Big Sandy

Fall night electrofishing (EW) was conducted on 10/02/2025 (representative locations) and 10/06/2025 (standard locations) to monitor natural reproduction, recruitment, and specifically the abundance of young-of-the-year (YOY) and yearling (age 1) Walleye. Eight standard locations have been sampled annually since 2009 in habitats that YOY Walleye likely reside, hereafter called "standard EW". Additionally, an extra EW assessment was conducted for the first time at six locations that represent the variety of habitats in Big Sandy Lake, hereafter called "representative EW". Results from both assessments are compared in this report and will likely continue annually as staff time permits. The total sample time in the standard EW assessment was 2 hours, resulting in a YOY Walleye catch rate of 166.0 per hour (rates reported as run time). Catch rates from previous surveys averaged 87.8 per hour and ranged from 9 to 138 per hour except for 2013, which had an extremely high catch of 490 per hour. Total lengths of YOY Walleye ranged from 3.8 to 7.4 inches and averaged 5.7 inches, similar to previous assessments (2009 - 2024 average length of 5.6 inches). Natural reproduction appears to be higher in years since the regulation was implemented (median YOY catch rate of 20 per hour pre-reg vs 57 per hour post-reg), suggesting a possible benefit of the regulation to Walleye reproduction. The total sample time in the representative EW assessment was also 2 hours and resulted in a YOY Walleye catch rate of 99 per hour. As expected, YOY catch rates in the representative EW were less than the standard EW likely due to differences in YOY habitat selection. However, catch rates in the representative EW were still above the long-term average of the standard EW and may indicate an above average year class in the future. Total lengths in the representative EW ranged from 3.9 to 5.7 inches, with an average of 5.7 and was almost identical to the length indices of the standard EW assessment. The catch rate for yearling Walleye in the standard EW was 40 per hour and was in line with the long-term average of 39 per hour. Whereas the yearling Walleye catch rate in the representative EW was 32 per hour. Walleyes age-2 and greater (age 2+) were also sampled during both assessments. Catch rates for age 2+ Walleye in the standard EW were 25 per hour compared to 31 per hour in the representative EW. Age 2+ Walleye captured in the standard EW measured up to 18.7 inches, with the oldest fish aged being 9 years old. Whereas in the representative EW, Age 2+ Walleye measured up to 19.5 inches, with the oldest fish aged being 7 years old. Fall night electrofishing should continue as staff time permits to continue to evaluate natural reproduction and to determine whether the catch rate of either YOY or age 1 Walleye is a meaningful predictor of recruitment to harvestable size on this lake.

Fall night electrofishing (EW) was conducted on 10/02/2025 (representative locations) and 10/06/2025 (standard locations) to monitor natural reproduction, recruitment, and specifically the abundance of young-of-the-year (YOY) and yearling (age 1) Walleye. Eight standard locations have been sampled annually since 2009 in habitats that YOY Walleye likely reside, hereafter called "standard EW". Additionally, an extra EW assessment was conducted for the first time at six locations that represent the variety of habitats in Big Sandy Lake, hereafter called "representative EW". Results from both assessments are compared in this report and will likely continue annually as staff time permits. The total sample time in the standard EW assessment was 2 hours, resulting in a YOY Walleye catch rate of 166.0 per hour (rates reported as run time). Catch rates from previous surveys averaged 87.8 per hour and ranged from 9 to 138 per hour except for 2013, which had an extremely high catch of 490 per hour. Total lengths of YOY Walleye ranged from 3.8 to 7.4 inches and averaged 5.7 inches, similar to previous assessments (2009 - 2024 average length of 5.6 inches). Natural reproduction appears to be higher in years since the regulation was implemented (median YOY catch rate of 20 per hour pre-reg vs 57 per hour post-reg), suggesting a possible benefit of the regulation to Walleye reproduction. The total sample time in the representative EW assessment was also 2 hours and resulted in a YOY Walleye catch rate of 99 per hour. As expected, YOY catch rates in the representative EW were less than the standard EW likely due to differences in YOY habitat selection. However, catch rates in the representative EW were still above the long-term average of the standard EW and may indicate an above average year class in the future. Total lengths in the representative EW ranged from 3.9 to 5.7 inches, with an average of 5.7 and was almost identical to the length indices of the standard EW assessment. The catch rate for yearling Walleye in the standard EW was 40 per hour and was in line with the long-term average of 39 per hour. Whereas the yearling Walleye catch rate in the representative EW was 32 per hour. Walleyes age-2 and greater (age 2+) were also sampled during both assessments. Catch rates for age 2+ Walleye in the standard EW were 25 per hour compared to 31 per hour in the representative EW. Age 2+ Walleye captured in the standard EW measured up to 18.7 inches, with the oldest fish aged being 9 years old. Whereas in the representative EW, Age 2+ Walleye measured up to 19.5 inches, with the oldest fish aged being 7 years old. Fall night electrofishing should continue as staff time permits to continue to evaluate natural reproduction and to determine whether the catch rate of either YOY or age 1 Walleye is a meaningful predictor of recruitment to harvestable size on this lake.

A temperature - dissolved oxygen (TDO) profile was collected on 7/31/2025 to measure the amount of thermal habitat available for Tullibee in Bill Horn Bay. The TDO3 (temperature at 3 mg/l dissolved oxygen) was determined to be 19.4 degrees C, which is typical of historical profiles. Comparing profiles collected since 2011, the least amount of available Tullibee habitat occurred in 2012, which likely represents a near-worst case scenario given the extreme weather conditions experienced that year. The lake provides "fair" habitat compared to other lakes in the Aitkin management area that are monitored. Because the management area is located near the southern edge of Minnesota's Tullibee range, TDO profiles should continue to be collected to monitor the availability of cold-water habitat.

Based on Minnesota DNR survey data, anglers target Channel Catfish, Muskellunge, Bluegill, Black Crappie, and Rock Bass in Big Sandy. See the full species list above for catch rates, size structure, and quality scores.

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

Big Sandy has a maximum depth of 84 feet and a mean depth of 21.4 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Big Sandy is from 2023.

Yes — Big Sandy has confirmed flowering rush. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.