Scientists favor dividing Great Lakes, Mississippi River
TRAVERSE CITY, Mich. (AP) – No additional study
is necessary to prove that separating the Great Lakes and the
Mississippi River systems is the only way to prevent invasive
species such as Asian carp from migrating between them and doing
serious ecological and economic harm, a team of scientists said
In a newly released paper, the scientists said opponents of
severing the man-made link between the two watersheds were
spreading myths, including that electric barriers are enough to
stop the unwanted carp from entering Lake Michigan through a
Chicago-area shipping canal.
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 biased.
“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 electric barrier.
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 said.
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