Topper Lake

Cook County, Minnesota - DNR stocking history, depth and survey data

Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 16033600

DNR records show 7 stocking entries at Topper Lake since 2016, most recently brook trout fingerlings in 2025 (2,500 fish).

• Topper Lake has 7 DNR stocking records across 7 years (2016-2025): brook trout (7).
• The most-stocked species by count is brook trout: 15,232 fish on record.
• Maximum depth 28 ft; surface area 47 acres, 28 littoral acres, 1.3 miles of shoreline, per the DNR lake survey.
• Average water clarity (Secchi depth) 9.7 ft.
• Fish species DNR lists here: brook trout.
• 2 public accesses on the DNR list.
• Most recent DNR fish survey: June 9, 2025 (standard survey).
• Cook County, nearest town Grand Marais; DNR lake number (DOW) 16033600.

Stocking history

⁸ fish cooperatively purchased, raised, and/or stocked by U.S. Fish and Wildlife Service.

Public accesses

DNR fish survey, 2025

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.

Topper Lake is a small, 47-acre lake with a maximum depth of 28.0 feet and is located completely within the Boundary Waters Canoe Area Wilderness (BWCAW). Access to the lake is considered moderate, with a relatively short 0.5-mile portage over a small hill from the Mayhew Lake Road spur trail. Water temperatures and dissolved oxygen concentrations in Topper Lake have supported conditions that are suitable for stocked trout during the summertime. Topper Lake has been managed for brook trout since 1971 and is currently stocked annually with 2,500 fingerlings during the fall. The long-range goal for brook trout is to maintain a minimum gillnet catch of 10.0 fish/net with two-year classes of fish greater than 10.0 inches present. In 2025, a standard survey was conducted on Topper Lake to monitor the brook trout population. The 2025 brook trout catch rate from gillnets was the lowest recorded at 2.5 fish/net and was well below the long-term median for the lake. Brook trout lengths ranged from 6.2 to 15.2 inches, with an average length of 10.2 inches. Less than half of the catch was greater than 10.0 inches, providing below average size structure compared to other area lakes. Aging results only found fish from the last three stocking events (2021, 2023, 2024). No brook trout were stocked in 2022 due to fish shortages and may have contributed to the low catch rate observed in 2025. It is unclear how significant the missed year class from 2022 influenced the catch rates during the 2025 survey or if the population has declined from the last survey. Brook trout growth in Topper Lake was fair, taking two years to reach 10.7 inches on average. Temperature and dissolved oxygen monitoring found suitable habitat for brook trout that does not appear to be limiting brook trout populations within the lake. Anglers looking to fish Topper Lake may find lower catches of brook trout that are smaller in size. Minnesota Lakes within Cook County continue to be susceptible to aquatic invasive species introductions. Invasive species have the potential to significantly alter fish communities and overall lake health. Anglers should clean watercraft and fishing gear, drain all water, and dispose of unused bait in the trash to prevent accidental introductions.

Minnesota DNR survey narrative, June 9, 2025.

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