Minnesota DNR fisheries surveys · latest August 14, 2024
Bertha Lake FishingAWater-quality grade A
Minnesota DNR surveys at Bertha Lake average 31.89 bluegill per unit of sampling effort (CPUE) across 11 surveys. The most recent is a Targeted Survey dated August 14, 2024. Length samples in the latest survey that recorded them ran 2–8 inches. In Crow Wing County, Minnesota, Bertha Lake carries an overall water-quality grade of A. Water clarity averages 17.1 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.
Species recorded at Bertha Lake
22 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 Bertha Lake
No stocking record for Bertha 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 Bertha Lake average 31.89 bluegill per unit of sampling effort (CPUE) across 11 surveys. The most recent is a Targeted Survey dated August 14, 2024. Length samples in the latest survey that recorded them ran 2–8 inches.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Bertha Lake A from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is declining. 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: 2024-08-14 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Bluegill | 31.89 | 0.13 lb |
| Bluntnose Minnow | 18.42 | — |
| Tullibee (Cisco) | 15.55 | 0.37 lb |
| Yellow Perch | 8.35 | 0.15 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.
Bluegill
Tullibee (Cisco)
Yellow Perch
From the 2024-08-14 survey
Temperature and dissolved oxygen profiles were collected in the deepest basin in Bertha Lake on August 14, 2024, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Whitefish, the most sensitive coldwater species present in this lake (Cisco are also present).…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Bertha Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BerthaFisheries Lake Survey · MN DNR LakeFinder
Common questions
What fish are in Bertha Lake?
Minnesota DNR surveys at Bertha Lake average 31.89 bluegill per unit of sampling effort (CPUE) across 11 surveys. The most recent is a Targeted Survey dated August 14, 2024. Length samples in the latest survey that recorded them ran 2–8 inches. Minnesota DNR lists 22 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 Bertha Lake last surveyed?
The most recent fisheries survey on file for Bertha Lake is dated August 14, 2024. 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 Bertha Lake stocked?
No stocking record for Bertha 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 Bertha Lake fishes?
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Bertha Lake A from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is declining. 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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