Rudd
Invasive SpeciesFound in 6 lakes
Rudd appears on state infested-waters lists for 6 surface waters. Boaters and anglers moving gear in or out of those lakes carry a clean-drain-dry obligation under state law. 6 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 Rudd does not directly change a lake's LakeGrade rubric score — the grade measures the water itself, not the species inhabiting it. But invasive presence is a meaningful adjacent signal worth reading alongside the grade.
Lakes with Rudd
| Lake | County | State | Grade | Depth |
|---|---|---|---|---|
| Oconomowoc Lake | Waukesha | WI | B | 60 ft |
| Oconomowoc Lake Site | Waukesha | WI | B | 60 ft |
| Lower Nashotah Lake | Waukesha | WI | B | 43 ft |
| Fowler Lake | Waukesha | WI | B | 50 ft |
| Ocauchee Lake | Waukesha | WI | B | 90 ft |
| Mark Twain Lake | Monroe | MO | B | - |
Frequently Asked Questions
How many lakes have rudd?
Rudd has been documented in 6 graded lakes: 5 in Wisconsin, 1 in Missouri.
Does rudd affect water quality?
Invasive species can significantly affect lake ecosystems. They may alter nutrient cycling, displace native species, and change water clarity. Lakes with rudd should be monitored for changes in water quality over time.
Invasives Found With Rudd
Source: EPA National Aquatic Resource Surveys, 2026.