Roemhildts

A targeted survey of nearshore fish species in Roemhildts Lake was conducted on July 12, 2022, by DNR Fisheries staff. Ten 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 6 sampling stations, but 3 stations were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample 4 stations, a 15-foot seine was used at 3 stations, and site conditions prevented the use of seines at 3 stations. Nearshore sampling captured 10 species of fish including 2 species that are intolerant of disturbance (Banded Killifish and Iowa Darter) and 1 species that is tolerant of disturbance (Green Sunfish). The nearshore data were combined with trap net and gill net data from a standard 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), while other species are tolerant of degraded conditions (e.g., 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. Data from this survey indicates Roemhildts 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 Cannon River Watershed assessment process in coordination with MN Pollution Control Agency. Minnesota DNR Fisheries Area staff conducted an assessment of lakeshore habitat on Roemhildts Lake on Aug 01 2022, following the Score the Shore survey protocols. The assessment consisted of 21 survey sites evenly spaced 100 meters around the lake. The average lakewide habitat score was 83.3 (+/- 2.9), indicating overall lakeshore habitat quality was moderate (66-84). Approximately 42 percent of the sites were developed with a mean score of 73.5 (+/- 4.6), while undeveloped sites had a mean score of 90.6 (+/- 1.7).

Roemhildts Lake is a small, 71-acre lake located northwest of the town of Elysian in Le Sueur County. Roemhildts Lake has a maximum depth of 60 feet. Roemhildts Lake is one of the least developed lakes in the Waterville area and has generally good water quality and diverse and high-quality habitat. Roemhildts Lake is primarily managed for Black Crappie, Bluegill, Largemouth Bass, and Yellow Perch and secondarily for Northern Pike. Roemhildts Lake is designated as a Tier-2 lake and will be surveyed as part of a regularly scheduled monitoring program at a frequency of every 6 years. A standard survey is used for sampling a wide range of fish species during the summer months using standard methods (i.e., standard time of year, set sampling stations, taking water clarity readings and oxygen/temperature profiles, etc.) and gears (i.e., lake survey gillnets, trap nets, and spring electrofishing for Largemouth Bass). The 2022 survey was completed the week of June 27, 2022, using 3 gill nets, 8 trap nets, and 42 minutes of standard boat electrofishing. Water quality parameters were also measured. A total of 11 Black Crappies were sampled with the gill nets for a catch rate of 3.7/net, indicating low numbers were present. Surprisingly, this was the highest gill net catch rate in seven surveys since 1993. In fact, in three of those surveys no Black Crappies were sampled in the gill nets. The Black Crappies of the 2022 survey ranged from 6.1 to 12.1 inches with an average of 8.7 inches. Five more Black Crappies ranging from 6.3 to 9.3 inches were sampled with the trap nets. Black Crappies from both gears ranged from 1 to 6 years old with 5 year-classes present. Black Crappie growth was moderate with an average length of 8.1 inches at year 3. Historically, Black Crappies have persisted at low densities in Roemhildts Lake. There was no indication from the 2022 survey that will change. A total of 89 Bluegills were sampled with the trap nets for a catch rate of 11.1/net. This was the lowest Bluegill catch rate since 1993. Bluegill catch rates have varied from 11.1/net to 52.1/net with an average of 27.4/net since 1993. Bluegills ranged from 2.5 to 9.5 inches with an average of 6.1 inches. A little over half the sample was over 6 inches and approximately 29% exceeded 8 inches. An additional 10 Bluegills ranging from 6.3 to 8.7 inches were sampled with the gill nets. Bluegills from both gears ranged from 1 to 10 years old with 10 year-classes present. Bluegills aged 3 to 6 were well represented, indicating good consistent recruitment. Growth was slow with an average length of 5.3 inches at year 4. Roemhildts Lake provides excellent habitat for Bluegills and offers a good size structure to anglers, despite slow growth. A total of 101 Largemouth Bass were sampled with standard boat electrofishing for a catch rate of 142.3/hour. Largemouth Bass catch rates have ranged from 14/hour to 142.3/hour with an average of 99.5/hour since 1993. Largemouth Bass ranged from 3.2 to 16.5 inches with an average of 8.5 inches. Largemouth Bass ranged from 1 to 13 years old with 13 year-classes present. Most Largemouth Bass were 2 or 3 years old. Growth was slow with an average length of 7.8 inches at year 3. Northern Pike were the most abundant species in the gill nets. A total of 19 Northern Pike were sampled for a catch rate of 6.3/net, indicating good numbers were present. This was the highest Northern Pike catch rate since 1993. Northern Pike ranged from 13.5 to 30.3 inches with an average of 22.2 inches. Just under 40% of Northern Pike were larger than the legal minimum length limit of 24 inches. The high-quality habitat in Roemhildts Lake supports a consistent, quality Northern Pike population. Other species sampled in 2022 include Bowfin (0.6/trap net), Freshwater Drum (0.3/gill net), Green Sunfish (0.1/trap net), Pumpkinseed (1.1/trap net), Yellow Bullhead (4.8/trap net), Yellow Perch (0.1/trap net), and hybrid sunfish (Lepomis spp.). Anglers can play an important role in maintaining or improving a fish population by practicing selective harvest. Selective harvest allows for the harvest of smaller fish for consumption, while encouraging the release of medium to large fish that may contribute to natural reproduction. This practice helps maintain balance in the fish populations and provides anglers the opportunity to catch more and larger fish in the future. Additionally, smaller fish often taste better and have fewer contaminants than larger, older fish from the same water body. Shoreline property owners also play an important role in the overall health of an aquatic ecosystem, including the fish population. Natural shorelines, including vegetation, woody debris, and bottom substrates, provide valuable habitat for fish and wildlife, help maintain water quality, and reduce bank erosion. Cattails and bulrushes are particularly beneficial for fish spawning, rearing, and feeding. By leaving natural shorelines unaltered or restoring them to natural conditions, shoreline property owners are doing their part to maintain or improve a healthy ecosystem in the lake and protect the resource for future generations. Sky Wigen, fisheries specialist

