Keep Asian carp out of lakes, or we will regret it
July 18, 2002
BY ERIC SHARP
Detroit Free Press
When the fight against the sea lamprey in the Great
Lakes started 50 years ago, no one dreamed the parasites
would still be destroying large numbers of lake trout,
especially after governments had spent $250 million on
Probably the most important lesson we have learned from
the lamprey mess is that once an exotic species gets established
in the Great Lakes, it's there to stay. Efforts to keep
the damage caused by sea lampreys to tolerable levels
will be unending and expensive.
By the late 1990s, it looked as if attempts to poison
lampreys and keep them out of spawning streams with electrical
barriers and raised weirs were working. But we forgot
about the St. Marys River, which turned out to be a lamprey
factory, producing so many each year that virtually every
lake trout in northern Lake Huron was killed before it
reached spawning age.
Scientists have since found ways to minimize the number
of lampreys the St. Marys and other streams churn out,
but if we ever stop those control efforts, we'll see lake
trout disappear again.
The lamprey also taught us some lessons about the politics
of controlling exotic species. And those lessons are important,
because we might be on the verge of repeating the mistakes
of the lamprey era in dealing with a new threat to the
lakes, exotic Asian carp.
Bighead and silver carp either escaped from or were
released by catfish farms in the South. In less than 10
years they have spread up the Mississippi River system
and been collected in the Chicago Sanitary and Ship Canal
only 25 miles below Lake Michigan. Some people say they
have seen them 11 miles below the lake.
About a month ago, the U.S. Army Corps of Engineers
turned on an electrical barrier in the Chicago canal designed
to keep the bighead carp at bay.
But it took so long to get the money to build and run
the barrier that no one knows if the carp, which can exceed
100 pounds, are already above it. In addition, the barrier
is an experimental project, and the money to operate it
runs out in about 18 months.
And an even more immediate problem is the lack of a
backup generator to keep the barrier going if the commercial
power supply fails.
"One power failure could jeopardize the effectiveness
of the barrier," said Mark Gaden, a spokesman for the
Great Lakes Fisheries Commission. "We've asked Congress
for funds to mediate that."
So far, Congress hasn't come through. Maybe that's because
the amount needed is too small to draw attention. A $150,000
generator could be all that's standing between the Great
Lakes and another environmental disaster, but things like
that tend to get overlooked by people who hold onto their
jobs by funneling millions or even billions of dollars
to get votes and campaign contributions.
But failure to act on these environmental threats can
be incredibly costly. Chris Goddard, executive secretary
of the fisheries commission, figures that in the past
15 years, fixing damage from zebra mussels has cost governments
and business along the Great Lakes hundred of millions
A second barrier in the Chicago canal would cost about
$350,000 to install and $100,000 a year to maintain. Even
the larger figure is a fraction of the cost of some junkets
the State Department puts on for bigwigs.
Like zebra mussels, bighead and silver carp are filter
feeders. But they also are thousands of times the size
of a zebra mussel. They don't filter plankton from open
waters but live by sucking in algae and detritus from
Asian carp aren't much use as a sport fish, and they
have the ability to root up bottom vegetation and turn
rivers and lakes into mud pits. But even scarier is that
in some of the big pools along the Mississippi, they have
multiplied so quickly that in less than a decade they
make up 90 percent or more of the fish life.
Biologists worry that a few million of them sucking
up the water of the Great Lakes could disrupt the food
chain and lead to a collapse of major sport and commercial
species like salmon, walleyes and perch.
They also worry about what would happen if bighead and
silver carp get into tributary rivers.
The truth is that no one is sure what bighead and silver
carp would do to the ecology of the Great Lakes if they
become established there. But if our experience with sea
lampreys and zebra mussels is anything to go by, we probably
don't want to find out.