Rat

A targeted survey of nearshore fish species in Rat Lake was conducted on July 8, 2022 by Aitkin Area Fisheries Staff. Sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack electrofishing was completed at all ten sampling stations, but three stations were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample four stations, a 15-foot seine was used at two stations, and site conditions prevented the use of seines at four stations. Nearshore sampling captured 8 species of fish. The nearshore data were combined with trap net and gill net data from a June 2022 survey to describe the fish community and provide a Fish-based IBI (FIBI) score. 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. In Minnesota lakes, certain fish species cannot survive without clean water and a healthy habitat (e.g., Iowa Darter and Rock Bass), while other species are tolerant of degraded conditions (e.g., Green Sunfish and Black Bullhead). 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. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Data from this survey indicates the fish community of Rat Lake is in good health as indicated by an FIBI score above the impairment threshold for aquatic life use determined for similar lakes. Data from this survey will contribute biological information about the health of the fish community to the Mississippi River-Grand Rapids Watershed assessment process in coordination with MN Pollution Control Agency.

Rat Lake is located in east central Aitkin County and is part of the Big Sandy Lake watershed. There is a state-owned public access with a concrete ramp on the south side of the lake. Like many of the lakes in the Big Sandy watershed the water is bog stained. Rat Lake has a history of occasional winterkill with the last known occurring in the 1980s. Rat Lake is primarily managed for Bluegill and Secondarily for Walleye and Black Crappie. This lake is part of the Quality Sunfish Initiative (QSI) where the limit is 10 sunfish per day. Historically, the biggest concern for Rat Lake was a steady decline of the Yellow Perch population starting in 1987, and the subsequent decline in growth rates for Bluegill and Black Crappie. Predation from Walleye on the young perch, coupled with predation from Northern Pike on adults may have been enough to reduce Perch abundance, which can negatively affect the growth rates of other species in the lake. Rebuilding the perch population is key to maintaining a healthy fish community in Rat Lake. To correct that trend, Walleye fry stocking was suspended in 2008, to decrease predation on perch. Per management plan guidelines, Walleye stocking resumed in 2012, at a reduced fry density. As a result, it appears perch catch rates improved from 2007 to 2011 and have remained stable since. Walleye numbers are still below our goals for this lake (0.8/gill net vs 3/gill net goal). In some years, Walleye movement from the Sandy River system can be equally important to stocking in Rat Lake. There also appears to have been improvements in population characteristics for both Bluegill and Black Crappie, resulting in an improvement in size structure for these populations. An earlier trend of higher Bluegill abundance reversed itself by 2017, resulting in a catch rate of 3.8/trap net compared to much higher catches in the previous three surveys. Catches did increase somewhat in 2022 to 12.9/trap net, but are still within management guidelines for the lake. Size structure also appeared to improve with 37% over eight inches in length, compared to an average of 4% from 2002 through 2011. Bluegill over 9 inches were also observed. Rat Lake is well known in the McGregor area for its winter Black Crappie fishery. Like many Black Crappie fisheries, it can be quite variable and occasional strong year classes influence their abundance and the fishery. The size structure has also showed some improvements over time with fish over 12 inches observed in each of the last two surveys. In addition to adjustments in stocking and frequency of winterkills, anglers can affect changes of their own by practicing selective harvest of the quality panfish in Rat Lake. Large Bluegills are a special resource and can have tremendous influence in their population.

A survey targeting Bluegill was completed on 6/08/2020 to aid in the evaluation of upcoming special regulations set forth by the MN DNR's Quality Sunfish Initiative (QSI). This data is pre-regulation and will help provide a baseline to determine if a 10 fish bag limit (implementation 2021) is having any effect on the fishery. Four daytime electrofishing runs were completed for a total of 0.9 hours of sampling effort. The catch rate for Bluegill was 115.5 per hour with 1 netter. Bluegill sampled ranged from 4.7 inches to 9.0 inches with an average size of 7.3 inches. Eighteen Bluegill larger than 8 inches were sampled. Future spring surveys and standard survey data will be used to evaluate the regulation.

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

We don't have a confirmed public access point on record for Rat. Check the DNR LakeFinder page for current access details before you go.

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

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

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