Alien species poised to hit lakes
Invasive critters found in sludge at bottom of ships'
St. Catharines Standard
Neither the absence of sunlight nor the freezing cold
can stop a horde of alien invaders knocking at the door
of the Great Lakes basin.
New research by a University of Windsor student has shown
what many environmentalists have feared for years -- invasive
species are hiding in the slime and sludge found at the
bottom of ballast tanks on ships travelling the Great
Sarah Bandoni, a PhD biology student and researcher at
the university's Great Lakes Institute, said she has discovered
microscopic eggs of tiny water-borne creatures can survive
the harsh conditions of the ballast tanks for long periods.
When the water conditions are right, the eggs hatch.
"It is an evolved defence that allows these organisms'
eggs to survive in these conditions," she said Thursday.
"This means they can be introduced to the Great Lakes."
For years, alien species such as the zebra mussel or
the round-eyed goby have wreaked havoc in the Great Lakes,
pushing out domestic fish by attacking them or significantly
altering their habits.
Most reached the lakes in the ballast tanks of oceangoing
ships that enter the Great Lakes system via the St. Lawrence
In order to protect the lakes from foreign invaders,
ships are now required to dump their ballast before entering
But there is more than water in the ballast tanks. At
the bottom of the tanks is an unpumpable sludge. This
sludge is not regulated and ships carrying it are regarded
as NOBOB (no ballast on board) vessels.
When ships unload or take on cargo in the Great Lakes,
they use lake water as ballast that gets mixed with the
Bandoni's research, part of a joint Canadian/U.S. research
effort, shows there is a potential for a foreign animal
to rise from the sludge and invade the lakes.
Last year, she took samples from lake ships and tested
them in the lab.
She found that the eggs of creatures such as water fleas
will remain dormant until fresh water is added to the
Not even the near-total darkness of the ballast tanks
prevents the eggs from hatching.
"It was thought that light was an important ingredient
to hatching these eggs," Bandoni said. "Well, it isn't."
She suspects when fresh water is added to ballast tanks
while in the lakes, the eggs hatch. When the ballast is
dumped, the critters are free to roam the lakes.
Environmentalists have been calling for regulations to
control the slime on NOBOB ships. However, no regulations
have been passed requiring the removal or treatment of
She is trying to classify the creatures that hatched
in her lab to determine which ones could be a potential
problem for the Great Lakes.
Some of the organisms will be those that are found worldwide,
she said, and others may be domestic to the Great Lakes
basin. Others, however, could be alien in origin.
As well, researchers at two American universities are
testing the ballast slime for bacteria and other organisms
that might find their way into the lakes.
Bandoni will take another series of samples of NOBOB
ballast scum this summer.