Above: a Diver-Assisted Suction-Harvesting demonstration. Divers pull vegetation from the lake bottom and feed the material through a vacuum tube. The material comes up to the modified pontoon platform, is filtered, and bagged for removal on land.
At Steamboat Bay - The starry stonewort issue
About Starry Stonewort in Leech Lake
Starry Stonewort was discovered in Steamboat Bay of Leech Lake in the late summer of 2021. An area of about 6 acres was determined to be infested along and in the wild rice bed in northwestern Steamboat Bay and in Anderson’s Cove Harbor on the west side of the bay. Starry Stonewort threatens the recreational potential and fisheries of our lakes. Its thick matted growth can extend from the bottom up to the surface in water as deep as 7 feet. In shallow water it can restrict water movement causing stagnant conditions leading to surface scum and seriously impacting recreation. In water down to 20 feet Starry Stonewort often covers the lake bottom with thick pillows that exclude other plant species, interfere with fish spawning and disrupt fish foraging behavior. Starry Stonewort is known to deplete oxygen levels, killing the small critters on the lake bottom, making the sediment inhospitable to other plant growth, and releasing nutrients from the sediments. This “pickling” becomes so severe the Stary Stonewort ends up killing even itself. After pickling no plants will grow in the area for several weeks or months until Starry Stonewort re-establishes.
Working to Keep Starry Contained - A Short History
Currently Starry Stonewort is contained to the northwest corner of Steamboat Bay and the Leech Lake Association is working in partnership with the Leech Lake Band of Ojibwe (LLBO), Cass County AIS Program, Anderson's Cove Resort, Minnesota Island Community, and Minnesota DNR in attempts to keep it cornered there. In 2021 the Leech Lake Band of Ojibwe contracted a company from Wisconsin to perform Diver Assisted Suction Harvesting (DASH) to remove Starry stonewort and its reproductive star shaped structures called bulbils from inside and just outside Anderson’s Cove Harbor. The Cass County AIS staff assisted in implementing the project. The project treated several acres and removed a significant amount of the Stonewort but left many reproductive bulbils in the lake bottom. In 2022 The Minnesota DNR funded removal by hand pulling it in Anderson's Cove to limit the potential for its spread around Leech Lake and around 20,000 lbs were removed. The Leech Lake Band of Ojibwe performed DASH removal of Starry stonewort with their newly purchased unit and coordinated hand pulling efforts in Steamboat Bay.
In 2023 DASH was used to knock back the Starry Stonewort in Anderson's Cove to limit the potential spread around Leech Lake. These efforts were funded by the Leech Lake Association, the Cass County AIS program, a MN DNR grant, and donations from Anderson's Cove Harbor and Minnesota Island residents. The Leech Lake Band of Ojibwe continued their research into Starry stonewort’s impacts on native plant growth, primarily wild rice, in Steamboat Bay. The Leech Lake Band of Ojibwe also surveyed 100 sites spread across Leech Lake as part of their partnership with MN DNR in an LCCMR-funded native stonewort and chara study; no Starry stonewort was found at any of the sites surveyed. The Leech Lake Association and the Cass County AIS program surveyed resort accesses and harbors around Leech Lake and identified smaller patches of SSW in the Hiawatha Beach Harbor.
In 2024
For 2024 the Leech Lake Association and Cass County AIS program in consultation with MN DNR and the Leech Lake Band of Ojibwe conducted additional DASH or hand-removal work in Anderson's Cove to limit the potential spread of Starry stonewort to new sites in Leech Lake or elsewhere through transient boat traffic. The Cass County AIS program also obtained quotes for SCUBA hand pulling in Hiawatha Beach Harbor. Most recent SSW removal efforts in the harbor have involved state, county, and private sources providing $26,946 for Aquatic Plant Management, Inc. to perform DASH removal in 2023 and 2024. Cass Soil and Water Conservation District has been the largest donor through its Aquatic Invasive Species Partnership program, but local citizens groups, owners Ann and Chris Anderson, the Leech Lake Association and others have also contributed generously to this work. Approximately 230 cubic feet or 5,000 pounds of SSW were removed from the harbor in each of the last two years.
