Big McDonald

Big McDonald Lake is a 935-acre mesotrophic (moderately fertile) lake located in north-central Otter Tail County approximately nine miles west of Perham, MN. Big McDonald Lake is located within the Otter Tail River Watershed. The immediate watershed is primarily composed of agricultural land interspersed with hardwood woodlots. Big McDonald Lake is connected to McDonald (Schwartz) Lake by a navigable channel located along the southeast shoreline. An unnavigable outlet is located along the south shoreline of the lake and connects Big McDonald Lake with Round Lake. Big McDonald Lake has a maximum depth of 46 feet; however, 39% of the lake is less than 15 feet in depth. The secchi disk reading during the 2025 survey was 15.0 feet. Previous secchi disk readings ranged from 9.0 to 14.9 feet. The north and west shorelines of Big McDonald Lake have been extensively developed. Homes, cottages, and resorts compose the development. A DNR owned concrete public water access is located off of County Road 35 along the northwest shoreline of the lake. Shoal water substrates consist primarily of sand and gravel. Large stands of hardstem bulrush are located along the west, south, and east shorelines. Areas of common cattail and wild rice are also scattered along the southwest shoreline. Emergent aquatic plants such as bulrush, cattail, and wild rice provide valuable fish and wildlife habitat, and are critical for maintaining good water quality. Emergent plants provide spawning areas for fish such as Northern Pike, Largemouth Bass, and panfish. They also serve as important nursery areas for all species of fish. Because of their ecological value, emergent plants may not be removed without a DNR permit. To maintain the excellent water quality and angling that this lake has to offer, it is imperative to preserve the quality of the aquatic habitat. Big McDonald Lake can be ecologically classified as a bass-panfish-Walleye type of lake, and this is reflected in the assemblage of the fish community. Walleye, Northern Pike, Largemouth Bass, Black Crappie, and Bluegill are the dominant gamefish species present. The Walleye population continues to be abundant. Several strong year classes are present and should provide good Walleye angling for several years. Walleye ranged in length from 8.7 to 25.9 inches with an average length and weight of 17.9 inches and 2.0 pounds. MN DNR Fisheries maintains the Walleye population at a viable level by stocking Walleye fingerlings on an every-other-year basis. Walleyes exhibit excellent growth rates with an average length of 15.4 inches at four years of age. Northern Pike abundance increased compared to previous surveys and Northern Pike size structure remains poor. Northern Pike ranged in length from 14.3 to 32.4 inches with an average length and weight of 18.9 inches and 1.5 pounds. The Bluegill population is moderately abundant. Bluegill reproduction remains consistently good. A quality size structure exists as 27% of the Bluegills were 8.0 inches or greater in length. Bluegills attain an average length of 7.6 inches at seven years of age. The Largemouth Bass and Black Crappie populations have also been historically abundant with excellent size structures, consistently good reproduction, and average growth. There are no special or experimental fish harvest regulations in effect of Big McDonald Lake. Anglers can maintain the quality of fishing by practicing selective harvest. Selective harvest encourages the release of medium to large fish while allowing the harvest of the more abundant smaller fish for table fare. Releasing the medium to large fish will ensure that the lake will have enough spawning age fish on an annual basis and will provide anglers with more opportunities to catch large fish in the future. Big McDonald Lake was listed as infested with zebra mussels in 2019. Aquatic invasive species are threatening Minnesota waters. The non-native species can potentially harm water quality, water recreation, aquatic habitat, native species, and fish populations. Anglers can help prevent the introduction and spread of invasive species by following watercraft transportation laws.

A targeted survey of nearshore fish species in Big McDonald was conducted on June 26, 2025 by Area Fisheries staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack electrofishing was completed at 14 sampling stations. Similarly, a 50-foot seine was used to sample 11 stations, a 15-foot seine was used at 2 stations and no seine was performed at one station due to dense vegetation. Nearshore sampling captured 17 species of fish including 5 species that are intolerant of disturbance (i.e., Mimic Shiner and Rock Bass) and 2 that are tolerant of disturbance (i.e., Black Bullhead and Green Sunfish). The nearshore data were combined with trap net and gill net data from a August 2025 survey to describe the fish community and provide a fish- based (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., Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g., Green Sunfish and Common Carp). 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 site. Results from this survey provide evidence that the fish community in Big McDonald is healthy as indicated by an FIBI score (47) above the general use impairment threshold (45) for aquatic life use determined for similar lakes. These results differ from previous findings, which had a FIBI score below the impairment threshold. The survey results will be considered when the biological health of the lake is assessed during the Ottertail River Watershed assessment process, which will be completed in coordination with MN Pollution Control Agency. You can help protect the fish community in Big McDonald by reducing runoff, maintaining natural shorelines, and preventing the spread of invasive species.

