Fish Study Results Available
2025 DNR Survey · See News
A first for Grace Lake
Curly-leaf pondweed has been found in our lake.
In July 2025, a single curly-leaf pondweed specimen was recovered during Minnesota DNR fisheries sampling in Grace Lake's southeast bay — the first aquatic invasive plant ever confirmed in the lake. What comes next depends on us.
Latest update · June 17, 2026
Spring survey underway — early results encouraging
LimnoPro began their spring point-intercept survey on Wednesday, June 17. It is not yet finished, but of the first 60 points sampled that day, curly-leaf pondweed was found at only one — rooted and actively growing in front of the public access. The crew re-checked the 2025 MN DNR detection points and found no CLP there or nearby. These results are still very preliminary; the survey resumes the following week. See the full timeline below for details.
01 / The DiscoveryA fragment in a gill net.
What the MN DNR found, when they found it, and how we confirmed it.
On a routine fisheries sampling day in July 2025, biologists from the Minnesota Department of Natural Resources were working the southeast bay of Grace Lake when they pulled a gill net that contained something unexpected: a small, wavy-leafed plant fragment tangled in the mesh.
The specimen was photographed and sent to the MN DNR's Ecological Water and Resources Invasive Species group, which confirmed the identification as curly-leaf pondweed (Potamogeton crispus) and logged the record on the national EDDMapS invasive species database at coordinates 47.4049568, -94.735212, in about 10 feet of water.
Approximately one month later, between August 20–25, 2025, Limnopro Aquatic Science completed a full point-intercept survey of Grace Lake on behalf of the Grace Lake Watershed Improvement Association. Because that survey happened in late summer, it was too late in the season to find CLP — the plant dies back in early July. The Limnopro team did, however, uncover the EDDMapS record while researching the lake's history. That is how this all came to the board's attention.
The colored band around Grace Lake is the littoral zone — where water is shallow enough for plants to grow. Red areas show the densest plant cover (the “weedline”); the deep blue center is too deep for rooted plants. The CLP specimen was recovered in the southeast bay, well within the plant-growth zone. Source: Limnopro 2025 Aquatic Plant Survey, biovolume percent map (Appendix A).
A non-native aquatic plant from Eurasia with an unusual life cycle that lets it get ahead of everything else.
Curly-leaf pondweed (CLP) is a submerged aquatic plant native to Europe, Asia, Africa, and Australia. It was first introduced to North America in the mid-1800s and has been working its way through Minnesota's waters for over a century. Within a 30-mile radius of Grace Lake, it has already been documented in at least 11 locations across Clearwater, Hubbard, Itasca, and Cass counties, with records dating from 1976 to 2025.
Field identification comes down to one unmistakable feature: the leaves.
Alternating along the stem. Leaves attach one at a time on opposite sides of the stem — never in pairs. The stem is often reddish-brown.
The “lasagna noodle” edge. Leaves are oblong with rippled, wavy margins and fine teeth along the edge. Tips are rounded, not pointed.
Olive-green, turning bronze. Leaves are shiny olive-green in spring, often turning reddish-bronze before the plant dies back in early July.
Actual photos of the curly-leaf pondweed specimen recovered from Grace Lake in July 2025. Young spring growth can look misleadingly like a native pondweed — take photos from multiple angles, showing both the whole plant and a close-up of the leaf edge.
Things to look for on the water
Wavy, rippled leaf margins — the edges undulate like a lasagna noodle or crinkle-cut potato chip.
Fine teeth along the leaf edge — visible up close, distinguishing it from smooth-edged native pondweeds.
Rounded leaf tips — not pointed; each leaf is 2–4 inches long.
Olive-green to reddish-brown color — especially when the plant is stressed or heading toward die-back in late June.
Leaves alternate along the stem — spaced, not whorled in circles.
Often the first plant up — if something is knee-high in April or early May before most other plants are going, look twice.
03 / The Life CycleWhy spring is everything.
Curly-leaf pondweed runs its whole calendar backwards. Understanding this is the single most important thing for spotting it.
Almost every aquatic plant in Minnesota waits for warm water. Native pondweeds, milfoils, coontail, and naiads start growing once the water reaches about 60°F, which in our part of the state means early June. They peak in July and August.
