Willmert (Main Bay) Lake
Martin County, Minnesota - DNR stocking history, depth and survey data
Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 46001401
DNR records show 8 stocking entries at Willmert (Main Bay) Lake since 2016, most recently northern pike fingerlings in 2025 (680 fish).
- Willmert (Main Bay) Lake has 8 DNR stocking records across 6 years (2016-2025): walleye (5), northern pike (3).
- The most-stocked species by count is walleye: 905,000 fish on record.
- Maximum depth 8 ft; surface area 335 acres, 335 littoral acres, 3.3 miles of shoreline, per the DNR lake survey.
- Average water clarity (Secchi depth) 0.8 ft.
- Fish species DNR lists here: bigmouth buffalo, black bullhead, black crappie, common carp, freshwater drum, largemouth bass, orangespotted sunfish, walleye, white crappie, white sucker, yellow perch.
- 1 public access on the DNR list.
- Most recent DNR fish survey: (targeted survey).
- Martin County, nearest town Fairmont; DNR lake number (DOW) 46001401.
Stocking history
| Year | Species | Size | Number | Pounds |
|---|---|---|---|---|
| 2025 | Northern Pike | fingerlings | 680 | 170.0 |
| 2025 | Walleye | fry | 181,000 | 1.5 |
| 2023 | Walleye | fry | 181,000 | 1.4 |
| 2021 | Northern Pike | fingerlings | 362 | 254.9 |
| 2021 | Walleye | fry | 181,000 | 1.4 |
| 2019 | Walleye | fry | 181,000 | 1.4 |
| 2017 | Walleye | fry | 181,000 | 1.6 |
| 2016 | Northern Pike | fingerlings | 986 | 27.4 |
Field note · Minnesota stocks by year, not by truck day: walleye fry go in within weeks of ice-out, fingerlings and yearlings mostly in fall, and stream trout in spring and fall. A row here means the fish went in during that year; DNR adds the year's rows after the fact, so the current year can look empty until winter.
Public accesses
| Type | Owner | Where |
|---|---|---|
| asphalt ramp | Minnesota DNR | - Needs maintenance. Gravel on top of access ramp cansirg truck tires to spin out when loading out boat. |
DNR fish survey, 2019
| Species | Gear | Catch per net | Total catch | Avg lb |
|---|---|---|---|---|
| Yellow perch | 50-ft beach seine | 280.80 | 2,808 | 0.00 |
| Bigmouth buffalo | 50-ft beach seine | 15.50 | 155 | 0.00 |
| Black bullhead | 50-ft beach seine | 3.40 | 34 | 0.00 |
| White crappie | 50-ft beach seine | 0.60 | 6 | 0.00 |
| Largemouth bass | 50-ft beach seine | 0.20 | 2 | 0.00 |
| Black crappie | 50-ft beach seine | 0.20 | 2 | 0.00 |
| Orangespotted sunfish | 50-ft beach seine | 0.10 | 1 | 0.00 |
| Yellow perch | Backpack electrofishing | 28.98 | 41 | 0.00 |
| Fathead minnow | Backpack electrofishing | 14.84 | 21 | 0.00 |
| Black bullhead | Backpack electrofishing | 11.31 | 16 | 0.00 |
| Bigmouth buffalo | Backpack electrofishing | 11.31 | 16 | 0.00 |
| Orangespotted sunfish | Backpack electrofishing | 8.48 | 12 | 0.00 |
| Spotfin shiner | Backpack electrofishing | 4.24 | 6 | 0.00 |
| White crappie | Backpack electrofishing | 2.12 | 3 | 0.00 |
| Black crappie | Backpack electrofishing | 0.71 | 1 | 0.00 |
Catch per net (CPUE) is the DNR survey's count per gill net or trap net set; higher means more of that species were sampled, not a fishing forecast. Top species per gear shown; where we have no verified common name for a DNR code, the code itself is shown.
A targeted survey of the nearshore fish community in Wilmert Lake was conducted by Fisheries Index of Biological Integrity (IBI) Program Staff starting June 24, 2019. Ten sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 50-foot seine. Nearshore sampling captured 9 native species of fish. None of these species are intolerant of disturbance and four species are tolerant of disturbance (Bigmouth Buffalo, Black Bullhead, Fathead Minnow, and Orangespotted Sunfish). Data from this targeted nearshore survey is combined with trap net and gill net data from an August 2018 standard survey to describe the fish community and provide a Fish-based Index of Biological Integrity (FIBI) score. The FIBI uses fish community data to measure a lake's health, and the types of fish species present can help identify any stressors that may be negatively affecting the lake environment. In Minnesota lakes, certain fish species cannot survive without clean water and a healthy habitat (e.g., Iowa Darter and Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead and Fathead Minnow). The FIBI score, composed of several fish community diversity and composition metrics, indicates the overall health of a lake by comparing it to what is expected for a healthy lake. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Data from this survey will contributed biological information about the health of the fish community in Wilmert Lake to the Blue Earth River Watershed assessment of surface waters process completed in coordination with MN Pollution Control Agency.
Minnesota DNR survey narrative, .
All Minnesota stockings · every Minnesota lake with a page · state CSV · this lake on DNR LakeFinder
Stocking rows, depths, accesses and survey figures are Minnesota DNR LakeFinder data as of 2026-09-02. Regulations, slot limits and special rules are on the DNR page linked above, not here.
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