No traces of Asian carp found in Milwaukee waterways
The researchers notified the Wisconsin Department of Natural Resources of the results in a letter last week. The DNR provided boats and boat operators to help collect the water samples from the Milwaukee, Menomonee, and Kinnickinnic rivers and nearby creeks and ponds in November 2010.
“The great news is that all samples were negative for the presence of Asian carp DNA,” says Bob Wakeman, aquatic invasive species coordinator for the Wisconsin Department of Natural Resources.
Wakeman says the results are also an important contribution to the baseline information we’re gathering on aquatic invasive species within the state.”
Last January, the Notre Dame researchers had identified for the first time in Lake Michigan genetic material from Asian carp. The DNA was found in water samples collected from Calumet Harbor on the lake, near the Illinois-Indiana border, with a second DNA match turning up in the Calumet River in Illinois, within a half-mile of the lake.
Those earlier findings raised concerns that the carp had found its way beyond the barrier system built to prevent the fish from entering the Great Lakes.
The new sampling was conducted and analyzed by the University of Notre Dame. The U.S. Fish and Wildlife Service provided funding for the sampling through the Great Lakes Restoration Initiative.
Mike Staggs, DNR’s fisheries director, says these new results are great news, “but all the more reason to make sure we block access from the Mississippi River now. Asian carp have the potential to be a serious threat to our Great Lakes fisheries and ecosystem.”
An estimated 235,000 anglers fish 3.7 million days every year for fish in Wisconsin’s waters of Lake Michigan and Lake Superior, Staggs says. They caught 766,000 fish in 2008, and generated an economic impact of $419 million. Wisconsin’s Great Lakes waters also support commercial fisheries.
There are three species of Asian carp that are considered invasive and a threat to the Great Lakes — the bighead, silver and black carp — because of their feeding and spawning capabilities. Bighead carp are capable of consuming 20 percent of their own body weight in food each day, and so compete with other fish and aquatic organisms for food. Silver carp are smaller, but pose a greater danger to recreational users because of their tendency to jump out of the water when disturbed by boat motors. They can severely impact fishing and recreation. They can spawn multiple times during each season and quickly out-compete native species by disrupting the food chain everywhere they go.
Asian carp were imported to the southern United States to help keep aquaculture and wastewater treatment retention ponds clean, Staggs says. Flooding in the 1990s allowed them to spread to the Mississippi River basin and other large rivers. They have been found occasionally in Wisconsin waters of the Mississippi River, but are not established or abundant in them. Now, these invaders are in the Chicago Sanitary and Ship Canal, built over a century ago to artificially connect Lake Michigan to the Mississippi River basin.