Koronis (main lake) Fishing guide

Rice Lake is upstream and connects to Lake Koronis via the North Fork of the Crow River. In the past, Walleye from both Rice and Koronis have spawned in the North Fork of the Crow River upstream of Rice Lake. A Walleye egg take station was operated just upstream of Rice Lake in the Crow River from the 1970's to 1992. However, this Walleye spawning run now appears to be considerably reduced. This is based on anecdotal observations of lower opening Walleye fishing activity near the Koronis inlet bay/narrows area especially since the 2000's and recent (2018-2019) ice out hoop netting in the river near the old egg take station. Walleye fishing activity often was higher during late ice off years at the Koronis inlet bay area due to fish returning from upriver spawning around opening weekend. Walleye also spawn adjacent to the east shores of the three islands in Koronis and the east point of Rice. Since 2001, both Rice and Koronis have been periodic "Spicer Strain" Walleye egg take sites for the statewide Walleye propagation program. Other recent Spicer Strain egg take lakes include Green, Diamond and Elizabeth. Historic spawning sites for Walleye in both Koronis and Rice have been degraded in recent years with increased sedimentation, algal and periphyton growth.

Walleye natural reproduction in Koronis has been frequent and often adequate to sustain Walleye numbers based on previous fall and summer surveys and markings. However, natural reproduction contribution has been more variable in recent years due in part to degraded spawning habitat and unfavorable spring conditions. Walleye fry (0.5-2.0 million/year) were stocked during 1996, 2001-2019 and 2021-2025 as a 10% return of Walleye eggs taken for the DNR statewide Walleye hatching program. No Walleye eggs were taken and no fry were stocked in 2020. Approximately 1.1 million fry were stocked during 2025. It is unknown if Walleye fry stocking into upstream Rice Lake is also contributing to the Koronis population due to downstream movement (drift). Walleye fingerlings were stocked in 2004 (2,409 pounds, 48,180 fish). Various combinations of Walleye ages were stocked in 2006 (2,355 pounds, 45,685 fish) and 2010 (867 pounds, 4,887 fish). Walleye eggs were taken recently in 2021 (155.25 quarts), 2022 (98.75 quarts), 2023 (85.25 quarts), 2024 (91.8 quarts) and 2025 (175 quarts) from Koronis. Stocked Walleye fry were marked with Oxytetracycline "OTC" during 2001, 2007, and 2011-17.

YOY Walleye numbers were abundant (61.00 YOY/hour, 6.86 inches) in the 2025 fall night electrofishing survey. Yearling Walleye numbers were also abundant (77.00 fish/hour, 10.19 inches) in 2025. Two-year-old Walleye were also abundant (10.00 fish/hour, 11.93 inches) in the 2025 fall electrofishing survey. YOY Walleye numbers were abundant (163.00 YOY/hour, 6.15 inches) in 2024. Yearling numbers were abundant (19.00 fish/hour, 9.21 inches) in 2024. YOY Walleye numbers were abundant (120.00 YOY/hour, 7.15 inches) in 2023. Yearling numbers were low (4.50 fish/hour) in 2023. YOY Walleye numbers were moderate (39.00 YOY/hour, 6.55 inches) in the 2022 fall night electrofishing survey. Yearling Walleye numbers were abundant (24.00 fish/hour, 10.40 inches) in the 2022 fall electrofishing survey. We also caught 2.00 fish/hour from the 2020 year class in 2022 fall electrofishing survey. YOY Walleye numbers were abundant (65.00 YOY/hour, 7.23 inches) in 2021 fall electrofishing survey. No Yearling Walleye were observed in 2021. Moderate YOY Walleye numbers (23.16 YOY/hour, 7.62 inches) were captured in 2020 fall electrofishing survey. We also observed moderate numbers of yearling (9.47 fish/hour) and age 2+ (23.16 fish/hour) Walleye in the 2020 survey. Low YOY Walleye numbers were captured in 2019 (1.85 YOY/hour). Abundant yearling Walleye were captured in 2019 (13.85 fish/hour, 9.76 inches). Moderate YOY and yearling Walleye numbers were captured in 2018 (20.57 YOY/hour, 7.20 inches; 8.57 yearlings/hour, 9.71 inches). Abundant YOY Walleye numbers were captured in 2017 (65.60 YOY/hour, 6.03 inches). Oxytetracycline "OTC" marked fish accounted for 33% of the YOY Walleye catch in the 2017 fall. Low numbers of yearling Walleye were captured in 2017 (4.80 fish/hour, 9.90 inches). Low YOY Walleye numbers were captured in 2016 (14.18 YOY/hour, 6.51 inches). OTC marked fish accounted for 40% of the 2016 Fall YOY Walleye catch. Yearling and two year old Walleye numbers were abundant (17.45 fish/hour) in 2016. Low YOY Walleye numbers (3.60 YOY/hour, 5.97 inches) were captured in 2015. There were no OTC marked YOY walleye captured in the 2015 fall electrofishing survey. Yearling Walleye numbers were abundant (22.80 fish/hour, 9.45 inches) in 2015. Abundant numbers of YOY Walleye were captured in 2014 (208.09 YOY/hour, 6.39 inches average length) and 2013 (71.25 YOY/hour, 5.79 inches average length). OTC marked fish accounted for 82% of the 2014 Walleye fingerlings captured in the fall electrofishing survey. Approximately 45% of the 2013 fall electrofishing YOY catch were OTC marked (fry stocked). Moderate YOY Walleye numbers (32.83 YOY/hour, 6.97 inches) were captured in the 2012 fall electrofishing survey. Approximately 92% of the 2012 year class fish captured in the 2012 fall electrofishing survey were OTC marked (fry stocked). Abundant numbers of YOY Walleye (205.50 YOY/hour, 6.50 inches) were captured in the 2011 fall electrofishing survey. Approximately 80% (164.40 YOY/hour) were OTC marked fish in the 2011 fall electrofishing survey. The Koronis YOY Walleye historical average catch rate and average length are 48.89 YOY/hour and 6.67 inches.

Walleye abundance was high in 2024 gillnets (27.00 fish/gillnet) compared to the historical average catch rate (1987-present) of 12.86 fish/gillnet for Koronis. The 2024 Walleye average size was moderate (1.83 pounds and 16.68 inches) from gillnets. The Walleye historical average length is 14.39 inches from gillnets. Approximately 69% of the Walleye captured were 15.00 inches or larger in the 2024 survey nets. Walleye growth rates were within the Spicer Area normal ranges for ages 1-4, but below normal for ages 5-8. The 2021 and 2023 year classes (fry stocked and natural reproduction) comprised 40% and 16% respectively of the 2024 Walleye gillnet and trapnet catch. The largest Walleye captured was 28.74 inches in 2024.

Current fish management activities on Koronis include protecting the important aquatic vegetation such as bulrush through the permit process, participating in local watershed projects, assisting aquatic plant management and enforcement personnel with invasive species monitoring and education, stocking various species as needed, and stocking Walleye fingerlings after two consecutive years of poor natural reproduction as documented by fall night electrofishing surveys. The Koronis fishery will be surveyed annually for YOY Walleye in the fall and 2027 summer for a standard survey.