Maple

A targeted survey of nearshore fish species in Maple Lake was conducted on July 21-22, 2021, 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 10 sampling stations, but three stations were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample three stations, a 15-foot seine was used at two stations, and site conditions prevented the use of seines at five stations. Nearshore sampling captured seven species of fish including one species that is intolerant of disturbance (Rock Bass) and no species that are tolerant of disturbance. The nearshore data were combined with trap net and gill net data from an August 2020 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 (Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (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. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Results from this survey indicate that the fish community in Maple Lake is healthy as indicated by an FIBI score above the impairment threshold for aquatic life use determined for similar lakes. These results will be considered when the biological health of the lake is assessed during the Big Fork River Watershed assessment process, which will be completed in coordination with MN Pollution Control Agency.

Maple Lake is a 228-acre lake in northcentral Itasca County located four miles northwest of Marcell, MN. A state administered public access is located on the south end of the lake off Public Access Road (off Turtle Lake Road (Hwy. 43)). The access has a cement ramp with parking for six rigs. Maple Lake has a maximum depth of 39 ft and 34% of the lake is 15 ft or less. The lake has low fertility. The water color is clear to light green, resulting in visibility to a depth of 18 ft in mid-summer. The depth of water at which oxygen levels limit fish presence was 21 ft in mid-summer. Other area lakes with similar habitat include Cedar, Gunn, Little Bowstring, Little Moose, and Pancake. The 2020 survey was the eighth survey of the fish community since 1973. Surveys occur to monitor for changes in species composition, number, length distribution, and growth. Gamefish species that are best suited for the lake are Walleye, Northern Pike, Black Crappie, and Largemouth Bass. No special regulations are present. The Walleye population had a below average catch rate, an above average length distribution, and below average growth. Gill net catches were the lowest observed (2.3/net). The sampled Walleye ranged from 15 to 23 inches and averaged 19 inches. The length distribution was above average, as 100% of Walleye exceeded 15 inches and 29% exceeded 20 inches. The largest fish ever sampled were 25-inch fish in 2004 and 2012. Walleye ranged from age 5 to 10. Growth rates were below the statewide average. On average, Walleye took five years to exceed 15 inches. Seven of the fourteen Walleye sampled in 2020 were from stocked year classes. The ratio of sampled Walleye from stocked vs. naturally produced year classes in 2020 was similar to past surveys. Overall, more Walleye from non-stocked year classes have been sampled than from stocked year classes. Walleye from stocked year classes have the potential to be naturally produced or stocked. Statewide Walleye stocking guidelines recommend discontinuing stocking if it fails to produce a viable fishery supporting a catch rate of 2.0/gill net. The Northern Pike population had a low to moderate catch rate, with average length distribution and growth. Gill net catches were below average for the lake, and low compared to lakes with similar habitat. Higher catches are undesirable because they are usually associated with higher density populations having poor size structure and slow growth. The sampled pike ranged from 12 to 37 inches and averaged 20 inches. The length distribution was average, as 41% of pike exceeded 21 inches and 3% exceeded 28 inches. However, pike over 34 inches were sampled in three of the last four surveys. The largest fish sampled was a 40-inch fish in 2012. Pike ranged from age 1 to 7. Growth rates were average. On average, pike took four years to exceed 21 inches. The pike population may interest anglers and spearers due to its length distribution. However, due to the lake's small size, anglers are encouraged to release pike over 26 inches and harvest up to 10 less than 22 inches to help maintain and improve size structure. Spearers are encouraged to harvest smaller pike too. Maple Lake is in the North-central Zone for pike management, which may contribute to modest improvements in size quality. The Black Crappie population had average catch rates, above average length distribution, and below average growth. Net catches were average for the lake, but lower than lakes with similar habitat. The sampled crappie ranged from 