Starry stonewort infestation confirmed in Turtle Lake near Bemidji

Note: The following press release has been reposted from the Minnesota Department of Natural Resources.

Minnesota’s second known infestation of starry stonewort (Nitellopsis obtusa), an invasive form of macro algae, has been confirmed by the Minnesota Department of Natural Resources. The infestation is in Turtle Lake near Bemidji. 

Turtle Lake is 185 miles due north of Lake Koronis and Mud Lake, connected to Koronis, in Stearns and Meeker counties, where the state’s first starry stonewort infestation was confirmed by the DNR in August last year. The DNR has conducted numerous surveys of lakes in a wide radius of Lake Koronis and around the state and had not found any other infestations. 

“The infestation was reported in Turtle Lake by an individual who first noticed a heavy growth of underwater vegetation last summer,” said Ann Pierce, section manager for the DNR's Ecological and Water Resources Division. “At that time, they thought it was a native algae called chara (pronounced CARE-uh), showing none of the characteristic bulbils that develop in mature starry stonewort. This year when the individual who reported it looked again, he saw those telltale bulbils.

“We strongly encourage anyone who is uncertain of the identity of a species and suspects it may be starry stonewort or any other aquatic invasive species to contact the DNR so we can check it out.”

An initial survey by DNR invasive species staff showed the Turtle Lake infestation extends through about one acre of the 1,600-acre lake. Staff noted the extensive healthy aquatic plant growth in the lake may be limiting the expansion of starry stonewort. As is sometimes the case with starry stonewort, this infestation is concentrated in a shoreline area around a public access. The DNR will explore aggressive treatment options and increased watercraft inspections along with access management in conjunction with the lake association, watershed association and other partners.

”We will use the information we have gathered from the treatments conducted on Lake Koronis to help determine the best course of treatment for Turtle Lake”. Pierce said. “As we move forward with aggressive treatment options we are also working with Beltrami County to increase the level of inspections at the Turtle Lake access. 

“It is important for all Minnesota boaters and anglers to take responsibility at all times and ‘Clean, Drain and Dispose’ as required by law in Minnesota,” she said. “It’s important that everyone using these lakes, or any lake, join this effort and follow this procedure and protect our waters.”

Starry stonewort are grass-like algae that may produce dense mats, which could interfere with use of the lake. The invasive plant also may choke out native plants and possibly alter habitat for young fish. 

The invasive species is typically spread by lake users who transport fragments of the plant from an infested body of water. This new infestation 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.

More information about aquatic invasive species and how to report them is available at www.mndnr.gov/ais.