The Asian Carp is a huge fish that’s native to China. It was brought over from China and during the Great Flood of 1993 escaped from farm ponds and got into the Mississippi River. The Asian Carp competes with native fish and destroys their habitat. Researchers worry that if the Asian Carp gets into the Great Lakes, it could damage the lakes’ ecosystems. Some scientists believe that the threat of this invasive fish to the Great Lakes fishing industry is great enough to take drastic measures. One proposal would kill part of a river that connects the Mississippi River System to the Great Lakes. The Great Lakes Radio Consortium’s Annie MacDowell reports:
The Asian Carp is a huge fish that’s native to China. It was brought over from China and
during the Great Flood of 1993 escaped from farm ponds and got into the Mississippi
River. The Asian Carp competes with native fish and destroys their habitat. Researchers
worry that if the Asian Carp gets into the Great Lakes, it could damage the lakes’
ecosystems. Some scientists believe that the threat of this invasive fish to the Great
Lakes fishing industry is great enough to take drastic measures. One proposal would kill
part of a river that connects the Mississippi River System to the Great Lakes. The Great
Lakes Radio Consortium’s Annie MacDowell reports:
Since late in the 19th century until now, Chicagoans have spent billions of dollars to
clean up their water. Untreated sewage used to flow into the Chicago River and was
carried into Lake Michigan, where the city got its drinking water.
In the summer of 1885, 12 percent of the population of Chicago died of cholera and
other diseases because of fouled water.
Phil Moy is with the Wisconsin Sea Grant. He says before modern-day sewage treatment
plants, the river was a cesspool.
“You go back far enough, like before there was really even much more than primary
treatment… you had cattle carcasses and all sorts of nasty things floating and actually in
the river itself.”
More than a century ago, city planners decided to reverse the flow of the Chicago River,
to protect people’s health. This involved digging a larger and deeper canal that connected
the Mississippi River system to the Great Lakes. From then on, sewage dumped in the
Chicago River flowed downstream instead of into the lake. Chicagoans’ water supply
was no longer tainted, but the project opened up a way for fish and other species to travel
between the rivers and the Great Lakes. So Chicago’s efforts to clean up the sewage back
then, has caused unintended consequences a century later.
Now scientists are trying to find ways to stop exotic species that have invaded the
Mississippi from getting into the Great Lakes and exotic species that have invaded the
Great Lakes from getting into the Mississippi. Ships and barges use the canal to transport
goods, so putting up a physical barrier wouldn’t work. For now, the government has
spent more than a million dollars on an electric barrier that repels the fish, but they need a
second electric barrier for extra protection. However, more money from the government
to build the second barrier has been slow in coming.
So in the interim, some experts have come up with an idea… a temporary solution that
flies in the face of the Clean Water Act. They want to pollute the river again.
Jerry Rasmussen is with the Mississippi Inter-State Cooperative Resource Association.
The group tries to coordinate states’ efforts to protect the river system. Rasmussen says
creating a dead zone could be done easily and at low cost.
“Probably the least expensive thing to do in this situation would be shutting down some
of the treatments. It would be a cost effective measure, certainly in the interim.”
Rasmussen says the first step would be to shut off the aerators.
South of Chicago, along part of the canal that connects the Chicago River to the
Mississippi River system, an inoperative aerator sits alongside the water. It’s not needed
in the wintertime, because there’s enough oxygen in the water during the cold months.
During the summertime, the aerators are turned on to help keep the river healthy. But
Irwin Polls of the Metropolitan Water Reclamation District says shutting off the aerators
alone during the summer would not reduce the oxygen level enough to be lethal to the
“Keep in mind, in the early fifties and in the nineteen-sixties, before supplemental
aeration, before the treatment plants were upgraded, the primary fish species in these
waterways were carp and goldfish which could survive at lower oxygen levels than we
So if common carp could survive the lower oxygen levels, maybe Asian Carp could, too.
If shutting off the aerators isn’t enough to degrade the river’s water quality, things could
Jerry Rasmussen says releasing more sewage waste into the river by omitting the final
stage of waste treatment could be enough to create the dead zone. If not, Rasmussen says
chemicals would need to be added to make the water more toxic. Irwin Polls says this is
a bad idea.
“The kind of chemicals they’re talking about are hazardous. Over one and a half billion
gallons of treated sewage enters this system every day so you’d have to kind of add
enough material to dilute the system that you have in there so we’re talking about large
volumes, continuously, of toxic compounds. So it would be in violation of the law, the
federal laws, as far as introducing toxic compounds and the cost I think would be
astronomical, because the volume of water is tremendous.”
Breaking federal law is the major obstacle to implementing the dead zone plan. To
violate the Clean Water Act, scientists would have to get the support of the Mayor of
Chicago, the Illinois Governor, the U.S. Environmental Protection Agency, and
ultimately the President.
But some scientists believe they’ve got to do something now to stop the Asian Carp.
They’re worried the carp might get into Lake Michigan while they wait to get enough
government money to make repairs on the existing electric barrier, and to buy and install
the second. They hope to have the second line of defense in place in a year. A meeting
with government leaders and experts on invasive species has been scheduled for
sometime in May. That’s when the plan’s supporters will try to convince policy-makers
to kill part of the river.
For the Great Lakes Radio Consortium, I’m Annie MacDowell.