DNR confirms finding zebra mussels
in Upper Mississippi River near Brainerd
By T.W. Budig
ECM capitol reporter
Posted on hometownsource.org on October 24, 2005
A dockside discovery in Brainerd shows an aggressive
invasive species for the first time infests the Upper
A Brainerd boy recently noticed a small zebra mussel
attached to a bait bucket dangling from the family dock
in Rice Lake, an impoundment of the Mississippi River.
Local Department of Natural Resources (DNR) officials
later confirmed the mussel was indeed a zebra. And a subsequent
search of the lake bottom around the dock found other
According to Gary Montz, zebra mussel coordinator for
the DNR, this is the first time the zebra mussel has been
discovered on the Upper Mississippi.
Although zebra mussels infest the lower river, it was
previously believed they had no extended further north
than St. Anthony Falls in Minneapolis.
“It is likely that zebra mussels have become established
in other areas of the (upper) river or adjacent backwaters
that we haven't discovered yet,” said Montz.
There is no known way of chemically treating for zebra
mussels that won’t kill other aquatic life.
Beyond this, chemically treating a river is virtually
impossible, Montz explained.
Zebra mussels, a “D”-shaped mussel native to the Caspian
Sea and first discovered near Detroit in 1988, currently
infests the Great Lakes, the Mississippi River, and the
St. Croix River north of Stillwater down.
Generally under an inch in length, yellowish or brownish
in color and striped, zebra mussels attach themselves
to metal, rubber, many other natural and man-made surfaces.
Native mussels fall victim to the invader.
Once attached to native mussels, zebra mussels through
sheer numbers can suffocate them or prevent them from
feeding, Montz explained.
Zebra mussels clog pipes, and are often discovered by
swimmers or waders who cut themselves on the sharp shells.
Some fish species such as drum do eat zebra mussels,
as well as diving ducks, but a female zebra mussel can
produce as many as a million eggs a year.
Predation will not hold numbers in check, Montz explained.
“Zebra mussels are not mobile on their own,” said Montz.
Often the mussel is moved from one spot to another aided
by humans — carried as larva in fish live wells, for instance.
The DNR advises boaters and anglers:
•Remove all aquatic plants from boat and trailer when
leaving the water.
•Drain all lake water from live wells or bilges before
leaving the access site.
•Wash watercrafts in hot water and let them dry for five
days before taking them into a different body of water.
•Use the same precautions for other aquatic gear.
Montz does not consider the further infestation of the
zebra mussel inevitable.
While species do replace other species over time, the
movement of the zebra mussel across the globe has been
unnatural and its dangerous to throw a foreign invader
into a new habitat.