Island Lake (Mahnomen County)

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

Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 44003800

DNR records show 12 stocking entries at Island Lake (Mahnomen County) since 2017, most recently walleye fingerlings in 2025 (11,730 fish).

• Island Lake (Mahnomen County) has 12 DNR stocking records across 5 years (2017-2025): walleye (12).
• The most-stocked species by count is walleye: 106,099 fish on record.
• Maximum depth 43 ft; surface area 616 acres, 331 littoral acres, 9.4 miles of shoreline, per the DNR lake survey.
• Average water clarity (Secchi depth) 6.7 ft.
• Fish species DNR lists here: black bullhead, black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, yellow perch.
• 1 public access on the DNR list.
• Most recent DNR fish survey: July 21, 2025 (standard survey).
• Mahnomen County, nearest town Lengby; DNR lake number (DOW) 44003800.

Depth map

Bathymetric contours from the Minnesota DNR lake survey mapped 8/17/1971 (orig map); depths in feet. Simplified for the web; not for navigation.

Stocking history

⁶ fish cooperatively purchased, raised, and/or stocked by White Earth Nation.

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.

Island Lake is a 616-acre, class-25 lake located in northern Mahnomen County within the boundaries of the White Earth Indian Reservation. The lake sits within the North Central Hardwood Forests ecoregion in the upper reaches of the Wild Rice River Watershed. Island Lake has a littoral area of 331 acres and a heavily developed shoreline. There is a public boat access on the east shoreline. Island Lake's fish community has undergone many changes since it was initially surveyed in 1953 including large fluctuations in game and non-game fish species. The MN DNR Detroit Lakes Fisheries Office and the White Earth Natural Resources (WENR) Office work in partnership to stock Walleye fingerlings in odd-numbered years. A standard fisheries survey was completed in July 2025 to assess the fish populations in Island Lake. Anglers will find a moderate abundance of Northern Pike in Island Lake, with a good opportunity to catch decent fish. The Northern Pike gill net catch rate of 11.6 pike per gill net in 2025 was up from the 8.1 pike per net in the 2020 survey. Size structure was better than other lakes in the Detroit Lakes work area with 50% of pike above 22 inches in length and about 36% of the pike greater than 24 inches. The average length of Northern Pike surveyed in 2025 was 23 inches and the longest was almost 36 inches. Walleye numbers were down with 3.7 Walleye per gill net sampled, which is below the lake's average. Walleye size is good compared to other area lakes. Ninety-four percent of the Walleye captured in 2025 were over 15 inches and 48% were over 20 inches. Walleyes up to almost 28 inches were sampled. Bluegill numbers were at a near record high for the lake. Bluegills of all sizes were observed but tend to run small. Only 1% of the Bluegill caught in trap nets were over eight inches, but the longest Bluegill measured was 10.3 inches. Black Crappie were plentiful in trap nets, however these fish only averaged 8.5 inches. The longest crappie measured was 10.25 inches. Largemouth Bass were captured in low numbers in the trap nets, which is often the case with this sampling gear. One Largemouth Bass almost 19 inches was captured in a gill net. Other fish species sampled were Black and Brown Bullhead, hybrid sunfish, Pumpkinseed, and Rock Bass.

Minnesota DNR survey narrative, July 21, 2025.

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