| New Biological Pollution to Region still possible
More exotics coming say researchers
Biological Pollution and ”nonindigenous exotic species” will keep invading the Great Lakes for
the foreseeable future. And they will pose new risks to our ecosystem, already altered by
foreign invaders like the zebra mussel and spiny water flea.
That's the conclusion of a new study published in the Canadian Journal of Fisheries and
Aquatic Sciences. It predicts 17 species of foreign clams, fish, shrimp and invertebrates likely
will be transported to the Great Lakes from the Caspian Sea, which borders eastern Europe
and Asia.
"Our results suggest that the Great Lakes-St. Lawrence system and other North American
waterways will continue to receive and be impacted by invasive Eurasian fauna", wrote
scientists Anthony Ricciardi and Joseph Rasmussen. The arrival of additional exotic species
could be prevented, they suggest, if more money were spent on identifying potential new
invaders and taking steps to keep them from entering the Great Lakes. Such control measures
might have kept zebra mussels from invading the Great Lakes and spreading to other inland
lakes and rivers across much of the eastern U.S., Ricciardi and Rasmussen said.
In 1980, scientists hired by the Canadian government reported finding zebra mussel larvae in
the ballast water of European freighters entering the Great Lakes, according to the study.
Although those scientists predicted zebra mussels would colonize North American waters,
nothing was done to attack the zebra mussel problem until these critters began clogging water
intakes in the late 1980s.
"Many of these invasions are preventable," said Gary Fahnenstiel, director of the feds' Lake
Michigan Field Station in Muskegon. Tougher rules governing the discharge of ballast water
from freighters into the Great Lakes have failed to stop the flow of exotic species into the
lakes, Fahnenstiel said. "We are moving very, very slowly on ballast water control when we
know the risks to the Great Lakes are very large," Fahnenstiel said. "It's time to really get
serious about ballast water controls; we need to move quickly and do something."
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Existing federal laws governing ballast water discharges contain loopholes that allow most
transcontinental freighters to enter the Great Lakes carrying ballast water from European and
Asian ports. That ballast water and sludge, ”some of which is still discharged in Great Lakes
waters,” often contains exotic species that can cause ecological chaos, state and federal
officials said.
The zebra mussel has essentially altered the Great Lakes ecosystem since its arrival a decade
ago, according to Tom Nalepa, a biologist at the Great Lakes Environmental Research
Laboratory in Ann Arbor. "In the nearshore areas of the Great Lakes, there hasn't been a
component of the biological food web that hasn't been affected by zebra mussels," Nalepa
said. "From bacteria to fish, everything has been affected."
Zebra mussels also are suspected of causing the disappearance of some types of Great Lakes
fish food. Scientists said other exotic species, ”including the spiny water flea, ruffe and
goby” threaten a billion-dollar Great Lakes sport fishery. A cousin of the spiny water flea,
called cercopagis, was discovered last summer in Lake Ontario.
Ricciardi and Rasmussen predicted 12 new species of exotic shrimp and other invertebrates,
three species of fish, one type of worm and another foreign clam are likely to invade the Great
Lakes from the Caspian Sea region. One type of exotic fish, called the tyulka, would threaten
yellow perch and other Great Lakes fish, according to the study's authors. Animals from the
Caspian Sea are most likely to invade the Great Lakes because many of the species there are
capable of surviving in freshwater or saltwater, and freighters from that region often travel to
North America, scientists said.
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