Minnesota DNR fisheries surveys · latest May 12, 2025
Blue Lake FishingDWater-quality grade D
Minnesota DNR surveys at Blue Lake average 22.58 largemouth bass per unit of sampling effort (CPUE) across 11 surveys. The most recent is a Targeted Survey dated May 12, 2025. Length samples in the latest survey that recorded them ran 6–19 inches. In Isanti County, Minnesota, Blue Lake carries an overall water-quality grade of D. Water clarity averages 8.9 feet of visibility, and there are 2 public boat landings. 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 Blue Lake
13 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 Blue 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
2 public boat landings are recorded on Blue Lake. Minnesota DNR lists the public access sites, including ramp type and parking, in the documents below.
Survey results in full
Minnesota DNR surveys at Blue Lake average 22.58 largemouth bass per unit of sampling effort (CPUE) across 11 surveys. The most recent is a Targeted Survey dated May 12, 2025. Length samples in the latest survey that recorded them ran 6–19 inches.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Blue Lake D from EPA Water Quality Portal chemistry, 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
11 surveys on file from MN DNR Fisheries. Most recent: 2025-05-12 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Black Crappie | 85.95 | 0.19 lb |
| Largemouth Bass | 22.58 | 0.84 lb |
| Bluegill | 20.44 | 0.14 lb |
| Bluntnose Minnow | 19.27 | — |
| Yellow Perch | 10.59 | 0.11 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.
Black Crappie
Largemouth Bass
Bluegill
Yellow Perch
From the 2025-05-12 survey
Blue Lake is a 263-acre lake in southwest Isanti County located five miles northeast of Zimmerman and is within the Rum River watershed. It has a maximum depth of 31 feet and 51 percent of the lake is less than 15 feet deep (134 acres). Water clarity in May and June can be 6 to 9 feet; however, it becomes low in…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Blue Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BlueFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Blue (1850)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — BlueFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BluePublic Water Access Sites · MN DNR LakeFinder
Common questions
What fish are in Blue Lake?
Minnesota DNR surveys at Blue Lake average 22.58 largemouth bass per unit of sampling effort (CPUE) across 11 surveys. The most recent is a Targeted Survey dated May 12, 2025. Length samples in the latest survey that recorded them ran 6–19 inches. Minnesota DNR lists 13 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 Blue Lake last surveyed?
The most recent fisheries survey on file for Blue Lake is dated May 12, 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 Blue Lake stocked?
Minnesota DNR publishes a stocking history for Blue 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 Blue Lake fishes?
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Blue Lake D from EPA Water Quality Portal chemistry, 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 Blue Lake
Top-rated places to stay near Blue Lake
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