Brittle Naiad

Invasive SpeciesFound in 13 lakes

Brittle Naiad appears on state infested-waters lists for 13 surface waters. Boaters and anglers moving gear in or out of those lakes carry a clean-drain-dry obligation under state law. 13 lakes — narrow enough that aggressive containment is still on the table. Most upper-Midwest invasives that established here did so quietly over a decade before anyone noticed, so a low number today is not a guarantee for tomorrow.

The presence of Brittle Naiad does not directly change a lake's letter grade — the grade measures the water itself, not the species living in it. Invasive presence is still worth reading alongside the grade.

Total Lakes

Minnesota

Wisconsin

Lakes with Brittle Naiad

Lake	County	State	Grade	Depth
Lac Lavon Lake	Dakota	MN	A	32 ft
Crooked Lake	Adams	WI	B	56 ft
Round Lake	Hennepin	MN	C	37 ft
Bryant Lake	Hennepin	MN	C	45 ft
Ann Lake	Carver	MN	C	45 ft
Mitchell Lake	Hennepin	MN	D	19 ft
Lotus Lake	Carver	MN	D	29 ft
Lake Puckaway	Green Lake	WI	D	5 ft
Mason Lake	Adams	WI	D	9 ft
Buffalo Lake	Marquette	WI	D	8 ft
Susan Lake	Carver	MN	F	17 ft
Staring Lake	Hennepin	MN	F	16 ft
Lake Butte des Morts	Winnebago	WI	NR	9 ft

Frequently Asked Questions

How many lakes have brittle naiad?

Brittle Naiad has been documented in 13 graded lakes: 8 in Minnesota, 5 in Wisconsin.

Does brittle naiad affect water quality?

Invasive species can significantly affect lake ecosystems. They may alter nutrient cycling, displace native species, and change water clarity. Lakes with brittle naiad should be monitored for changes in water quality over time.

Invasives Found With Brittle Naiad

Eurasian Watermilfoil

Co-occurs in 8 lakes · 849 total

Curly-Leaf Pondweed

Co-occurs in 5 lakes · 420 total

Zebra Mussel

Co-occurs in 3 lakes · 667 total

Banded Mystery Snail

Co-occurs in 2 lakes · 362 total

Zebra Mussel

Co-occurs in 2 lakes · 667 total

More on invasive species and lake health

Zebra Mussel Spread: How Many Lakes Are Affected?

Zebra mussel counts from the lakes LakeQuality grades, the counties that show up most often, and the Clean, Drain, Dry rules that still matter.

Lake Water Quality Grades Explained: What A–F Means

How lakes are graded A–F on nutrients and algae using EPA ecoregion condition classes, what each letter means in the water, and why an A is not a clearance.

What to Check Before Buying Lakefront Property

Before you buy lakefront, check the water: clarity trend, nutrient impairment, algae advisories, invasive species, and depth — a data-backed checklist.

Source: EPA National Aquatic Resource Surveys, 2026.