[USA] Clad in a wet suit and submerged to his chin, Jon Bunn sweeps a six-inch vacuum hose across the lake bottom, sucking up aquatic weeds and some sediment in an attempt to halt the spread of the invasive starry stonewort algae from Little Muskego Lake’s Hillview Bay.
Sucked through a grinding pump, the weed and sediment slurry is pumped to a manifold atop three 20-yard dumpsters lined with massive water filtration bags that retains the slurry and drains the filtered water back to the bay.
“If the dewatering bags work quick, we can clear 5,000 to 8,000 square-feet in a day,” said Gregg Jablonowski, general manager for field operations for Eco Waterway Services of East Troy.
The Little Muskego Lake District and the Department of Natural Resources are battling the spread of the highly invasive weed from Hillview Bay to other parts of the lake and onto other lakes in the state.
Since its discovery in Little Muskego Lake last fall, the DNR and its partners have confirmed the algae’s presence in Big Muskego Lake and adjoining Bass Bay, Long Lake in Racine County and Silver and Pike lakes in Washington County.
Little Muskego Lake was the first lake in Wisconsin where the invader was found. Those living around the lake were extremely worried about this new threat. Initially, criticism was leveled at the DNR for not moving as fast as lake-dwellers wanted.
More recently, the Little Muskego Lake District asked to close all boat launches except the busy Idle Isle launch because starry stonewort is spread almost exclusively aboard boats. With a state grant, the lake district arranged to have a boat inspector at Idle Isle some of the time.
Early fear that the new invader was a lake killer reached as far as residents of Eagle Lake located between Union Grove and Burlington. The Eagle Lake District called on the DNR to close all launches on Little Muskego Lake and to start chemical treatments immediately. Also, the nearby Wind Lake association called for a halt to all boating on Little Muskego Lake.
While the discovery of starry stonewort in a bay of Little Muskego Lake rocked lake dwellers, in July the algae was found all over Big Muskego Lake and in Bass Bay. Discoveries of starry stonewort in the other two lakes followed.
As a result of starry stonewort being in Big Muskego Lake, the lake district is contemplating hiring a biochemist to do a plant study.
In the meantime, Little Muskego Lake is deep into its battle with starry stonewort not only using DASH but by having divers hand pull the plants in lightly infested areas. So far, the district has not used chemicals, mainly because they leave the plant’s star-shaped bulbils in the lake bed unaffected to grow another plant.
Diver-Assisted Suction Harvest (DASH) removes the algae, its roots and the bulbils that help the invasive plant reproduce, Jablonowski said.
Having vacuumed a dense area off the Hillview Drive boat launch in July, Jablonowski and his crew returned in September to clear the the shoreline of an island jutting from the end of Gold Drive.
“We’re trying to stop the starry stonewort from creeping around the island point and into the next bay.” Jablonowski explained.
From there, the Eco Waterway Services team will shift to two hotspots in the vicinity of Kingston and Moonlight bays.
Including two $20,000 DNR Rapid Response grants, the district has spent nearly $60,000 to inspect and inventory the lake, for the DASH project, and for communications to lake residents and lake users, said District President Tom Reck.
Photo: Gregg Jablonowski connects a suction hose to a grinding pump on Sept. 2 used by Eco Waterway Services to vacuum Starry Stonewort algae from Little Muskego Lakeâs Hillview Bay. – Image credit: C.T. Kruger.
View original article at: Lakebed vacuuming latest tactic against invasive starry stonewort algae