Invasive problem wouldn't disappear
with salties' departure
By Peter Passi
Duluth News Tribune
Published December 25, 2005
If ocean-going ships were no longer allowed in the St.
Lawrence Seaway, the problem of invasive species wouldn't
go away. Efforts to control past introductions would continue
to cost millions of dollars.
"But it doesn't help to continue introducing more
stuff," said John Taylor, an associate transportation
professor at Michigan's Grand Valley State University,
who recently published a study of the benefits and costs
of saltwater traffic in the Seaway.
It's difficult to predict how species will interact with
one another, said Anthony Ricciardi, a professor of environmental
science at McGill University in Montreal, Quebec. He explained
that what seems to be a relatively benign introduction
could develop into a major problem, given the right partner.
"The more you add to the mix, the more chance you
could wake up a sleeper cell," Ricciardi said. "The
introduction of one species could cause another to become
The shipping industry recognizes the problem of invasive
species and is searching hard for a solution, said Adolph
Ojard, executive director of the Duluth Seaway Port Authority.
Since 1993, foreign ships have been required to pump
out their tanks and replace any ballast with ocean water
before entering the Seaway. The rationale was that even
if organisms made it through the flushing, few freshwater
species would survive in a high-salt environment.
While this practice has helped, Ricciardi pointed out
that new species continue to arrive in the Great Lakes
Ojard predicts within five years, systems that effectively
kill and remove exotics from ballast water will be ready
for wide-scale deployment.
He points to the Federal Welland, a ship now testing
a system that filters ballast water, pumps nitrogen into
tanks to drive out oxygen and uses cyclone technology
to shred the cells of small organisms that might still
survive in the ballast.
Ballast-free ships are in the works as well. Recently,
the Great Lakes Maritime Research Institute provided funding
to the University of Michigan School of Naval Architecture
to help design a ship with a flow-through ballast system.
"I have no question that the ballast issue will
be solved," Ojard said. "Wouldn't it be a travesty
if that happens, but the Seaway system has been shut down,
never to be resurrected?"