Bertha Lake

Crow Wing County, Minnesota - DNR stocking history, depth and survey data

Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 18035500

Bertha Lake has no DNR stocking rows in LakeFinder; this page carries its DNR depth, access and survey data.

• Bertha Lake shows no stocking records in Minnesota DNR LakeFinder as of September 2, 2026.
• Maximum depth 64 ft; surface area 337 acres, 142 littoral acres, 3.9 miles of shoreline, per the DNR lake survey.
• Average water clarity (Secchi depth) 15.6 ft.
• Fish species DNR lists here: black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, burbot, greater redhorse, green sunfish, hybrid sunfish, lake whitefish, largemouth bass, northern pike, and 10 more.
• 2 public accesses on the DNR list.
• Most recent DNR fish survey: August 14, 2024 (targeted survey).
• Crow Wing County, nearest town Jenkins; DNR lake number (DOW) 18035500.

Depth map

Bathymetric contours from the Minnesota DNR lake survey mapped 6/6/1960 (topo map/drg); depths in feet. Simplified for the web; not for navigation.

Public accesses

DNR fish survey, 2024

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). Lake Whitefish require a layer of oxythermal habitat that contains water temperatures below 17.2 degrees C (63.0 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on the profile from the deepest basin, the water temperature decreased to below 17.2 degrees C (63.0 degrees F) at 24.5 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 23.7 feet at the time of sampling. The water column did not contain a layer of water with sufficient temperature and dissolved oxygen for Lake Whitefish. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 17.9 degrees C (64.3 degrees F). TDO3 values near 17.2 degrees C (63.0 degrees F) indicate that oxythermal conditions were unsuitable for Lake Whitefish at the time of this survey. Data collected by the Minnesota Department of Natural Resources in 2011-2023 during the late summer thermal stress period, indicate suitable oxythermal habitat in all years surveyed, in contrast with 2024. When inadequate oxythermal habitat is available, Lake Whitefish are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

Minnesota DNR survey narrative, August 14, 2024.

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