carp a threat to Great Lakes
Electricity, bubbles and sound used
to fight fish that could have devastating effect on ecosystem
The newest threat to the Great
Lakes is a fish that can grow up to 4 feet long, weigh
up to 100 pounds and leap 6 to 10 feet out of the water.
With its voracious appetite,
it has the potential to eat all available food in the
lakes and starve other fish species, significantly altering
the natural ecosystem.
This invader, now the target
of a high-stakes environmental battle, is the Asian carp.
Since the early 1980s, the
fish -- actually four different species -- have been moving
up the Mississippi River after escaping from farms in
the South. Asian carp are now believed to be less than
50 miles from Lake Michigan.
``It's scary, very scary,''
said Lake Erie expert Roger Thoma of the Ohio Environmental
Once invaders like the Asian
carp get into the Great Lakes, Thoma said, getting rid
of them is impossible.
The fear is that the invasive
carp could become the dominant fish species in the lakes
and hurt commercial and sport fishing for salmon, walleye
and yellow perch.
Ohio Gov. Bob Taft has called
for ``increased attention, action and funding'' to fight
They pose ``a threat that
will ultimately lead to potentially overwhelming economic
and ecological losses,'' Taft said. ``Changes occurring
within the Great Lakes often have significant and lasting
effects, so action on this issue must be done quickly.''
For the past eight months,
the U.S. Army Corps of Engineers has been operating an
underwater electric barrier on the Chicago Ship and Sanitary
Canal, which connects Lake Michigan to the Mississippi
via the Illinois River.
The barrier is designed to
keep the Asian carp from getting into Lake Michigan and
eventually the other Great Lakes.
Joel Brammeier of the Lake
Michigan Federation, a Chicago-based eco-group, said the
carp are believed to be within 15 miles of the electric
barrier at Romeoville, Ill., and perhaps 45 miles from
``The potential damage is
so great that it's not worth taking the risk of doing
nothing,'' Brammeier said. ``That's not an option.''
The fish-shocking barrier,
which began operating last spring, cost $2.2 million to
construct, said Beldon McPheron, a spokesman for the Corps
of Engineers. Annual operating costs are about $150,000,
in addition to $84,000 for electricity and $100,000 for
McPheron said the barrier
was designed as a demonstration project to last three
years and a more permanent solution is needed.
Preliminary work has begun
on a second barrier designed to last 20 to 30 years, he
said. It will likely cost $6.5 million, McPheron said.
This barrier would remove
oxygen from the water and use sound and bubble walls to
deter the fish, in addition to the electric shock.
The University of Illinois
and the Illinois Department of Natural Resources currently
are conducting tests to determine how successful the electric
It provides a graduated electric
shock to fish. The closer they get to the underwater barrier,
the stronger the shock.
Some wildlife experts, however,
feel that electrical barriers are little more than a delaying
action and that the best remedy is to permanently cut
off the connection from the Chicago Ship and Sanitary
Canal to Lake Michigan.
But that proposal is generally
considered a long-shot solution because the canal is used
for sewage disposal and by boaters.
The canal was built in 1900
to reverse the flow of the South Branch of the Chicago
River away from Lake Michigan. That enabled Chicago to
send its sewage to the Illinois River.
The species of invading carp
are the bighead, silver, grass and black. But most of
the concern surrounds the bighead and silver carp.
These carp, from eastern China,
were added to catfish farms in the early 1970s to control
algae and snails. During floods in the early 1980s, the
fish escaped into streams in Arkansas and other Southern
They have been heading north
up the Mississippi at a rate of about 50 miles a year.
They also are found in the Ohio, Missouri and Illinois
On those rivers, Asian carp
have taken over some pools, crowding out other species.
Bighead and silver carp are
voracious filter feeders and eat algae and small animals
that are the basis of the Great Lakes food chain. They
eat up to 40 percent of their body weight every day.
There is little market for
the invading carp. Asians eat them, but they want the
fish kept alive until just before it is cooked.
Two bighead carp already have
been caught in Lake Erie. One was a 50-pounder netted
in 2000 by researchers from Ontario's Guelph University.
One was found in a fountain next to Lake Ontario in Toronto.
Most experts think that people released those fish into
Lake Erie is still reeling
from the effects of another invasive species -- the zebra
mussel, a fingernail-sized mollusk from Eastern Europe.
Found in the lake in 1988, the zebra mussel likely hitched
a ride in the ballast water of ocean-going freighters
that sailed into the Great Lakes.
``We don't know what the impacts
would be of the Asian carp,'' said the Ohio EPA's Thoma.
``We can only speculate. But there is a lot of concern,
a lot of concern.''