TRAVERSE CITY, Mich. (AP) – The U.S. Army Corps of Engineers has
fired up a new electric fish barrier on a Chicago-area waterway
linking the Great Lakes and Mississippi River watersheds, the
latest bid to protect the lakes from an Asian carp onslaught that
could harm native species.
The $19 million device is slightly upstream from two others on
the Chicago Sanitary and Ship Canal, which could serve as a pathway
to Lake Michigan for bighead and silver carp that have migrated
northward on the Mississippi and its tributaries since the early
1970s. The underwater electrodes emit rapid pulses, creating a
force field meant to repel fish or shock those that don’t turn
“We now have great flexibility and redundancy” in the barrier
network, said Col. Vincent Quarles, commander of the Army Corps’
Chicago district. “We want to deter the Asian carp threat. The
barrier is a very good tool.”
The three barriers are within a 1,500-foot section of the canal
about 25 miles south of Chicago. The first, then a demonstration
project, went online in 2002. The second was activated in 2009.
Federal and state officials contend the barriers have performed
well, preventing Asian carp from becoming established in Lake
Michigan and spreading to the other lakes. Biologists say the
voracious carp, which can reach 4 feet in length and weigh up to
100 pounds, could disrupt the food web by out-competing less
aggressive fish for plankton, eventually threatening the lakes’ $7
billion fishing industry.
Skeptics question the barrier’s effectiveness. Scientists with
the University of Notre Dame and The Nature Conservancy have
reported detecting bighead and silver carp DNA in numerous
locations above the barrier, although just one live Asian carp has
been found there.
“There are still serious gaps in our knowledge about how well
it’s working,” said Thom Cmar, an attorney with the Natural
Resources Defense Council. “No one ever imagined these electric
barriers would be a permanent solution. They’ve always been just a
Environmental groups have called for physically severing the
century-old, man-made link between the Great Lakes and Mississippi
drainage basins, a step also sought by Michigan and four other
Great Lakes states in a pending federal lawsuit against the Army
The Corps has pledged to consider that option in a comprehensive
study of ways to prevent species migrations between the two
watersheds, but critics are unhappy that it isn’t scheduled for
completion until 2015.
In a report last week, the Corps acknowledged the 2 volts per
inch of electricity coursing through the barriers might not be
enough to turn back fish just a few inches long, although it
appears sufficient for larger fish. Officials said they would
continue studying whether the voltage could be increased without
endangering barges moving flammable items across the canal. Results
are expected this fall, Quarles said.
With the new barrier up and running, Quarles said the second
would be taken down for maintenance within the next two months.
Field studies will determine how many of the devices will be
operated at any given time, he said.