7 to 14 inches and averaged 9.2 inches. The length distribution was above average, as 73% of crappie exceeded 8 inches and 45% exceeded 10 inches. Ten-inch fish were sampled in the last six consecutive surveys. The largest fish sampled was a 14-inch crappie in 2020. Crappie ranged from age 2 to 9. Six year-classes were sampled. Growth rates were below average. On average, crappie took five years to exceed eight inches. Although the crappie population is lower in number, fish over 10 inches have been consistently sampled and may interest anglers. The Largemouth Bass population had a below average catch rate, average length distribution, and below average growth. Spring nighttime electrofishing targeting bass occurred in 2012 and 2020. This method is the most appropriate way to evaluate a bass population. Electrofishing catches were slightly higher than 2012, but remained lower than the average for Grand Rapids area lakes. The sampled bass ranged from 4 to 17 inches and averaged 12 inches. The length distribution was average, as 53% of bass exceeded 12 inches and 17% exceeded 15 inches. The largest fish ever sampled was a 20-inch fish in 2012. Bass ranged from age 1 to 9. Growth was below average in both electrofishing surveys. On average, bass took five years to exceed 12 inches. Due to the lake's small size, anglers are encouraged to release bass exceeding 15 inches to help maintain or improve size structure. The Bluegill population had a moderate catch rate, with below average length distribution and growth. Trap net catches were similar to average for the lake, but less than lakes with similar habitat. However, higher catches are undesirable because they are usually associated with higher density populations having poor size structure and slow growth. The sampled Bluegill ranged from 3 to 8 inches and averaged 4.5 inches. The length distribution was below average, as only 13% of Bluegill exceeded 6 inches and only 1% exceeded 8 inches. However, Bluegill over 8 inches were sampled in each of the last six surveys, and four 9-inch fish have been sampled. Growth was below average. Bluegill ranged from age 2 to 9. On average, Bluegill took seven years to exceed six inches. Due to the lake's small size, anglers are encouraged to release Bluegill exceeding 8 inches to help maintain or improve size structure. The Yellow Perch population had a low catch rate. The gill net catches were the lowest observed (2.3/net) and declined in each of the last three surveys. Declining perch numbers are consistent with statewide trends that have occurred since the 1970s. Lower perch numbers can limit the number of gamefish the lake can support. The eight perch sampled ranged from 5 to 10.5 inches. Age and growth information has not been evaluated. Statewide Walleye stocking guidelines recommend discontinuing stocking if perch gill net catches fall below 8/net. The Tullibee (Cisco) population had a below average catch rate. The gill net catches were the second lowest observed for the lake, but were higher than lakes with similar habitat. Catch rates have been below average the last three surveys. The sampled Tullibee ranged from 7 to 16 inches. Age and growth information has not been evaluated. Smaller Tullibee provide an important prey source for larger gamefish and can provide predation relief to the perch population. Maple Lake is open to sport netting for Tullibee. Other species sampled included Bowfin (Dogfish), Pumpkinseed Sunfish, Rock Bass, White Sucker, and Yellow Bullhead. In order to maintain or improve fish and wildlife populations, water quality and habitat must be protected. People often associate water quality problems with large-scale agricultural, forestry, urban development or industrial practices in the watershed. In reality, the impact of land use decisions on one lake lot may be relatively small, yet the cumulative impact of those decisions on many lake lots can result in a significant decline in water quality and habitat. For example, removing shoreline and aquatic vegetation, fertilizing lawns, mowing to the water's edge, installing beach sand blankets, failing septic systems and uncontrolled run-off, all contribute excess nutrients and sediment which degrade water quality and habitat. Understanding these cumulative impacts and taking steps to avoid or minimize them will help to insure our quality fisheries can be enjoyed by future generations. Anglers and boaters are reminded to help slow the spread of invasive species by removing all aquatic plants from boats, trailers, and equipment. All drain plugs must be removed and live and bait wells must be drained before leaving the access. Anglers and boaters are encouraged to power wash and thoroughly dry all equipment prior to use in another water body.

