Invasive species infect 26 more lakes
DNR taking message about pesky mussels, milfoil out
By DON BEHM
Milwaukee Journal Sentinel
June 1, 2002
State boaters carelessly delivered two exotic pests to
26 lakes last year, providing zebra mussels and Eurasian
water milfoil with an opportunity to destroy the water
quality that attracts the public to those lakes in the
first place, a state environmental official said.
The unintended consequence of not properly cleaning boats
and trailers used in previously infested bodies of water
was that zebra mussels were ushered in to eight more lakes
in 2001, while Eurasian water milfoil, a plant, was allowed
to grow its dense mats at 18 additional lakes, said Ron
Martin, coordinator of the aquatic invasive species control
program for the state Department of Natural Resources.
Zebra mussels have a foothold in 32 inland lakes. The
alarming tally of lakes being choked by Eurasian milfoil
stands at 351.
Both aliens depend on humans to help them invade new
places, Martin said.
"They can't fly," he said. "They're at the mercy of humans
to transport them from lake to lake, and there's more
boats out there than ever before.
"The rate at which new lakes are becoming infested leads
me to believe that recreational boaters and anglers are
not getting the message to clean their boats," Martin
said. "We need to remind them of the precautions."
DNR reaching boaters
This year, for the first time, the DNR is carrying that
message directly to where the boaters are.
State employees are at Delavan Lake in Walworth County,
Lake Nagawicka in Waukesha County and several other public
boat launches over the Memorial Day weekend to help boaters
learn how to block the spread of the aliens to even more
lakes and rivers.
Their message simply is to pump water from bilges, drain
water from engines and built-in water storage basins known
as live wells, dump water from bait buckets - but not
the bait - and clean boat hulls and trailers before leaving
launch ramps, Martin said.
"We all need to be aware of invasive species and take
responsibility to prevent them from spreading," Martin
The state will spend $300,000 both this year and next
to educate the public about invading aquatic species,
study the life cycle of these adversaries and devise methods
to slow their spread, Martin said. Of that amount, $50,000
a year will go to boat inspections.
Inspectors will work up to 5,000 hours each year, primarily
at boat launches of already infested lakes and at Lake
"We're hoping this approach can help make a difference
in Wisconsin," Martin said. One reason to change boaters'
habits: Each alien multiplies rapidly once it is introduced
to a new water body.
Female zebra mussels can produce as many as 1 million
eggs per year. Larvae emerging from the eggs float in
the water only a few weeks before they begin developing
shells and settle to the bottom where they attach to any
Floating larvae, known as veligers, can be become trapped
in a bilge pump, live well of a boat or bait bucket where
they are hidden from view, he said.
Eurasian water milfoil, for its part, has the ability
to reproduce from a single segment of stem and leaves.
The segment can take root and form a new colony. Consequently,
fragments of the plant clinging to boats and trailers
can help spread the pest from lake to lake.
New law kicks in
In addition to the money for education and research,
the Legislature gave the DNR another new tool to gain
the public's attention this year.
Beginning this month, it is illegal to launch a boat
or boat trailer in any of the state's navigable waters
if an aquatic plant or a zebra mussel is attached to it.
Violators could pay $50 for a first offense and $100 for
a second offense.
Thirty-two inland lakes now harbor the D-shaped zebra
mussels, which reproduce rapidly in colonies to wreak
havoc on aquatic habitats in various ways, from depleting
oxygen and food that fish depend on, to exacerbating stinky
algal blooms, encrusting piers, damaging boat engines
and clogging water intake pipes.
The mollusk is small, about one inch long, but its striped
shell is sharp and can deter swimmers and strollers when
it accumulates on beaches.
The eight lakes added to the list in 2001 are: Elizabeth
Lake in Kenosha County; Little Cedar in Washington County;
Ellen and Crystal lakes in Sheboygan County; Metonga in
Forest County; Cedar in Manitowoc County; Long in Fond
du Lac County; and Crooked in Waukesha County.
Alien milfoil now thickens the water in a whopping 351
lakes and rivers - hampering swimming, boating and fishing
while crowding out native plants.
The 18 new lakes confirmed to be choking on the plant
in 2001 include the following: Forest, North Twin, South
Twin, Cranberry, Lynx, and Upper Gresham lakes in Vilas
County; Lulu in Shawano County; Mohawksin in Lincoln County;
Kidney in Barron County; Big Elkhart in Sheboygan County;
Bughs and Pine lakes in Waushara County; and Partridge
Crop, Lime Kiln, George, Columbia, Taylor and Stratton
lakes in Waupaca County.
A few of the lakes now burdened with zebra mussels, such
as Long Lake in Fond du Lac County and Lake Metonga in
Forest County, are in previously uninfested watersheds,
Now that the pest has a foothold in those drainage basins,
it easily could be carried into other nearby lakes and
streams and expand infestations across the state unless
boaters pay attention to the stowaways, Martin said.
"The more watersheds that they're in, the faster they
will spread," he said.
Zebra mussels came from Europe and were first discovered
in Lake Erie and Lake St. Clair near Detroit in 1988.
They arrived there in 1985 or 1986 in the ballast water
of ocean freighters.
Since then, boaters have moved the mollusks into all
the Great Lakes and Green Bay and into the Mississippi,
St. Croix and Ohio rivers.
Eurasian water milfoil is native to Europe, Asia and
northern Africa and was found growing in U.S. lakes in
the 1940s. It first showed its dense mats in several Wisconsin
lakes in the 1960s, and this alien species is now found
in all but 17 counties in the state.