Opponents also have claimed falsely that it’s too late to keep the carp out
of the lakes, or they can’t survive in the lakes because of inadequate food
and spawning habitat, or even if they do spread in the lakes they won’t do
much damage, the scientists said. Their article in the Journal of Great
Lakes Research urges Congress to approve legislation ordering the Army Corps
of Engineers to quicken a study of whether to divide the two freshwater
basins, now due for completion in 2015.
“The task at hand needs to be not if, but how to solve the problem,” said
Jerry Rasmussen, a consultant and retired U.S. Fish and Wildlife Service
invasive species expert.
Other authors of the paper included Richard Sparks of the National Great
Rivers Research and Education Center in Godfrey, Ill.; William Taylor, a
Michigan State University fisheries specialist; and Henry Regier, a Great
Lakes scientist at the University of Toronto.
Mark Biel, chairman of a business and industry coalition called UnLock Our
Jobs that the scientists singled out for criticism, said their article was
“The issues this report claims to address have been asked and answered
repeatedly,” Biel said. “It’s time we move on to maintaining and improving
current barriers as well as implementing comprehensive solutions across the
region. Separation simply isn’t one of them.”
His group contends that dividing the basins or closing shipping locks would
cost billions and devastate a regional economy that depends on movement of
cargo on northern Illinois waterways.
Asian carp are voracious filter feeders that can reach 4 feet long and 100
pounds. Imported decades ago to gobble algae from Deep South fish farms and
sewage treatment plants, they escaped into the Mississippi and have moved
northward since. An electric barrier network on the Chicago Sanitary and
Ship Canal about 25 miles from Lake Michigan is designed to bock their path.
State and federal agencies are using other methods to keep Asian carp out of
the lakes, including stepped-up commercial fishing.
Rasmussen and his colleagues conducted no independent research for their
paper but drew on reports by other scientists, including University of Notre
Dame specialists who have reported detecting Asian carp DNA beyond the
The paper said the barrier, while helpful, isn’t strong enough to kill fish
and cannot prevent downstream movement of fish eggs, larvae, invertebrates,
parasites and bacteria. Studies also show that Asian carp would find
abundant food in the Great Lakes, including the nuisance algae cladophora,
and can survive throughout the region, they said.
“The Asian carp are going to whack the tributaries,” Taylor said. “They will
change the food web and dominate our streams and nearshore regions in the
Great Lakes basin.”
While attention has focused on Asian carp’s threat to the lakes, the
Mississippi basin may be even more vulnerable to species moving southward,
the paper said. The ecologically diverse river’s 260 fish species could be
crowded out by newcomers from the Great Lakes such as the round goby, it
Placing a physical barrier between the two basins is the surest method of
protecting them, Rasmussen said. But because it would be costly and take
years to build, authorities should consider buying time with short-term
measures such as creating hot-water pools or reducing oxygen levels in
sections of the Chicago waterways to kill migrating organisms, he said.
“The longer you wait, the more species cross,” Sparks said.