Shallow

A targeted survey of nearshore fish species in Shallow Lake was conducted beginning on June 24th, 2024 by Index of Biological Integrity (IBI) Program 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 14 sampling stations. Similarly, a 50-foot seine was used to sample 11 stations, a 15-foot seine was used at two stations, and site conditions prevented the use of a seine at one station. Nearshore sampling captured 16 species of fish including six species that are intolerant of disturbance (i.e., Banded Killifish, Blackchin Shiner, Iowa Darter, Least Darter, Mottled Sculpin, and Rock Bass) and no species that are tolerant of disturbance. 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., Banded Killifish, Least Darter, and Mottled Sculpin), while other species are tolerant of degraded conditions (e.g., Black Bullhead, Fathead Minnow, and Green Sunfish). 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. An additional survey was completed on Shallow Lake in June 2014 resulting in a lower, but similar FIBI score. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Data from this survey indicates Shallow Lake is healthy as indicated by an exceptionally high FIBI score, well above the impairment threshold for aquatic life use determined for similar lakes. These results are similar to previous findings which indicated that Shallow Lake is fully supporting aquatic life. 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.

Shallow Lake is in the Mississippi River Watershed southwest of Warba. Shallow Lake has a total surface area of 531 acres, a littoral area of 268 acres (50% of the lake is less than 15 feet deep), and a maximum depth of 85 feet. The lake has one unnamed inlet and an outlet through a bog that leads to the Swan River. The lake is characterized by a steep sided, deep basin on the western side and a shallow flat side with emergent plants on the eastern end. Previous surveys have identified a diverse aquatic plant community. Residential development is relatively high around most of the lake. The lake management plan was last revised in 2015 when Northern Pike and Walleye were the primary management species. The goals of the plan were to maintain the Walleye gill net catch at 3.0 fish/gill net and maintain a quality Northern Pike population characterized by a catch of less than 3.0 fish/gill net with 25% exceeding 28 inches. Shallow Lake was stocked with Walleye fingerlings at a rate of two pounds per littoral acre (acres less than 15 feet deep) every other year from 2004- 2015 to improve the Walleye gill net catch rate. This was a higher than typical stocking rate for lakes in the Grand Rapids Fisheries Area and appeared to contribute to marginally higher catch rates, but Walleye growth was slow. The stocking rate was adjusted beginning in 2016 when one pound of fingerlings per littoral acre were stocked annually with hopes of improving growth rates by reducing competition between young Walleye. A standard survey was conducted on Shallow Lake in June of 2022 consisting of 9 gill nets and 9 trap nets. The purpose of the survey was to determine the status of the fish community and continue to evaluate the effectiveness of Walleye fingerling stocking. Electrofishing for Largemouth Bass was not completed in 2022 due to staffing and workload considerations. Shallow Lake has a history of low to moderate gill net catches of Walleye and the population is maintained by stocking. It should be noted that lakes with similar habitats typically do not produce large Walleye catches. The 2022 gill net catch rate was typical for lakes with similar habitats, average for Shallow Lake, and near the management goal. Walleye lengths from the gill nets ranged from 9.1 to 27.6 inches and averaged 18.3 inches. Recent recruitment appeared to be poor as age estimates ranged from age-4 to 21 suggesting average year-class production from 2016-2018 but poor survival from 2019-2021. Growth was faster than the previous survey and was near the statewide average as Walleye averaged 14.6 inches by age 4. Older fish appeared to grow slowly, however. Several fish exceeding age-10 were observed suggesting low harvest rates and good adult survival. It continues to appear that stocking can maintain a fair Walleye fishery, but a larger population is unsustainable due to poor recruitments caused by competition from other predators, limited prey, and overall habitat conditions. Northern Pike have occurred in low numbers with a quality size structure. Average size and growth are typically good when Northern Pike occur at low densities so relatively low pike numbers are a desirable attribute of Shallow Lake. The 2022 catch rate was typical for similar lakes but the highest observed for Shallow Lake. The fishery continued to produce an excellent size structure. Northern Pike ranged from 15 to 43.3 inches and averaged 27.6 inches. Thirty-three percent of sampled pike exceeded 28 inches, exceeding the management goal. Growth was fast and resembled past surveys. Pike