In 2025
A collaborative research effort has been established between LLBO and the Minnesota Aquatic Species Research Center (MAISRC) to determine the rate of spread and effects of SSW on the culturally cherished wild rice beds and other native aquatic plants in Steamboat Bay.
Preliminary results from the two years of the LLBO-MAISRC study show three things: 1. Starry stonewort is not spreading spatially beyond where it is has been found. 2. SWW is increasing in biomass where it has been documented. 3. There’s no notable data saying wild rice is directly impacted by SSW’s presence. The cyclical nature of wild rice’s ‘boom and bust’ years, combined with just two growing seasons of data, may result in an uncertain outcome of how wild rice is affected long term. LLBO Invasive Species Specialist Raining White is excited about employing a recently purchased drone equipped with hyper-spectral imaging to track SSW-wild rice dynamics from shore. An underwater drone is utilized during winter months to observe SSW and other aquatic plants through the ice.
New Techniques to be Explored
To improve our ability to control Starry Stonewort, the Cass County AIS program is applying for grant funding from the Minnesota Aquatic Invasive Species Research Center to test new or developing control techniques. Ideas include using UVC light to kill the Starry Stonewort, using hot water treatments within a shielded area to collapse the excessive growth, and using biodegradable burlap barriers on the lake bottom to prevent regrowth and allow native plants to regenerate. These concepts have been used for similar species in other states but have not been employed or studied in Minnesota or for use on Starry stonewort. The Cass County AIS program is also planning to implement aquatic plant surveys in Steamboat Bay to document any spread of Starry Stonewort across the bay and ensure our planned control methods are appropriate for the current invasion status or limited occurrence in the lake.
If you want to learn more about starry stonewort in Leech Lake, please contact John Eaton, Leech Lake Association director, at [email protected], or Steve Henry, Cass AIS Technician, at [email protected]
Starry Stonewort was discovered in Steamboat Bay of Leech Lake in the late summer of 2021. An area of about 6 acres was determined to be infested along and in the wild rice bed in northwestern Steamboat Bay and in Anderson’s Cove Harbor on the west side of the bay. Starry Stonewort threatens the recreational potential and fisheries of our lakes. Its thick matted growth can extend from the bottom up to the surface in water as deep as 7 feet. In shallow water it can restrict water movement causing stagnant conditions leading to surface scum and seriously impacting recreation. In water down to 20 feet Starry Stonewort often covers the lake bottom with thick pillows that exclude other plant species, interfere with fish spawning and disrupt fish foraging behavior. Starry Stonewort is known to deplete oxygen levels, killing the small critters on the lake bottom, making the sediment inhospitable to other plant growth, and releasing nutrients from the sediments. This “pickling” becomes so severe the Stary Stonewort ends up killing even itself. After pickling no plants will grow in the area for several weeks or months until Starry Stonewort re-establishes.
Working to Keep Starry Contained - A Short History
Currently Starry Stonewort is contained to the northwest corner of Steamboat Bay and the Leech Lake Association is working in partnership with the Leech Lake Band of Ojibwe (LLBO), Cass County AIS Program, Anderson's Cove Resort, Minnesota Island Community, and Minnesota DNR in attempts to keep it cornered there. In 2021 the Leech Lake Band of Ojibwe contracted a company from Wisconsin to perform Diver Assisted Suction Harvesting (DASH) to remove Starry stonewort and its reproductive star shaped structures called bulbils from inside and just outside Anderson’s Cove Harbor. The Cass County AIS staff assisted in implementing the project. The project treated several acres and removed a significant amount of the Stonewort but left many reproductive bulbils in the lake bottom. In 2022 The Minnesota DNR funded removal by hand pulling it in Anderson's Cove to limit the potential for its spread around Leech Lake and around 20,000 lbs were removed. The Leech Lake Band of Ojibwe performed DASH removal of Starry stonewort with their newly purchased unit and coordinated hand pulling efforts in Steamboat Bay.
