Donalds Lake is a 168-acre mesotrophic (moderately fertile) lake located in central Otter Tail County and within the city limits of Ottertail City, Minnesota. The maximum depth is 43 feet and 50% of the lake is 15 feet or less in depth. The secchi disk reading was 14.5 feet. Previous secchi disk reading have ranged from 6.0 to 15.0 feet.
Moderate development exists around Donalds Lake. The public access, which is located on the west shoreline, is owned by the city. Parking is limited and access is gained by navigating off of a city street. The shoal water substrates consist primarily of sand and gravel. Emergent vegetation (hardstem bulrush, common cattail, and wild rice) is located in various areas throughout the lake. Emergent aquatic plants such as bulrush and cattail provide valuable fish and wildlife habitat, and are critical for maintaining good water quality. They protect shorelines and lake bottoms, and can actually absorb and break down polluting chemicals. 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.
Recent lake survey data indicate that Donalds Lake has viable populations of Walleye, Northern Pike, and Bluegill.
Walleye ranged in length from 9.2 to 21.0 inches with an average length and weight of 17.6 inches and 2.2 pounds.
A moderate density Northern Pike population exists. Age and length data indicate that Northern Pike reproduction is consistently good. Northern Pike ranged in length from 13.2 to 34.5 inches with an average length and weight of 19.1 inches and 1.5 pounds. Northern Pike attain an average length of 22.5 inches at five years of age.
The long-term trend has been an increase in Bluegill abundance. Age data indicate that Bluegill reproduction is consistently good. Twenty-four percent of the Bluegills were 7.0 inches or greater in length. Bluegills attain an average length of 6.6 inches at six years of age.
Anglers can maintain or improve the quality of fishing for all species of fish in Donalds Lake 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 opportunities to catch more large fish in the future.