Minnesota DNR fisheries surveys · latest July 17, 2023
Blackwater Lake FishingAWater-quality grade A
Minnesota DNR surveys at Blackwater Lake average 15.41 largemouth bass per unit of sampling effort (CPUE) across 13 surveys. The most recent is a Standard Survey dated July 17, 2023. Length samples in the latest survey that recorded them ran 5–17 inches. In Cass County, Minnesota, Blackwater Lake carries an overall water-quality grade of A. Water clarity averages 14.1 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 Blackwater Lake
16 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 Blackwater 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 Blackwater Lake average 15.41 largemouth bass per unit of sampling effort (CPUE) across 13 surveys. The most recent is a Standard Survey dated July 17, 2023. Length samples in the latest survey that recorded them ran 5–17 inches.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Blackwater 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
13 surveys on file from MN DNR Fisheries. Most recent: 2023-07-17 (Standard Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Bluegill | 19.10 | 0.15 lb |
| Largemouth Bass | 15.41 | 0.98 lb |
| Bluntnose Minnow | 13.57 | — |
| Yellow Perch | 6.71 | 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
Largemouth Bass
Yellow Perch
From the 2023-07-17 survey
Blackwater Lake is a 767-acre lake with 7.6 miles of shoreline and a maximum depth of 67 feet located southwest of Longville, MN. A DNR owned public access is located on the northeast shore. The DNR has classified Minnesota's lakes into 43 different classes based on physical, chemical, and other characteristics.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Blackwater Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BlackwaterFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Blackwater (1597)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — BlackwaterFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BlackwaterPublic Water Access Sites · MN DNR LakeFinder
Common questions
What fish are in Blackwater Lake?
Minnesota DNR surveys at Blackwater Lake average 15.41 largemouth bass per unit of sampling effort (CPUE) across 13 surveys. The most recent is a Standard Survey dated July 17, 2023. Length samples in the latest survey that recorded them ran 5–17 inches. Minnesota DNR lists 16 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 Blackwater Lake last surveyed?
The most recent fisheries survey on file for Blackwater Lake is dated July 17, 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 Blackwater Lake stocked?
Minnesota DNR publishes a stocking history for Blackwater 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 Blackwater Lake fishes?
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Blackwater 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.
Where to stay near Blackwater Lake
Top-rated places to stay near Blackwater Lake
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