Asian Carp Could Devastate Great Lakes
we act fast, the Great Lakes are about to be
invaded by giant fish so voracious, says biologist
GAIL KRANTZBERG, they'll devastate the ecosystemBy GAIL
August 26, 2002 Page A13
This is an alert to all things that live in the Great
Lakes. Beware. The voracious alien Asian carp is poised
to invade. The environmental and economic havoc that would
likely result make the problems associated with the infamous
zebra mussel pale by comparison.
Asian carp grow rapidly and have ravenous appetites.
They can reach the size of a healthy teenager, and may
be up to 50 kilograms in weight and two metres long. They
can increase by five kilograms per year, and eat half
their body weight daily. And they are extremely prolific,
with fertile females producing as many as a million eggs
Vacuuming up microscopic plants and animals, Asian carp
can compete for food with virtually every juvenile sport
and commercial fish, which forecasts widespread injury
to our multibillion-dollar fishery. If these carp enter
the Great Lakes, there is a very high probability that
the ecosystem will be hugely and irreversibly injured.
Asian carp were imported from China in the 1970s to control
pests, such as excessive algae, in Arkansas fish farms.
Scientists believe the carp escaped from the aquaculture
operations during flooding in the 1990s. Widespread in
the Mississippi and Illinois Rivers where the commercial
fisheries are reeling, they were recently found only 40
kilometres from the Chicago Sanitary and Shipping Canal,
a man-made entranceway to Lake Michigan.
There is an imminent peril that we will infect our lakes
with these fish through the Chicago Sanitary and Shipping
Canal. A marvel of engineering design, the canal opened
in 1900, reversing the flow of the south branch of the
Chicago River away from Lake Michigan, dispatching Chicago's
sewage to the Illinois River and from there, down into
the Mississippi River. The connection between Lake Michigan
and the Illinois River affords the Asian carp an artificial
portal to the Great Lakes.
Herb Gray and Dennis Shornack, co-chairs of the International
Joint Commission, warn that these fish could essentially
wipe out the base of the food chain in the Great Lakes.
The Great Lakes could become one giant carp pond. The
commission is now appealing for government action to ensure
the invasion into our lakes is prevented.
The U.S. Army Corps of Engineers has built an electrical
barrier in the canal to stop Asian carp, but it is not
clear this will be sufficient. Other irritants, such as
noise and bubbles, could be added for maximum effectiveness
in repelling carp. Carp are sensitive to loud noise and
will flee from it, and the bubbles would create a visual
barrier to act as a further deterrent.
The commission has called for a fully funded program
that will keep the existing barrier operating until another
solution is found, and for an additional investment in
backup power to supply the barrier.
The costs of these undertakings, approximately $1-million
(U.S.) for both, are inconsequential compared to the massive,
multibillion-dollar economic damage should an invasion
of these monsters devastate our fishery. The livelihood
of commercial fishers, angling charters, local ports and
spinoff tourism industries such as hotels, restaurants
and retailers would be seriously damaged.
Even if the Asian carp can be prevented entry at the
Chicago canal, the risk is not eliminated. Many people
practise the Asian tradition of releasing one fish for
every one they eat, as a way of increasing personal karma.
Prohibiting the import of Asian carp as food fish could
mitigate this risk. A public education program could help
prevent people from intentionally introducing Asian carp
into our lakes. An aggressive campaign aimed at fishers
to explain why the baitfish they may be dumping into the
lake could be a future nightmare would also be a good
We have learned of the massive and growing insults our
lakes face from alien invasive species. We did not stop
their import even after zebra mussel populations exploded
and showed us all the damage such invaders could perpetrate.
Zebra mussels prefer to form colonies on hard surfaces
where there is flowing water, interfering with the intakes
of water treatment plants, motors of recreational vessels,
and discharge pipes. Costs for treatment and control of
zebra mussels alone in the Great Lakes reach several billion
dollars annually. If Asian carp enter the Great Lakes,
the damage to our ecosystem and our economy could surpass
The Great Lakes continue to acquire a new invader each
year, bringing the total of such imports to a shocking
160 species, most unintentionally introduced by vessels
coming from overseas into the Great Lakes. We need to
manage the ballast water in those vessels, and the sludge
and sediment at the bottom of ballast tanks to end the
invasion from this source.
As for Asian carp, we need to take action immediately.
An ounce of prevention is mandatory because there is no
cure. If we react thoughtfully, but rapidly, we can stop
Asian carp and we can convince individuals that they can
contribute to the solution. The need to act is urgent.
The time to act is now.
Gail Krantzberg is director, Great Lakes Region Office,
of the International Joint Commission.