Zebra Mussels spread to Mississippi
above Twin Cities
Posted on October 21, 2005
"I was sent out to clean the minnow bucket and thought,
"Oh great! Another chore!"
Despite that, 14-year-old Gil Millette did what he was
asked last Sunday and in the process discovered a zebra
mussel that had settled on the family minnow bucket which
had been floating in Rice Lake all summer.
The Brainerd boy scout showed it to his dad, Hank, who
took it to the regional DNR office. They sent biologists
out to confirm the spread.
"They found four more on our boat lift and they
found about 30 more on our neighbor's dock lift over there,"
The young man said he recognized the zebra mussel because
he'd paid attention when he was shown several on a fishing
tip to Wisconsin. He figured his discovery turned what
had started as a good day, into a bad one.
Zebra mussels are an invasive species which first turned
up in the U.S. 17 years ago in the Great Lakes.
They breed prolifically and as a result they choke out
native mussels and cause all sorts of damage to water
intake systems on the Great Lakes.
They'd made their way up the Mississippi River to the
Twin Cities, and been spread to two Minnesota inland lakes,
but until this week, the destructive species had not been
found upriver of the Twin Cities.
Five years ago, DNR biologists found them in Lake Zumbro
in Olmstead County. Last year, biologists found them in
Lake Ossawinnamakee in Crow Wing County. Lake Ossawinnamakee
feeds the Mississippi, so it was probable that they would,
sooner or later, be found in northern reaches of the Mississippi.
"In Rice Lake, it's very serious because zebra mussels
could reproduce in Rice Lake... be moved out into the
Mississippi River and be anywhere in the Mississippi River
from Brainerd on down to the Twin Cities," said Gary
Montz, the DNR's zebra mussel coordinator. That's 160
miles of river.
"The zebra mussel is an external spawner. It kicks
the eggs out into the water, and the larval stage, called
the velliger, is microscopic and it floats around for
two or three weeks until it starts developing a shell,
and then it settles to the bottom... During those two
or three weeks, it could be swept miles and miles and
miles from where the parents are," explained Montz.
Two months ago, zebra mussels were discovered in Lake
Mille Lacs, the most popular walleye lake in Minnesota.
Gary Montz says the only way zebra mussels get from lake
to lake is on, or in, boats, much the same way Eurasian
Milfoil is spread. That destructive aquatic plant is now
in control of dozens of lakes across the state.
"You don't know." said Montz, "if you
have a live well or a bait bucket that's full of lake
water, or full of tens or hundreds or thousands of zebra
mussel larvae. Drain that lake water out!"