Oscar

A mark-recapture population estimate of Muskies took place on Oscar Lake during the springs of 2024 and 2025 using passive integrated transponder (PIT) tags. Fish were sampled via electrofishing. A total of 63 individual fish were PIT tagged between the two years. Lengths ranged from 17.1 to 52.8 inches; average length was 40.3 inches. The population estimate was 118 adult (30 inches or greater) muskies, equating to an adult Muskie for every 8.3 surface acres (4.0 littoral acres).

Oscar Lake is managed as a low-density Muskie fishery. Past surveys have captured too few fish to generate a population estimate. A mark-recapture population estimate of Muskies began in spring of 2024 using passive integrated transponder (PIT) tags. Fish were sampled using nighttime electrofishing. A total of 36 individual Muskies were PIT tagged ranging in length from 17.1 to 52.8 inches; average length was 40.0 inches. The recapture phase will begin in spring of 2025 using exclusively electrofishing.

Oscar Lake is a shallow, moderately productive basin located four miles west of Holmes City in Douglas County. Surface acreage and depth of the lake increased greatly with heavy rains and storm water runoff in the mid-1980s. Following installation of an outlet culvert, lake levels have stabilized. Current surface water area of the basin is 1,231 acres. Maximum depth is 25 feet. Average depth of the lake is estimated at 13 feet. Water transparency has improved over time to average nearly 8 feet during summer months. A trend in increasing water clarity is expected to continue with the discovery of zebra mussels in 2019. Due to 70% of Oscar Lake being less than 15 feet in depth, wind events can temporarily reduce water clarity well below average. Expanses of shallow and clearer water has resulted in Oscar Lake supporting a robust community of submerged aquatic plants, which includes invasive Eurasian watermilfoil. A public access is located on the north shore, just off MN-27. Oscar Lake supports abundant Largemouth Bass, Northern Pike, and panfish populations. Walleyes and Muskellunge are stocked to sustain fishable populations. A standard fisheries survey was completed in August of 2022 to evaluate abundance and size distribution of gamefish populations. Walleye catches were lower than the historical average for Oscar Lake, but the catch rate of 3.8 fish/gill net remains within the range of expected catches for similar lakes in Minnesota. Walleye fingerlings are stocked on alternate years to supplement natural reproduction. Yearling Walleye have occasionally been stocked when fingerling availability was limited. The largest Walleye measured was over 26 inches. Seventy percent of Walleyes exceeded 15 inches. Catch rates of Northern Pike (7.8/gill net) have significantly increased from the previous survey (4.5/gill net). Forty-six percent of pike sampled ranged from 14 to 22 inches in length. In 2022, mean size was almost 23 inches and 2.6 pounds. The largest pike sampled measured 33 inches. Anglers are reminded that new pike zone regulations were implemented in 2018. Oscar Lake is located in the North-central Zone. Anglers can now keep up to 10 pike but not more than two can be over 26 inches in length. All pike between 22-26 inches must be immediately released. Harvesting smaller pike will help shift the population back towards larger individuals and reduce the number of predators for young Walleye and other gamefish. The abundance and diversity of aquatic plants and flooded timber provide great habitat for Largemouth Bass in Oscar Lake. Daytime electrofishing catches were the highest on record, and the catch rate of 61 bass/hour of effort described an abundant population. Bass captures ranged from 6 to 18 inches in total length. Thirty-two percent of the total catch measured 15 inches and larger. Bluegill catch rates averaged 20.3 fish/trap net, which is above average for Oscar Lake. Gill net catch rates of 31.5 Bluegill/net were also higher than average, suggesting fish had moved offshore at the time of the early-August survey. Growth rates are moderate and 7 year old Bluegill averaged almost 8 inches in length. Very few Bluegill over 8 inches were caught during the survey, with the largest fish measuring under 9 inches. Similar to the Bluegill catch, a majority of Black Crappie were captured in offshore gill nets. Black Crappie catch rates of 4.0 fish/gill net were the second lowest over the past two decades. Growth rates are moderate; average length of age 4 fish was over 9 inches. The largest Black Crappie in the sample was over 11 inches and the oldest crappie was 7 years old. Yellow Perch abundance continues to decline, and their sizes are less than desirable for angling. Yellow Perch are an important prey species for the lake's predator population and catch rates of perch have been negatively correlated with Northern Pike catch rates. Other fishes caught during the 2022 survey include Green Sunfish, Hybrid Sunfish, Pumpkinseed, White Sucker, and multiple species of bullheads. Typically, very few Muskellunge are caught during the summer survey. For additional information on the Muskellunge population, a targeted muskie population estimate will be completed during 2024-2025. Oscar Lake was designated as an infested water after the discovery of Eurasian watermilfoil in 1992. More recently, zebra mussels were discovered in 2019. Recreational users should take necessary precautions to prevent further spread of invasive species. Drain all water and remove all aquatic vegetation from your boat and trailer when leaving any body of water.

Based on Minnesota DNR survey data, anglers target Muskellunge, Hybrid Sunfish, Walleye, Largemouth Bass, and Northern Pike in Oscar. See the full species list above for catch rates, size structure, and quality scores.

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

Oscar has a maximum depth of 25 feet and a mean depth of 13 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Oscar is from 2022.

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