Curly-leaf pondweed does the opposite. Its seed-like "turions" sprout in the fall, the plants grow slowly under the ice all winter, and by April they're already several inches tall. By May and June they dominate. Then, just as natives are hitting their stride in early July, curly-leaf dies back — often dramatically — leaving behind a mat of decomposing plant material that can dump nutrients into the water and fuel late-summer algae blooms.
Curly-leaf pondweed reaches full size in May and June when natives are barely starting. By early July it has died back to the lake bottom — the main reason the Limnopro survey couldn't find it in late August. Your window to spot it is roughly late April through mid-June.
04 / The ImpactWhy lakes worry about it.
CLP doesn't always become a nuisance — but when it does, the effects are real.
On the water
Forms dense surface mats in spring that tangle propellers, foul fishing lines, and block swim areas.
Crowds out native plants that would otherwise occupy the same shallow habitat in spring.
In the water
Sudden July die-off releases nutrients — a trigger for algae blooms later in summer.
Decomposition can draw down dissolved oxygen in localized areas, stressing fish.
The severity depends heavily on how much CLP establishes and where. A few scattered plants in a bay do almost nothing measurable. A contiguous infestation across many acres changes a lake's character. That's why this matters now, while the Grace Lake find is still a single point on a map.
05 / The Good NewsGrace Lake is still in remarkable shape.
Before the alarm bells get too loud, a reality check from the 2025 survey: this is a healthy, diverse Northwoods lake with strong native vegetation and above-average water clarity.
23
native aquatic plant species found in 2025 (up from 20 in 2007)
91%
of sampled sites had native plant growth
340
acres of littoral (plant-growing) habitat on the lake
0
other invasive plants detected — no EWM, no starry stonewort, no zebra mussels
What the 18-year comparison tells us
The 2025 Limnopro survey compared directly to the last full plant survey the MN DNR did on Grace Lake in 2007. Eighteen years apart, the plant community has held together remarkably well. Shallow coverage barely changed (96→91 percent), the dominant species kept their ranking (naiad is still king, as it was in 2007), and native diversity edged slightly upward. Several species — Canada waterweed, sago pondweed, northern watermilfoil — actually increased in frequency, which the report attributes to sustained water clarity extending the growing season.
Translation: the ecosystem is resilient. A single CLP specimen is a warning, not a crisis. Early action matters precisely because the lake isn't compromised yet.
06 / The PlanWhat the Association is doing next.
A grant, two surveys, and a decision point. Here is how the next 18 months are structured.
July 2025 · completed
CLP specimen recovered by MN DNR fisheries
Single fragment in the southeast bay. Verified by MN DNR Ecological Water and Resources Invasive Species group; logged to EDDMapS.
August 2025 · completed
Limnopro full point-intercept survey
340 sampling points across the littoral zone. Confirmed 23 native species and no invasive plants — though too late in the season for CLP detection.
May 30, 2026 · completed
Resident briefing & spring-watch update at 2026 Annual Meeting
The 2026 Annual Meeting was held at Bible Camp. Members received a CLP update, the MN DNR presented 2025 fish survey results (which confirmed the CLP fragment found in July 2025), and residents were asked to continue watching the shallows through early summer.
Began June 17, 2026 · in progress
Spring point-intercept + CLP pre-delineation survey
LimnoPro returned to Grace Lake for a dedicated spring-timed Point Intercept Study and a Pre-Delineation Survey for CLP — timed to catch it at peak growth. The survey began Wednesday, June 17 and is not yet complete. Early results are encouraging: of the first 60 points sampled that day, CLP was found at only one — rooted and actively growing in front of the public access. The crew also re-checked the points where the MN DNR recovered CLP in 2025 and found no curly-leaf there or nearby. These findings are still very preliminary; the survey resumes the following week, and any CLP colonies found will be precisely mapped to give us the exact acreage and locations of all established plants.
Summer–Fall 2026
Data review & management options
Based on what we find, the board — with Limnopro's guidance — evaluates options: hand-pulling for very small infestations, targeted herbicide (endothall or diquat) for larger areas, or continued monitoring if the scope stays small.