Big McDonald Lake is a 935-acre mesotrophic (moderately fertile) lake located in north-central Otter Tail County approximately nine miles west of Perham, MN. Big McDonald Lake is located within the Otter Tail River Watershed. The immediate watershed is composed primarily of agricultural land interspersed with hardwood woodlots. Big McDonald Lake is connected to McDonald (Schwartz) Lake by a navigable channel located along the southeast shoreline. An unnavigable outlet is located along the south shoreline of the lake and connects Big McDonald Lake with Round Lake. The maximum depth of Big McDonald Lake is 46 feet; however, 39% of the lake is less than 15 feet in depth. The secchi disk reading during the 2021 survey was 14.9 feet. Previous secchi disk readings ranged from 9.0 to 13.9 feet. The north and west shorelines of Big McDonald Lake have been extensively developed. Homes, cottages, and resorts compose the majority of the development. A DNR owned concrete public water access is located off of County Road 35 along the northwest shoreline of the lake. The shoal water substrates consist primarily of sand and gravel. Large stands of hardstem bulrush are located along the west, south, and east shorelines. Areas of common cattail and wild rice are also scattered along the southwest shoreline. Emergent aquatic plants such as bulrush, cattail, and wild rice provide valuable fish and wildlife habitat, and are critical for maintaining good water quality. Emergent plants provide spawning areas for fish such as Northern Pike, Largemouth Bass, and panfish. They also serve as important nursery areas for all species of fish. Because of their ecological value, emergent plants may not be removed without a DNR permit. To maintain the excellent water quality and angling that this lake has to offer, it is imperative to preserve the quality of the aquatic habitat. Big McDonald Lake can be ecologically classified as a bass-panfish-Walleye type of lake and this is reflected in the assemblage of the fish community. Walleye, Northern Pike, Largemouth Bass, Black Crappie, and Bluegill are the dominant gamefish species present. The Walleye population continues to be abundant. Several strong year classes are present and should provide good Walleye angling for several years. Walleyes ranged in length from 9.4 to 26.0 inches with an average length and weight of 16.3 inches and 1.6 pounds. Walleyes exhibit excellent growth rates with an average length of 15.2 inches at four years of age. Northern Pike abundance has remained at a moderate density and age data indicate that natural reproduction continues to be consistently good. Northern Pike ranged in length from 15.2 to 26.9 inches with an average length and weight of 20.1 inches and 1.7 pounds. Pike growth is slow with an average length of 19.2 inches at four years of age. The Bluegill population is moderately abundant. A quality size structure exists as 26% of the Bluegills were 8.0 inches or greater in length. Bluegills attain an average length of 7.8 inches at seven years of age. The Largemouth Bass and Black Crappie populations have also been historically abundant with excellent size structures, consistently good reproduction, and average growth. Anglers can maintain the quality of fishing by practicing selective harvest. Selective harvest encourages the release of medium to large-size fish while allowing the harvest of the more abundant smaller fish for table fare. Releasing the medium to large fish will ensure that the lake will have enough spawning age fish on an annual basis and will provide anglers with more opportunities to catch large fish in the future. Big McDonald Lake was listed as infested with zebra mussels in 2019. Aquatic invasive species are threatening Minnesota waters. The non-native species can potentially harm water quality, water recreation, aquatic habitat, native species, and fish populations. Anglers can help prevent the introduction and spread of invasive species by following watercraft transportation laws.

Based on Minnesota DNR survey data, anglers target Hybrid Sunfish, Walleye, Largemouth Bass, Rock Bass, and Black Crappie in Big McDonald. See the full species list above for catch rates, size structure, and quality scores.

Minnesota DNR records list public access for Big McDonald. Check the DNR LakeFinder page for the launch type and directions before you go.

Big McDonald has a maximum depth of 46 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Big McDonald is from 2025.

Yes — Big McDonald has confirmed zebra mussel. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.