Great Lakes are fighting for their
By Tom Meersman
Minneapolis-St. Paul Star Tribune
Published June 29, 2004
- The Great Lakes have become a giant outdoor biology
experiment - with no one in charge.
In the space of a few decades, an evolutionary snap of
the fingers, vast populations of foreign fish, mussels
and other creatures have invaded and damaged irreversibly
an ecological design that took thousands of years to evolve.
These unwanted guests in the largest freshwater system
on Earth have muscled out native species, killed thousands
of loons and other migrating birds, devoured food resources,
clogged water-intake pipes and begun to spill into many
of North America's premier interior lakes and rivers.
Many scientists say the invaders are a worse problem
than the industrial contamination that fouled the Great
Lakes in the 1960s.
They can't be mopped up like a spill or turned off like
a faucet. Some scientists think of the invaders as biological
pollution: They adapt, reproduce and spread. No one species
of invader has been eradicated. Many have no native predators
to keep them in check.
Unlike industrial pollution, much of the new damage is
nearly invisible, hidden in the lakes' murky depths. Yet
biologists who study lakes say the evidence is mounting
that the unintended introductions of species from around
the world could soon dominate the lakes' ecology.
The onslaught also affects Chesapeake Bay, San Francisco
Bay and other North American marine systems, but the Great
Lakes are special because of their immense stores of fresh
water. Some changes could pose a threat to humans, and
health experts have issued warnings about the risks. Botulism
and bacteria that cause cholera are documented consequences
of the invasion. So far, no humans have been reported
At stake is a resource that millions of Americans and
Canadians rely on for drinking water, recreation and their
economic livelihood. Many experts say the governments
of the United States and Canada have not done enough to
stop potential new invaders.
One paradox is that the lakes' improved water quality
of the past three decades, especially in harbors, may
help the foreign creatures flourish.
The invasion of alien plants and animals - 179 of them
by the latest count - began in the early 1800s, and it
picked up steam after the St. Lawrence Seaway opened the
lakes to oceangoing ships in 1959. More than 40 percent
of the Great Lakes' invaders have been discovered since
then and most arrived by ship from Europe or Asia, according
to research data analyzed by the Minneapolis Star Tribune.
A new invader is identified in the lakes about every
"They're coming in faster than we can study them,"
said Anthony Ricciardi, invasive species biologist at
McGill University in Montreal.
Another scientist who has studied the Great Lakes basin
for 50 years now describes it as "a sick system."
Henry Regier, a professor emeritus of zoology and environmental
studies at the University of Toronto, said he has never
seen such dramatic changes in the lakes.
The alien species have created an "accidental zoo,"
said James Carlton, director of the Maritime Studies Program
of Williams College in Mystic, Conn. The lakes, he said,
have been permanently modified "on one of the greatest
scales in any aquatic environment in the world."
Nature changes on its own over time. Aquatic populations
fluctuate, and some creatures migrate to new areas or
go extinct. And not every introduced fish, worm or plant
disrupts the environment.
Some people question the severity of the problem, but
even the shipping industry concedes that it has transplanted
unwanted creatures around the globe.
Scientists rarely make guarantees, but their observations
about the current state of the lakes are consistent in
dozens of studies: The doors for invaders to enter North
American waterways are wide open, and the Great Lakes
are fighting for their lives.
While experts have been raising red flags about the invaders
for decades, they have received little public or government
attention. Almost all federal funds provided to counter
foreign species are devoted to terrestrial pests that
threaten agricultural crops and forests, not to aquatic
For two years Congress has been studying whether to strengthen
laws about invasive species. Two House subcommittees held
a joint hearing in March, but it is unclear whether legislation
will be passed.
U.S. officials also have considered establishing a national
screening system to prohibit imports of creatures with
a high potential to spread uncontrollably in the wild.
Such a system already exists to exclude foreign plants
that could endanger agricultural crops, but the worldwide
trade in fish, aquatic plants and other potential invaders
remains largely unregulated.
"We're completely in a reactive mode in dealing
with these invasive species, in both the United States
and Canada," said Hugh MacIsaac, invasion biology
research chair at the University of Windsor and one of
Canada's leading researchers on the issue.
In the meantime, invaders continue to be discovered,
and no one knows how much havoc the next one may wreak.
"Every time we have a new species that enters the
Great Lakes, we're instigating yet another unplanned and
uncontrolled biological experiment on our ecosystem,"
said David Reid, a research scientist at National Oceanic
and Atmospheric Administration's Great Lakes Environmental
Research Laboratory in Ann Arbor, Mich. "We are playing
ecological roulette with the Great Lakes."