averaged 28 inches by age-6. Age distribution was balanced with fish up to age-10 and 47% were age-6 or older suggesting low adult mortality. Releasing medium and large pike is the best way to maintain a quality Pike population and avoid the problem of too many small pike. Anglers are encouraged to help maintain the quality pike population in Shallow Lake by limiting harvest to pike under 22 inches. Black Crappie populations often exhibit irregular recruitment resulting in dominant year-classes, shifting age and size structures, and inconsistent angler success. Shallow Lake has a history of sporadically producing a quality Black Crappie fishery. The gill net catch in 2022 was high compared to similar lakes and above the long-term average for Shallow Lake. Gill net caught crappie ranged from 4.5 to 13.2 inches and averaged 9 inches with 36% of the gill net sampled crappie exceeding 10 inches. Growth resembled past surveys and was fast. Crappie averaged over 10 inches by age 5. Recruitment appeared to occur frequently and ages-2 to 10 were present. Year-class strength varied and 45% of the sampled fish were from the 2019 year-class. The catch rate and size structure suggested good angling opportunities. Lakes with similar habitats often produce high numbers of slow growing sunfish. Bluegill catches from Shallow Lake were high in most surveys and relatively few fish exceeded 8 inches. The 2022 catch was typical for the lake class but below average for Shallow Lake. Size structure has been poor but improved dramatically in 2022 when Bluegill from the trap nets ranged from 3.1 to 9.2 inches and averaged 6.5 inches and 10% exceeded 8 inches. The improved size quality followed a record low catch in 2014 suggesting an improvement in growth rates. Growth rates were described as slow in the 1992 survey but improved in 2022 when they were faster than typical for the lake class. Bluegill averaged 6.1 inches by age-6, but only averaged 7.3 inches by age-8. Despite the improvement, growth was still too slow to consistently produce a high-quality fishery. Higher quality Bluegill fisheries typically support low to moderate numbers and produce 8-inch fish in 8 years or less. Ten year-classes were present, and recruitment appeared consistent. Fish up to age-11 were sampled suggesting relatively low adult mortality. Good angling opportunities for high angler catch rates of moderately sized Bluegill should exist given the overall abundance and size structure. Bluegill over 8 inches may take a decade or more to produce so anglers are encouraged to release larger fish to help maintain the improved size quality. Largemouth Bass have been commonly sampled from Shallow Lake. Bass were sampled at a catch rate which is typical for the lake class. Bass ranged from 12.5 to 16.4 inches and averaged 14.7 inches. It should be noted that Largemouth Bass are difficult to sample in standard survey nets. Spring electrofishing was not conducted in 2022, but sampling in 2009 indicated relatively high bass abundance with a population dominated by small fish. Cisco (Tullibee) are important prey that contribute to the production of large predators such as Northern Pike and Walleye. Cisco were not sampled from Shallow Lake prior to the 1970's but catches were moderate over the last several decades. The 2022 Shallow Lake catch was typical compared to similar lakes, but below average for Shallow and the lowest observed since 1981. Captured Cisco were generally large, ranging from 11.6 to 18.5 inches with an average length of 13.9 inches. Shallow Lake has been closed to sports netting for Cisco, but residents indicate that ice angling for this species has increased in popularity. Yellow Perch are important prey for Walleye and low numbers may limit the Walleye population. Lakes that resemble Shallow Lake typically produce low to moderate catches of Yellow Perch. The 2022 catch was typical for similar lakes and near the long-term average for Shallow Lake. Size structure was moderate as perch ranged from 5.7 to 10.6 inches with an average length of 7.1 inches. Small size and relatively low numbers likely limit the popularity of the perch fishery, but they appeared to exist in sufficient numbers to support the existing predatory fish populations. Other species captured included Pumpkinseed Sunfish, Hybrid Sunfish, Rock Bass, White Sucker, and Yellow Bullhead. Anglers and boaters are reminded to drain all water from boats and bait containers, remove all vegetation from boats and trailers, and are encouraged to wash and thoroughly dry all equipment prior to use in another waterbody.

Index of biological integrity data was collected in 2014 in conjunction with Minnesota Pollution Control Agency watershed sampling.

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

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

Shallow has a maximum depth of 85 feet, per Minnesota DNR data.

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

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