could threaten Great Lakes
By Matt Whetstone
Published November 29, 2006
CADILLAC - Two electronic barriers separate Lake Michigan
from the Chicago ship canal.
If the barriers are breached, it could prove devastating
to the Great Lakes region. The effort is underway to control
the movement of two species of Asian carp, which are “knocking
on the door,” according to Department of Natural Resources
Fisheries Supervisor Tom Rozich.
The invasive species would pose a significant threat
to the Great Lakes because they are capable of surviving
in cold water, Rozich said. Secondly, they would compete
directly with perch, alewives, smelt and any type of larval
species that subsists on plankton.
“These fish are plankton eaters and they consume huge
amounts of food when they get big,” Rozich said.
The species of carp can grow in excess of 100 pounds.
They pose a unique threat to sportsmen because they are
known to leap out of the water when disturbed by outboard
motors, which can cause injury to people and their boats.
Rozich said the carp have overwhelmed some areas of the
Mississippi River, where they were introduced.
“They can crowd out native species by out-competing for
the plankton forage and by limiting recruitment,” he said.
So far, federal agencies have focused efforts on an electronic
barrier. It has worked to date but one radio-tagged native
carp managed to slip past the barrier.
Rozich has his own theory how the fish entered Lake Michigan.
Because the canal has no current, the fish was likely
stunned. Then, a passing barge caused turbulence, therefore
pushing the carp beyond the threshold of the barrier.
The best bet, Rozich believes, is to undo what man has
already done and fill the ship canal back in.
“My suggestion, to be 100 percent safe, is to fill in
the ship canal and find an alternative means,” Rozich
said. “Biologists really think it would impact the Great
Lake ecosystem and not in a positive manner.”
Michigan Attorney General Mike Cox is urging the feds
to add silver carp and largescale silver carp to a list
of animals that cannot be imported into the country.
“The ecological and economic stakes for Michigan - and
the entire Great Lakes region - are extremely high,” Cox
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Asian carp are voracious eaters and reproduce quickly.
They are known to out-compete native species for small
organisms, which they feed on.
The carp can weigh in excess of 100 pounds and are known
to leap out of the water when disturbed by outboard motors,
causing injury to people and their boats.
Silver carp, one of the invasive species, escaped from
fish farms and sewage treatment basins, entering the Mississippi
and Illinois Rivers and are now threatening to enter Lake