Spring 2027
Management action (if warranted)
Any treatment is implemented in spring, timed to CLP's active growth period and before native plants are fully up, to protect the existing native community.
About the grant
The Grace Lake Watershed Improvement Association has secured a $5,000 grant to fund CLP response efforts. This will go primarily toward the 2026 spring survey, and any management in 2027, if needed, may require additional funding.
07 / Your PartWhat you can do.
The most valuable thing a resident can contribute is eyes on the water between late April and mid-June. Here is how to help.
1. Watch the shallows from mid-April through early July
From roughly mid-April through early July 2026, take a few minutes when you're at the dock — or out boating, kayaking, or swimming — to scan the shallows. CLP prefers 2–10 feet of water, so you can often see it from the surface or with a mask. Look for any plant that seems ahead of everything else — knee-high when natives are barely up — with wavy, serrated leaves.
2. If you see something suspicious, photograph it
Take several clear photos: one wide shot showing the plant in context, one close-up of a leaf showing the wavy margin, and — if you can reach it — a photo of the whole stem. Don't pull the plant up and move it; a tiny fragment can start a new colony elsewhere. If you want a specimen, cut a short stem and drop it in a sealed bag for same-day delivery.
3. Report it
Send photos with the approximate location (GPS coordinates or a dropped pin on a map app, plus the nearest landmark) to the Grace Lake Watershed Improvement Association through gracelakebemidji.com. The Association will coordinate identification with our lake scientists and, if confirmed, log the find to the MN DNR's EDDMapS database. You can also log it yourself at eddmaps.org.
4. Clean, drain, dry — every time
Grace Lake is less than 30 miles from confirmed populations of CLP (11 locations), Eurasian watermilfoil (9 locations), starry stonewort (20 locations), and zebra mussels (71 locations). The same boats and trailers that bring your friends and family up for the weekend are the most likely vector for any of these. Before any boat leaves or enters Grace Lake: visibly inspect the hull, trailer, and live wells; drain everything; let it dry in the sun for at least five days before launching in another lake. This is the single biggest thing any one person can do to protect the lake.
5. Help fund the response
A $5,000 grant covers the 2026 spring survey, but any management work in 2027 — and our ongoing boat-landing inspection program — will need additional funding. Landing inspections have kept Grace Lake free of zebra mussels, starry stonewort, Eurasian milfoil, and everything else for years, and we want to keep them going. Can you give an additional $250–$500 this year? Every dollar goes directly toward protecting the lake. Donate through the Association at gracelakebemidji.com.
08 / ResourcesGo deeper.
The full scientific report, the detailed search-area map, and trusted outside sources.
Grace Lake Watershed Improvement Association
Our homepage — meeting details, board contacts, donation and membership links, boat-landing inspection program, and ongoing lake-protection work.
The complete scientific report prepared by Daniel C. McEwen, Ph.D., CLP. 8 pages plus appendices including biovolume maps, canopy depth, sediment, and a plant atlas.
Visit the website for board contacts, meeting information, donation links, the boat-landing inspection schedule, and additional lake-protection resources.
Report a Suspected CLP Sighting
Found something suspicious in the shallows?
1. Photograph it — both a wide shot and a close-up of the leaf edge.
2. Note the location — GPS pin if you can, otherwise nearest landmark or dock number.
Every contribution goes directly to lake protection.
The Association runs the boat-landing inspection program that has kept Grace Lake free of zebra mussels and other AIS for years. Your donations — suggested $250–$500 this year — keep inspections staffed and fund the 2026–2027 CLP response. Give through gracelakebemidji.com.
Grant Administration & Disclosure
2026 Invasive Aquatic Plant Management Project
Curly-leaf pondweed response · Grace in Hubbard County 2026
This project is primarily funded by a state grant appropriation from the Minnesota Department of Natural Resources (DNR). Per state grant requirements, the following individuals are responsible for the leadership and management of this grant on behalf of the Grace Lake Watershed Improvement Association.
Citation: Limnopro Aquatic Science, Inc. 2025. Grace Lake Plant Survey. Prepared for Grace Lake Watershed Improvement Association. 8 pp with appendices. This resident briefing summarizes and extends the full Limnopro report. All scientific findings are attributed to the original authors. Prepared for the 2026 Annual Meeting.