In 2023 DASH was used to knock back the Starry Stonewort in Anderson's Cove to limit the potential spread around Leech Lake. These efforts were funded by the Leech Lake Association, the Cass County AIS program, a MN DNR grant, and donations from Anderson's Cove Harbor and Minnesota Island residents. The Leech Lake Band of Ojibwe continued their research into Starry stonewort’s impacts on native plant growth, primarily wild rice, in Steamboat Bay. The Leech Lake Band of Ojibwe also surveyed 100 sites spread across Leech Lake as part of their partnership with MN DNR in an LCCMR-funded native stonewort and chara study; no Starry stonewort was found at any of the sites surveyed. The Leech Lake Association and the Cass County AIS program surveyed resort accesses and harbors around Leech Lake and identified smaller patches of SSW in the Hiawatha Beach Harbor.
In 2024
For 2024 the Leech Lake Association and Cass County AIS program in consultation with MN DNR and the Leech Lake Band of Ojibwe conducted additional DASH or hand-removal work in Anderson's Cove to limit the potential spread of Starry stonewort to new sites in Leech Lake or elsewhere through transient boat traffic. The Cass County AIS program also obtained quotes for SCUBA hand pulling in Hiawatha Beach Harbor. Most recent SSW removal efforts in the harbor have involved state, county, and private sources providing $26,946 for Aquatic Plant Management, Inc. to perform DASH removal in 2023 and 2024. Cass Soil and Water Conservation District has been the largest donor through its Aquatic Invasive Species Partnership program, but local citizens groups, owners Ann and Chris Anderson, the Leech Lake Association and others have also contributed generously to this work. Approximately 230 cubic feet or 5,000 pounds of SSW were removed from the harbor in each of the last two years.
In 2025
A collaborative research effort has been established between LLBO and the Minnesota Aquatic Species Research Center (MAISRC) to determine the rate of spread and effects of SSW on the culturally cherished wild rice beds and other native aquatic plants in Steamboat Bay.
Preliminary results from the two years of the LLBO-MAISRC study show three things: 1. Starry stonewort is not spreading spatially beyond where it is has been found. 2. SWW is increasing in biomass where it has been documented. 3. There’s no notable data saying wild rice is directly impacted by SSW’s presence. The cyclical nature of wild rice’s ‘boom and bust’ years, combined with just two growing seasons of data, may result in an uncertain outcome of how wild rice is affected long term. LLBO Invasive Species Specialist Raining White is excited about employing a recently purchased drone equipped with hyper-spectral imaging to track SSW-wild rice dynamics from shore. An underwater drone is utilized during winter months to observe SSW and other aquatic plants through the ice.
New Techniques to be Explored
To improve our ability to control Starry Stonewort, the Cass County AIS program is applying for grant funding from the Minnesota Aquatic Invasive Species Research Center to test new or developing control techniques. Ideas include using UVC light to kill the Starry Stonewort, using hot water treatments within a shielded area to collapse the excessive growth, and using biodegradable burlap barriers on the lake bottom to prevent regrowth and allow native plants to regenerate. These concepts have been used for similar species in other states but have not been employed or studied in Minnesota or for use on Starry stonewort. The Cass County AIS program is also planning to implement aquatic plant surveys in Steamboat Bay to document any spread of Starry Stonewort across the bay and ensure our planned control methods are appropriate for the current invasion status or limited occurrence in the lake.
If you want to learn more about starry stonewort in Leech Lake, please contact John Eaton, Leech Lake Association director, at [email protected], or Steve Henry, Cass AIS Technician, at [email protected]