Maple Lake is a class 31 lake located in northern Itasca County, north of Marcell, MN. The lake has a concrete public access on the south shore and essentially no shoreline development. The 2005 lake management plan indicates walleye as the primary species of management with bluegill and northern pike as secondary species. The 2012 assessment also included sampling of near shore fish species in order to calculate an Index of Biotic Integrity (IBI) score. Black crappie catch rates have been low in all assessments and have never exceeded the lake class median for gill nets or trap nets. In 2012, 0.4 fish/net were sampled with trap nets while only one black crappie was sampled with gill nets. The trap net sampled fish ranged from 5.1 to 12.2 inches and had a mean length of 9.5 inches. Age and growth information was not collected in this assessment. Trap-net catch rates for bluegill have been near the lake class 1st quartile (6.1 fish/net) in all the assessments. The trap-net catch was 10.3 fish/net in 2012. Bluegill sampled by trap nets ranged from 3.2 to 8.1 inches and had a mean length of 4.8 inches. Bluegills sampled in gill nets were larger than those in trap nets, ranging from 3.4 to 9.3 inches and had a mean length of 6.0 inches. Eight age-classes were identified from scales ranging from age 2 to age 10. Age-2 and age-4 fish represented 66% of the sample. Mean back-calculated lengths-at-age were similar to those reported for class 31 lakes for all ages. Largemouth bass were sampled by spring night electrofishing for the first time in 2012. The catch rate was 24.1 largemouth bass/hr on-time. Largemouth bass ranged from 5.8 to 17.3 inches with a mean length of 10.6 inches. Six year-classes were identified from scales ranging from age 2 to age 9. Growth was similar to the statewide averages for all ages. Northern pike gill-net catch rates have been fairly stable (5.6 to 9.8 fish/net) since 1973. The northern pike gill-net catch was 8.3 in 2012 which exceeded the lake class median of 6.7 fish/net. The sampled fish ranged from 15.4 to 40.4 inches and had a mean length of 20.1 inches. All but one fish were less than 27 inches long. Northern pike were not aged in this assessment. Walleye catch rates have generally been stable ranging from 2.5 to 5.8 since 1973. In 2012, the catch was 4.5 fish/net. The 2012 catch exceeded the management goal of 4.0/net and was near the 3rd quartile value of 5.0 fish/gill net for class 31 lakes. The sampled fish ranged from 9.8 to 26.0 inches and had a mean length of 18.0 inches. Ten year-classes from age 1 to 10 were identified from scales, opercles, and otoliths. Growth was similar to statewide averages for all ages. Walleye averaged 15.8 inches at age 4. Yellow perch gill-net catch rates were the lowest on record. The catch was 1.7 fish/gill net, which is below the lake class 1st quartile value of 3.4 fish/net. The sampled fish ranged from 5.6 to 6.7 inches and had a mean length of 6.0 inches. Age and growth information was not collected. Lower yellow perch numbers may in part be in response to more consistent walleye stocking in the last six years. Tullibee can be difficult to sample with our standard summer sampling gear because they often are suspended over deep water. The tullibee catches have ranged from 3.8 to 12.5 fish/gill net prior to 2012. The catch was the lowest on record at just 0.8 fish/gill net in 2012. The sampled fish ranged from 7.9 to 17.8 inches and had a mean length of 12.5 inches. Other species observed during the population assessment included bowfin, brown bullhead, hybrid sunfish, pumpkinseed sunfish, rock bass, white sucker, and yellow bullhead. Additional species observed during IBI sampling included banded killifish, blackchin shiner, bluntnose minnow, central mudminnow, Iowa darter, mottled sculpin, and tadpole madtom. In order to maintain or improve fish and wildlife populations, water quality and habitat must be protected. People often associate water quality problems with large-scale agricultural, forestry, urban development or industrial practices in the watershed. In reality, the impact of land use decisions on one lake lot may be relatively small, yet the cumulative impact of those decisions on many lake lots can result in a significant decline in water quality and habitat. For example, removing shoreline and aquatic vegetation, fertilizing lawns, mowing to the water's edge, installing beach sand blankets, failing septic systems and uncontrolled run-off, all contribute excess nutrients and sediment which degrade water quality and habitat. Understanding these cumulative impacts and taking steps to avoid or minimize them will help to insure our quality fisheries can be enjoyed by future generations.

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

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

Maple has a maximum depth of 39 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Maple is from 2020.

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