Minnesota DNR fisheries surveys · latest August 3, 2025
Thomas Lake FishingNRNot rated for water quality
Minnesota DNR surveys at Thomas Lake average 8.00 walleye per unit of sampling effort (CPUE) across 4 surveys. The most recent is a Targeted Survey dated August 3, 2025. Length samples in the latest survey that recorded them ran 7–25 inches. In Lake County, Minnesota, Thomas Lake has no letter grade — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Water clarity averages 14.2 feet of visibility. The survey figures on this page are Minnesota DNR's own; the water-quality grade comes from EPA Water Quality Portal samples. Neither is a forecast of today's bite.
Stocking at Thomas Lake
No stocking record for Thomas Lake appears in the Minnesota DNR material on file. That is an absence in the published record, not a confirmation that the lake is unstocked — some waters are managed as naturally reproducing and never appear in a stocking list at all.
Survey results in full
Minnesota DNR surveys at Thomas Lake average 8.00 walleye per unit of sampling effort (CPUE) across 4 surveys. The most recent is a Targeted Survey dated August 3, 2025. Length samples in the latest survey that recorded them ran 7–25 inches.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Thomas Lake — official chemistry is on file, not a letter, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
4 surveys on file from MN DNR Fisheries. Most recent: 2025-08-03 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Walleye | 8.00 | 2.25 lb |
| Tullibee (Cisco) | 7.19 | 0.1 lb |
| White Sucker | 2.05 | 1.92 lb |
| Lake Trout | 1.60 | 3.24 lb |
| Rock Bass | 0.75 | 0.16 lb |
| Northern Pike | 0.69 | 4.23 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE means more abundant in standardized sampling. This is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Walleye
Tullibee (Cisco)
White Sucker
Lake Trout
From the 2025-08-03 survey
Temperature and dissolved oxygen measurements were collected from the deepest basin in Thomas Lake on August 3rd, 2025. This was done to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake (Cisco, also…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Thomas Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ThomasFisheries Lake Survey · MN DNR LakeFinder
Common questions
What fish are in Thomas Lake?
Minnesota DNR surveys at Thomas Lake average 8.00 walleye per unit of sampling effort (CPUE) across 4 surveys. The most recent is a Targeted Survey dated August 3, 2025. Length samples in the latest survey that recorded them ran 7–25 inches. Those are survey results, not a catch report: a net set on one date measures what was in that net.
When was Thomas Lake last surveyed?
The most recent fisheries survey on file for Thomas Lake is dated August 3, 2025. Survey intervals vary by lake and by species; a gap of several years between surveys is normal and does not mean the record is missing.
Is Thomas Lake stocked?
No stocking record for Thomas Lake appears in the Minnesota DNR material on file. That is not the same as a confirmed unstocked lake: it means no stocking document was published for it in the records this page draws on.
Does the water-quality grade tell me how Thomas Lake fishes?
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Thomas Lake — official chemistry is on file, not a letter, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Before you eat what you catch
A water-quality grade is not a consumption advisory. Mercury and PCB advice for Minnesota waters comes from MDH, and it is issued per species and per size class — a lake can grade well and still carry a meal limit on larger predator fish.
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