Minnesota DNR fisheries surveys · latest July 31, 2023
Mary Lake FishingNRNot rated for water quality
Minnesota DNR surveys at Mary Lake average 14.56 bluegill per unit of sampling effort (CPUE) across 8 surveys. The most recent is a Targeted Survey dated July 31, 2023. Length samples in the latest survey that recorded them ran 3–8 inches. In Hubbard County, Minnesota, Mary 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 18.8 feet of visibility, and the lake has public access. 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.
Species recorded at Mary Lake
14 species on the Minnesota DNR list for this lake. A species on the list has been recorded here; it does not mean it is catchable today or in every part of the lake.
Stocking at Mary Lake
Minnesota DNR publishes a stocking history for this lake — which species went in, how many, and in which years. Read the years: a lake stocked in one year is not necessarily stocked in the next.
Getting on the water
Minnesota DNR lists the public access sites, including ramp type and parking, in the documents below.
Survey results in full
Minnesota DNR surveys at Mary Lake average 14.56 bluegill per unit of sampling effort (CPUE) across 8 surveys. The most recent is a Targeted Survey dated July 31, 2023. Length samples in the latest survey that recorded them ran 3–8 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 Mary Lake — official chemistry is on file, not a letter, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2023-07-31 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Bluegill | 14.56 | 0.16 lb |
| Green Sunfish | 10.40 | 0.25 lb |
| Bluntnose Minnow | 7.34 | — |
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.
Bluegill
Green Sunfish
From the 2023-07-31 survey
A temperature-dissolved oxygen profile was collected in the deepest basin on Big LaSalle Lake on July 31, 2023, to evaluate the amount of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee. Based on the profile, the top of the thermocline (i.e., the location in the water…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mary Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Big LaSalleFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Big LaSalle (1317)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Big LaSalleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Big LaSallePublic Water Access Sites · MN DNR LakeFinder
Common questions
What fish are in Mary Lake?
Minnesota DNR surveys at Mary Lake average 14.56 bluegill per unit of sampling effort (CPUE) across 8 surveys. The most recent is a Targeted Survey dated July 31, 2023. Length samples in the latest survey that recorded them ran 3–8 inches. Minnesota DNR lists 14 species for the lake in total. Those are survey results, not a catch report: a net set on one date measures what was in that net.
When was Mary Lake last surveyed?
The most recent fisheries survey on file for Mary Lake is dated July 31, 2023. 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 Mary Lake stocked?
Minnesota DNR publishes a stocking history for Mary Lake. It records which species were released, in what numbers and in which years — the source documents are linked further down this page. A lake can be stocked in some years and not others, so read the years rather than assuming an annual release.
Does the water-quality grade tell me how Mary 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 Mary Lake — official chemistry is on file, not a letter, and the water-quality trend over 6 years of monitoring is improving. 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.
Where to stay near Mary Lake
Top-rated places to stay near Mary Lake
Planning a trip to Mary Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Mary Lake — straight to your inbox. No spam, unsubscribe anytime.