other sources, such as excrement from birds that fed on carp in distant rivers.
Briney then chucks the Asian bighead carp onto a slimy heap of others writhing on the bottom of the boat.
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