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GLIN==> Asian carp, invasive species

Posted on behalf of Irene Miles <miles@uiuc.edu>

Asian carp, invasive species
July 19, 2002

Source:   Mark Pegg (309)543-6000
Contact:  Irene Miles
Extension Communications Specialist
(217)333-8055; miles@uiuc.edu

Electric Barrier May Stop Asian Carp

URBANA--The electric barrier in the Chicago Sanitary and Ship Canal may
effectively prevent Asian carp from entering Lake Michigan, according to
preliminary research results.  In the early stages of an Illinois-Indiana
Sea Grant-funded study, researchers found that more than 99 percent of
bighead carp were deterred by a simulated electric barrier modeled after the
actual one.

Using fish raceways to do controlled experiments, John Chick and Mark Pegg
of the Illinois Natural History Survey are testing the potential
effectiveness of the present electric barrier, as well as exploring
additional barrier technologies as they relate to Asian carp. Two species of
Asian carp, bighead and silver, are migrating closer to the actual barrier
site, located near Romeoville, Illinois, and have been spotted as close as
25 miles from Lake Michigan.

Thus far in the study, there were 381 attempts by bighead carp to pass
through the simulated barrier--379 times the fish turned around. Only one
fish went through the barrier, and in fact, did it twice.

"This was a smaller carp, which was not surprising. Smaller fish are less
susceptible to the electric current," said Pegg. These tests were done for
six continuous hours per day for three days.

Asian carp, which have grown to 50 pounds in U.S. waters, were brought here
for use in aquaculture in the 1970s, and escaped into the Upper Mississippi
River System. The populations of these species have increased dramatically
in some areas.

"Asian carp consume zooplankton, which all fishes typically feed on in their
juvenile stages, so they have the potential to adversely affect every
species of fish in the Mississippi River and Great Lakes," said Pegg.

The electric barrier was turned on in April in an effort to stop non-native
fish from moving between the Great Lakes and the Mississippi River basin.
The idea is that as fish pass through the barrier, they feel increasing
levels of electricity, which leads them to turn around. "Because the 60-feet
wide barrier is not as strong higher up in the water column where Asian carp
are typically found, there has been some concern that the electric field may
not effectively repel the fish," said Pegg.

Recently, the International Joint Commission has recommended that a second
barrier be installed as a backup to ensure that the carp and any other
invasive fish species are stopped. And, Chicago Mayor Richard Daley has
asked Congress for funding to strengthen the electric barrier and to study
ways to keep invasive species from entering the Great Lakes.

Next, Chick and Pegg will explore different scenarios using the present
electric barrier technology, varying the strength and width of the electric
pulse within the recommended safety guidelines. They will also experiment
with other barrier methods including "fish guidance systems" that use sound
and a "wall of bubbles." "We will test the effectiveness of these
technologies and then try them in combination. Perhaps the fish can become
used to one or the other, but in combination, they may prove successful,"
added Pegg. They will also test the effectiveness of these technologies in
augmenting the electric barrier.

Carp have been migrating on their own towards Lake Michigan, but there is
also a risk that anglers and others who harvest and fish with wild bait may
inadvertently transport these species. "When minnows are harvested for bait,
smaller or newly-hatched carp may tag along," explained Pegg.

There are precautions that anglers can take to reduce the risk of spreading
exotic species, such as the Asian carp. "Never dispose of your bait by
putting it into a waterbody," said Pat Charlebois, Illinois-Indiana Sea
Grant biological resource specialist. "Throw unused bait away on land or in
the trash."

If you are fishing with wild bait, use it on the water body from which it
was collected. And you can also learn to identify Asian carp. To obtain a
U.S. Fish and Wildlife Service brochure on the Asian carp, call
608-783-8434. You can also contact Charlebois at 847-872-0140. For more
information on invasive species, visit the Sea Grant Web site at


The Illinois-Indiana Sea Grant College Program is one of 30 National Sea
Grant College Programs.  Created by Congress in 1966, Sea Grant combines
university, government, business and industry expertise to address coastal
and Great Lakes needs.  Funding is provided by the National Oceanic
Atmospheric Administration (NOAA), U. S. Department of Commerce, Purdue
University at West Lafayette, Indiana, and the University of Illinois at

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