* Asian carp DNA found beyond barriers meant to block fish
* Great Lakes ecosystem at risk from invasive carp
* U.S. authorities weighing options, look for carp
By Andrew Stern
CHICAGO, Nov 20 There are signs Asian carp may
have breached barriers designed to keep the prolific fish out
of the Great Lakes, which could spell ecological disaster for
the vital source of fresh water, authorities said on Friday.
Concentrations of DNA discovered by Notre Dame University
researchers may indicate the presence of bighead and silver
carp upstream from two electrical barriers designed to bottle
up the invasive fish.
Environmentalists say that if the fish reach the Great
Lakes, about 20 miles (32 km) from the barriers, they would
quickly destroy the lakes' $4.5 billion fishery by consuming
other fish and their food sources. Only Lake Superior among the
five lakes may be too cold for the carp, which can reproduce
rapidly and reach 100 pounds (45 kg).
The Great Lakes are the world's largest body of surface
fresh water and are relied on by 30 million people in the
United States and Canada for drinking water and recreation.
"This is devastating news," Andy Buchsbaum of the National
Wildlife Federation said of the discovery of carp DNA in the
Cal-Sag channel 8 miles (13 km) from Lake Michigan.
"We have to hope that there aren't enough population of
fish to reproduce and create an epidemic of Asian carp in the
lakes," he said.
The barriers are on the Chicago Sanitary Ship Canal, which
is fed by several waterways that flow away from Lake Michigan.
The canal is connected by various rivers to the Mississippi
Two electrical barriers constructed in recent years in the
canal near Chicago were designed to shock the carp and keep
them out of the lake.
The DNA could be from carp feces or eggs carried by ship
and barge traffic, but it could indicate the carp have breached
the barriers, Buchsbaum said.
Environmentalists called for the immediate closing of
several locks separating the lakes from the inland waterways,
and pressed for a permanent solution that would separate the
Great Lakes from the Mississippi River watershed.
"Right now we have a last shot at keeping these carp out of
Lake Michigan, and that's to close the locks," said Joel
Brammeier of Alliance for the Great Lakes, an environmental
The U.S. Army Corps of Engineers said it and other agencies
had met since Wednesday to consider the best course of action.
Authorities will be sampling the channel to try to locate any
"We're not discounting any options," which could include
shutting the locks, a spokesman for the Corps of Engineers
The waterways are used by barges serving steel plants and
other industry in the area. The lock separating the Chicago
River from Lake Michigan would also be affected, although tour
and pleasure boat traffic is down because of the season.
The invasive bighead and silver carp have come to dominate
the Mississippi River watershed that is linked to Lake Michigan
by a network of canals.
The carp were introduced into the Southern United States in
the 1970s to help clean man-made fish farms. They escaped into
the Mississippi River during flooding two decades later.
The omnivorous fish -- which are known to injure boaters
because they often leap out of the water at the sound of a
passing motor -- make up 95 percent of the biomass in sections
of the Illinois River.
The Corps of Engineers said it would go ahead with planned
maintenance on one of the two barriers beginning on Dec. 2. As
part of the maintenance project, authorities will bar ship
traffic and introduce a fish poison, rotenone, into several
miles (km) of the Chicago Sanitary Ship Canal downstream from
the barriers to kill all fish, including the carp.
(Editing by Peter Cooney)