Big

In 2024, a fish survey was completed on Big Lake which included summer gill netting, summer trap netting, and daytime Largemouth Bass Electrofishing. An IBI (Index of Biotic Integrity) survey consisting of Backpack Electrofishing, and 15 foot-wide Siene hauls was also completed. The results and interpretation of IBI data collected in 2024 are provided in a separate report. Largemouth Bass in Big Lake have been relatively consistent in size structure and numbers since 2011, when daytime electrofishing was first introduced. Past daytime catch rates have ranged from 35 to 88 fish per hour with the 2024 catch falling near the middle of that range at 59.2/hour. The 2024 catch rate is considered quite typical for a central Minnesota lake. The average length in 2024 was 11.74 inches compared to a 10.92-inch average of all other surveys. The percent of fish caught over 15 inches was 9% with the largest measuring 18.4 inches. Northern Pike gill net catches continue to demonstrate substantial variation with the 2024 catch rate of 13.5/lift very near the record high of 13.7/lift found in 1999. Catch rates have recently been as low as the 5.3 per lift found in 2016. Northern Pike averaged just 17.2 inches long in 2024 which is smaller than most previous efforts though not unprecedented. Pike longer than 30 inches have been uncommon throughout the lake's gill net history, however a specimen measuring 34.45 inches was captured in 2024 and is the longest fish caught in any survey on Big Lake. Only 13% of pike collected in the gill nets in 2024 surpassed 21 inches providing further indication of a less than optimal size structure. Walleye gill net catches have been within the expected range since 1993 for lake's similar to Big Lake, including the 2024 catch of 1.67/lift. Fingerling stocking took place regularly through 2016 after which fry stocking was practiced. Based on aging information collected in 2024 fry stocking has failed to contribute to the Walleye population. All the Walleyes sampled in 2024 were Age 8 or older. It is apparent that fingerling stocking will be required to sustain the population. Big Lake is currently under a "surplus" stocking status which means it will only receive fingerlings when they are available after higher priority lakes are stocked. Black Crappie catches are often highly variable with low sample sizes typical during summer netting efforts. A total of 75 crappies were sampled when combining trap net, gill net, and electrofishing efforts in 2024. Thirty percent of the combined sample exceeded 9 inches long. The largest fish sampled was 13.4 inches long and was 2 inches longer than any other crappie observed in 2024. Historically, Big Lake's Black Crappie size structure has been dominated by fish under 9 inches and is often impacted by variations in year class strength. Bluegill catch rates in Big Lake are usually high in the summer trap nets. The number of Bluegill trapped in 2024 was the lowest of any survey dating back to 1993. Since the numbers caught in summer trap nets have decreased the size structure has shown improvement. In 1993 there were no documented Bluegills above 7 inches, In the 2016 summer trap net survey there were 38 fish between 7 and 8 inches and 7 Bluegill over 8 inches. The 2024 summer trap net survey showed 66 Bluegill between 7 and 8 inches and 15 over 8 inches, the longest being 8.74 inches, the largest Bluegill ever sampled in Big.

Spring daytime electrofishing was performed May 17, 2019 on Big Lake in an effort to provide data for a potential bass season extension project. The lake has been daytime electrofished during eight springs since 2011. A total of 66 Largemouth Bass were captured in 2019 in 1.5 hours of effort resulting in a catch rate of 44/hour. Bass ranged in length from 2.8 to 17.7 inches in length with 40 of the fish falling in the 12-15.9 inch range. Mean length was 12.2 inches. Past daytime catch rates have been variable ranging from 35 to 88 per hour with a mean of 60 per hour. The 2019 results were typical for Big Lake and suggest a relatively stable population with consistent reproduction. A variety of habitats are present in the lake including bulrush beds, woody cover, lily pads, cattail fringe and boulders. Anglers seeking bass should find a range of sizes with some potential for larger fish over 18 inches. Harvest of bass over 16 inches should be considered carefully as many of these fish may be 10 to 15 years old or even older.

A targeted survey of the nearshore fish community on Big Lake was conducted on July 24, 2017 by Fisheries Lake Index of Biological Integrity (IBI) program staff. Sampling stations were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine. Backpack electrofishing was completed at all ten sites. A 50-foot seine was used to sample eight stations and a 15-foot seine was used at one station. No seine was used at station 2 due to bog fringe with soft substrates, deep water, and dense vegetation. Nearshore sampling captured 16 native species of fish including just one species intolerant of habitat disturbance (Iowa Darter). Data from this targeted nearshore survey is combined with data from a standard gill and trap netting survey in 2016 to calculate a Fish-based Index of Biologic Integrity (FIBI) score that describes the overall health of the lake. 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. 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. The FIBI score for this survey is just above the impairment threshold for aquatic life use determined for similar lakes. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Data from this survey will contribute biological information about the health of the fish community to the Mississippi River-Brainerd Watershed assessment process in coordination with MN Pollution Control Agency.

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

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

Big has a maximum depth of 21 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Big is from 2024.

No invasive species are on record for Big in Minnesota DNR data. Always clean, drain, and dry your equipment to help keep it that way.