GLENWOOD, Minn.—When announcing the discovery of starry stonewort in Lake Minnewaska last week, the Minnesota Department of Natural Resources said the invasive algae has never been eradicated from any U.S. lake where it has been found.
Minnewaska Lake Association President Mike Stai believes the case on Minnewaska might be able to change that.
So far, the infected area on Minnewaska has been limited to the 1.5-acre area within the marina in Starbuck. Stai wrote in a press release that the DNR's survey of the lake outside the marina and on both the north and south shores did not show any of the algae present.
Starry stonewort can form dense mats that can interfere with fish spawning habitat, recreational use of the lake and compete with native plants.
"Fortunately, we found it soon enough so we can actually do something about it before it gets into the main lake," Stai said in an interview.
The lake association immediately agreed to an aggressive action plan. The DNR said in its release that starry stonewort hadn't been eradicated, but that treatment can help ease its effects on the body of water. Stai is confident that having the algae confined only to the marina ups the odds of actually killing starry stonewort on Minnewaska.
"In most cases, it's in the main lake so they don't have a controlled area where they can actually treat the entire area where it's infested," Stai said. "This isn't outside the marina. They have docks on both sides and then a channel down the middle where you can barely meet a boat. We're going to treat the whole thing. We have the advantage of it being contained, and that's why we want to treat it right away."
Stai reached out to the president of the lake association on Lake Sylvia, a body of water in Wright County where the DNR found starry stonewort present in 2016.
"We're working with the company Lakes Restoration out of Rogers that treats our milfoil," Stai said. "They are the ones that treated on Koronis and Lake Sylvia, and they've had great results killing it. The key is keeping it contained like it is."
On Aug. 24, the Minnewaska Lake Association board met with leaders from the city of Starbuck, along with DNR Glenwood Area Fisheries Manager Dean Beck to discuss a plan to combat the algae. Stai said the city of Starbuck authorized the chemical treatment of the 1.5-acre marina using chelated copper algaecide and immediately closed the two public boat landings in the marina to minimize boat traffic. The plan was to reopen the boat landings for the Labor Day weekend.
Stai said the lake association board approved a motion to cover the $1,653 cost for the initial chemical treatment in order to apply it as soon as possible. As of Monday morning, Stai said they were still waiting for the DNR to complete the permit but that the first of what will likely be multiple applications of the chemical were to happen on Monday or Tuesday of this week.
"We want to do it immediately," Stai said. "That's why the lake association board voted Thursday night that we'll fund the first treatment, and then we're going to work with the DNR and the county, try to get some donations and stuff to try to manage it if we have to treat it again this year and next year, so hopefully we can fund it that way."
Stai said that the lake association, city of Starbuck and the DNR will meet in the near future to develop an ongoing plan to monitor and to continue to treat the infestation.
"The key is just keep hitting this stuff hard," Stai said. "If you have a contained area, we should be able to kill it. One treatment isn't going to do it, though. That's the challenge."
Stai got the phone call on Aug. 21 from Mark Ranweiler of the Minnesota DNR giving him the news that Minnewaska had become the 11th lake in Minnesota where the DNR confirmed the existence of starry stonewort.
It is the second confirmed infestation in a Minnesota lake in 2017.
"Frustration more than anything," Stai said of his reaction to the discovery. "We know there's boats coming from all over into Minnewaska and people just don't do their due diligence and keep the weeds off before they drop it into another lake."
Starry stonewort is most likely spread when fragments have not been properly cleaned from trailered boats, personal watercraft, docks, boat lifts, anchors or other water-related equipment, the DNR said.
This new confirmation reminds boaters and anglers to follow Minnesota laws to prevent the spread of aquatic invasive species:
• Clean aquatic plants and animals from watercraft.
• Drain all water by removing drain plugs and keep drain plugs out while transporting watercraft.
• Dispose of unwanted bait in the trash.
Some invasive species are small and difficult to see at the access. To remove or kill them, take one or more of the following precautions before moving to another waterbody, especially after leaving infested waters:
• Spray with high-pressure water.
• Rinse with very hot water (120 degrees Fahrenheit for at least two minutes or 140 degrees Fahrenheit for at least 10 seconds).
• Dry for at least five days.
Details about starry stonewort and other aquatic invasive species are available at mndnr.gov/ais.