Illinois electrifies canal to halt flow of invasive carp
By Peter Slevin
Posted on Fort Wayne.com May. 30, 2005
ROMEOVILLE, Ill. – These fish jump. Oh, how they jump.
It’s common for an Asian carp to leap four feet out of
the water and flop into whatever might rumble into its
path, be it watercraft or fisherman.
They also make a big splash. A 60-pounder is not unusual.
“Every day we go out on the water, the number of fish
we see jumping around the boat is just astounding. It’s
incomprehensible,” said Mark Pegg, a fisheries biologist
for the Illinois Natural History Survey. “You just have
to see it to realize there are that many fish jumping
Near the Illinois River, Pegg and his colleagues inspected
a 43-pound female, which he described as “a small one.”
She was carrying 2.2 million eggs, and she had plenty
“There were hundreds, if not thousands, of large females
in this one inlet we were sampling,” Pegg said.
The Asian carp is sowing fear in marine biologists and
fishermen. Descendants of the fish, imported from China
30 years ago by catfish farmers in the deep South, escaped
their pens when floodwaters rose and have been swimming
north and procreating ever since, each day consuming as
much as 50 percent of their body weight in plankton and
The danger, experts say, is that the voracious jumping
carp will overrun the waterways and other fish will starve
to death. Along the Chicago Sanitary and Ship Canal, a
gateway to the Great Lakes, government authorities hope
to shock the carp into submission.
Literally. At a construction cost of $9 million and an
annual expense of $500,000, state and federal engineers
are electrifying 500 feet of water to prevent the Asian
carp from reaching Lake Michigan. Crews are using heavy
cranes to lay 84 steel belts at the bottom of the 160-foot-wide
canal. Transformers equipped with backup generators will
juice the metal and create a pulsing electrical field.
“What we’re doing here is plugging the biggest hole.
This is something that deters the fish without killing
them,” said Charles Shea, project manager for the U.S.
Army Corps of Engineers. “We can’t make a 100 percent
guarantee, but it certainly seems unlikely any fish could
swim through this barrier.”
What about a human?
“You’d get a hell of a headache,” Shea said.
The new electrified field, scheduled to be in full buzz
by October, is modeled on a three-year-old pilot project
nearby that stretches across 55 feet of canal. The existing
zapper, believed to be the largest such fence in the world,
relies on technology used to contain the fish in fish
Researchers study its effectiveness by implanting radio
transmitters in more than 100 fish swimming in the neighborhood.
Each fish sends a unique signal.
“They test the barrier a couple of times, and they usually
go far away and don’t come back up here again,” Shea said.
“We’ve had only one fish get through.”
That fish – not an Asian carp – passed through the barrier
in the churning wash of a tug pushing a barge, Shea said.
It happened in 2002, and the transmitter soon fell to
the bottom of the 25-foot-deep canal, where it still emits
a signal. Researchers concluded that the fish did not
survive the trip.
The closest an Asian carp has been spotted to the fence
is about 20 miles, also in 2002, said Shea, who reported
that the nearest concentration is believed to be 60 miles
from the fence, which is 25 miles southwest of Chicago
and the entrance to Lake Michigan. .
Keeping Asian carp out of the Great Lakes is considered
essential at a time when countless invasive species, often
traveling in the ballast water of large ships, are changing
the environment of the world’s largest surface supply
of fresh water.
“There have been massive changes in the Great Lakes,”
said David Jude, a University of Michigan professor who
sits on the advisory committee that oversees the electrified
fence. “We sure as heck don’t need a big fish that’s coming
here, feeding on this zooplankton and competing with other
fish in the lakes.”
Illinois has invested $2 million in the fish-shocking
project, with at least half a dozen other states making
smaller contributions. The federal government committed
about $7 million.