Non-native species are damaging
our Great Lakes ecosystem
By Tim Martin
Lansing State Journal
Fifteen years after it was detected in the Great Lakes
region, the zebra mussel continues to spread - causing
at least $10 million in annual damage by clogging everything
from boat motors to intake pipes at nuclear power plants.
Another European invader, the pretty-but-potent purple
loosestrife plant, infests acres of waterways in a single
stretch, choking out vegetation that serves as food and
protection for wildlife.
They are among the more than 170 fish, plants and other
foreign aquatic life forms that came here from overseas,
mostly in the hulls of ships, and continue to cause problems
in the region's waterways.
New invaders are discovered in the Great Lakes every
year. And the worst of the bunch may be just 25 miles
southwest of Lake Michigan in the Illinois River.
The Asian carp, which grows up to 4 feet long and can
weigh 100 pounds, could decimate the Great Lakes' $4 billion-a-year
fishing business by crowding out native fish and eating
their food, researchers say.
"The Asian carp is the poster child for invasive
species. It could turn the Great Lakes into a carp pond,''
said Dennis Schornack, U.S. chair of the International
Joint Commission, a U.S.-Canadian panel that helps find
solutions to problems in the Great Lakes.
Schornack and others say more needs to be done to battle
invasive species. Other troublesome invaders include the
Eurasian round goby, which eats the eggs of native fish,
and spiny waterfleas, which clog up fishing gear.
Invasive species are a particularly important issue in
Michigan, which is home to more than 3,000 miles of Great
Lakes shoreline vital to recreation, tourism and economic
"We've got to get everybody moving in the right
direction on addressing the invasive species issue ...
it ought to be moving more quickly," Schornack said.
"We can't afford to wait.''
The Asian carp may be threatening enough to focus state,
federal and international attention on an issue that many
critics say never has received enough.
The number of unintended, invasive imports has skyrocketed
since 1959, when the St. Lawrence Seaway opened to connect
the Great Lakes to the Atlantic Ocean. Guarding against
invasive species will require more money and a clearer
focus, according to a late 2002 report from the General
Accounting Office, the investigative branch of Congress.
Current regulations may have slowed the spread of invasive
species, but it hasn't kept them out of the Great Lakes.
Critics say the regulations on ship ballast water are
ineffective, and more money is needed to address the overall
The federal government and state of Illinois are attempting
to rally with a $7 million electric barrier under construction
in the Chicago Ship and Sanitary Canal, which connects
Lake Michigan with the Mississippi River system. The barrier,
which should be finished in 2004, would augment a temporary
barrier installed last year, sending small shocks designed
to drive back the fish.
The Asian carp was intentionally imported to the United
States in the 1970s. Arkansas catfish farmers used the
carp to clean up algae and waste in their production ponds.
But the fish escaped into the Mississippi River a decade
ago, when flooding overwhelmed fish ponds. The carp has
moved upstream 40 to 50 miles a year and now is in the
upper Illinois River. From there, the Chicago Ship and
Sanitary Canal connects the Mississippi system to the
There was a report of a bighead carp found in Lake Erie
last year, but researchers say there's no evidence the
species remains there.
Asian carp can eat half their weight in plankton and
other small organisms each day. A single female can produce
as many as a million eggs.
It wouldn't take long for the carp to become the dominant
Great Lakes species. That's a disturbing thought, experts
say, because the carp has virtually no commercial value
compared with the whitefish, trout, bass, walleye and
other species now prevalent in the region's waters.
Another hazard: the "silver" type of Asian
carp can leap eight feet out of the water when startled
by a boat motor or sudden waves. An Illinois man, smacked
in the face by a silver carp, suffered a broken nose.
A Missouri biologist lost a filling from a tooth.
"Just about everybody on my staff has been hit by
one at some point or another,'' said Greg Conover, a U.S.
Fish and Wildlife Service biologist in Illinois.
Conover took a hit on the chest during a recent boat
trip on the Illinois River. "If it would have hit
my shoulder, it probably would have been dislocated,''
Preventive measures are sought for invasive species because
once they're here, they're difficult to control. The prime
example is the fingernail-size zebra mussel, which has
spread rapidly since it was first detected in the United
States in Lake St. Clair in 1988.
The mussel since has spread to all five Great Lakes,
about 150 inland Michigan lakes and 20 other states. The
U.S. power industry spends up to $60 million a year maintaining
pipes clogged with the invaders. The total cost to industry,
business and recreation in the next 10 years could approach
"We have them on our docks. We have them on our
boats,'' said Cindy Wycoff, who lives on Lake Lansing
in Meridian Township. "I've stepped on clams with
zebra mussels attached to them and cut my foot.''
Zebra mussels can stick to just about any solid surface
- that's how they move from lake to lake, tagging along
on boats, trailers or inside motors.
In the late 1980s, zebra mussels infested a City of Monroe
water facility on Lake Erie. About 24,000 residents faced
service interruptions while the meddling mussel was turned
back - at a cost of $300,000.
While the mussel filters and clears lakes of some types
of algae, it also works in reverse. Blooms of blue-green
algae have been reported in some areas of high infestation,
including Lake Huron's Saginaw Bay. Last week, a research
team headed to the middle of Lake Erie to determine if
the zebra mussel was contributing to a low-oxygen, high-phosphorous
"dead zone'' there.
Mussels have clogged water intake valves and pumps at
power plants along Lake Michigan. The cleanup cost has
inflated utility bills for residents in several states.
The tiny troublemakers may also mess up the food chain.
Since the zebra mussel arrived in the Great Lakes, levels
of diporeia - tiny crustaceans favored as food by whitefish,
smelt and other native species - have declined. Researchers
haven't nailed down the exact cause-and-effect of the
disappearance, but it coincides with the emergence of
the zebra mussel and its more recently emerging relative,
the quagga mussel.
Fisheries in northern Lake Michigan say the whitefish
are skinnier than they used to be - sometimes too thin
to salvage a usable fillet.
Researchers are studying ways to poison the mussels without
harming other aquatic life, but after 15 years, the mussels
appear entrenched. And, like most invasive species, the
long-term consequences of their appearance aren't yet
"Any time an aquatic invasive species emerges, it's
like an unplanned, uncontrolled experiment,'' said David
Reid, a scientist with the National Oceanic and Atmospheric
Administration's Great Lakes Environmental Research Laboratory
in Ann Arbor.
"It's anybody's guess exactly where it will go.''