Introduction Roemhildts Lake is a small, 71 acre lake located in Le Sueur County northwest of Elysian. Roemhildts Lake has a maximum depth of 60 feet and about 44 acres of littoral area. A DNR-maintained public access is located on the northwest corner of the lake. Roemhildts Lake is one of the clearer lakes in the area and has very little residential development. The lake is home to an abundant and diverse aquatic plant community, including northern watermilfoil, water lilies, coontail, and numerous pondweed species, which provide valuable fish habitat. Most of the riparian zone is wooded and intact. Roemhildts Lake is classified in Lake Class 30 based on limnological variables and lake characteristics. Other lakes in this classification include George Lake (Blue Earth County), Steele Lake (Le Sueur County), and Kelly-Dudley Lake (Rice County). Roemhildts Lake is managed primarily for Largemouth Bass, Northern Pike, and Bluegill and secondarily for Black Crappie. No fish stocking takes place in Roemhildts Lake. Roemhildts Lake was surveyed the week of July 5, 2016 by the MN DNR as part of a regularly scheduled monitoring program. This survey included deploying 3 gill nets and 9 trap nets, as well as recording water quality parameters. Since Largemouth Bass are not effectively sampled in nets, electrofishing was conducted on May 16, 2016 to assess the Largemouth Bass population. Roemhildts Lake is scheduled to be surveyed again in 2022. Largemouth Bass Largemouth Bass are unique in that they are not effectively sampled in regular survey gears (gill and trap nets). To sample an index of the population, targeted sampling using an electrofishing boat is required. Electrofishing was conducted on May 16, 2016 to target and assess the Largemouth Bass population in Roemhildts Lake. Given the small size of the lake, the entire shoreline was electrofished. The catch rate was 106.3 fish/hour, which was higher than the long-term average of 88.8 fish/hour. Two fish were also sampled in gill nets (0.7 fish/net). The size structure was generally small, as the lengths ranged from 3.3 to 16.7 inches and averaged 9.3 inches. The woody debris along the shoreline, diverse aquatic vegetation, and relatively clear water in Roemhildts Lake provide ideal Largemouth Bass habitat. The Largemouth Bass population persists through natural reproduction. Spring electrofishing surveys targeting Largemouth Bass will complement each Standard Survey that is completed on Roemhildts Lake (every six years). Northern Pike The Northern Pike gill net catch rate was 4.7 fish/net, which was slightly higher than the long-term average for Roemhildts Lake (3.9 fish/net). Throughout survey history, the Northern Pike population level has remained steady, ranging only from 1.7 to 6.0 fish/gill net since 1981. Northern Pike were also sampled in trap nets, but in low abundance (0.6 fish/net). The lengths of Northern Pike averaged 21.4 inches and ranged from 14.2 to 31.4 inches. Ages ranged from 2 to 7 years old. Most (71%) of the aged fish were age-2. The average length at capture was 17.4 inches at age-2 and 20.0 inches at age-3. Bluegill Bluegills were sampled in trap nets at a rate of 34.2 fish/net, which was lower than the long-term average for Roemhildts Lake (43.5 fish/net). Bluegills were also sampled in gill nets at a rate of 6.0 fish/net. Lengths ranged from 2.9 to 9.3 inches and averaged 6.7 inches. Eighty percent of all Bluegills measured quality length (6.0 inches) or larger. Ages ranged from 1 to 7 years old. The average length at capture was 3.4 inches at age-1, 3.7 inches at age-2, 4.6 inches at age-3, 5.7 inches at age-4, 7.0 inches at age-5, 7.7 inches at age-6, and 7.8 inches at age-7. Numerous year classes were present, which suggested that Bluegill natural reproduction is not limited in Roemhildts Lake. Black Crappie Black Crappie abundance has remained low throughout survey history. The 2016 catch rate was 1.2 fish/trap net, which was below the long-term average for Roemhildts Lake (3.4 fish/net). The lengths of Black Crappies averaged 9.0 inches and ranged from 7.0 to 11.2 inches, which suggested a respectable size structure. Black Crappies ranged from 2 to 6 years old. The average length at capture was 7.4 inches at age-2 and 9.0 inches at age-3. Black Crappies are not stocked in Roemhildts Lake. Other Species Pumpkinseed sunfish were sampled in trap nets at a rate of 3.4 fish/net, which was above the long-term average of 1.2 fish/net. Pumpkinseed lengths averaged 6.7 inches and ranged from 5.3 to 7.4 inches. Hybrid sunfish were sampled in trap nets at a rate of 7.1 fish/net and averaged 7.1 inches. Hybrid sunfish are common in lakes with strong Bluegill and Pumpkinseed populations. A total of 79 Yellow Bullheads were sampled in gill nets (3.0 fish/net) and in trap nets (7.8 fish/net). These fish averaged 12.2 inches. Yellow Bullheads prefer lakes with clearer water, like Roemhildts Lake. Other fish species sampled in low abundance included Yellow Perch, Bowfin, Common Carp, and Brown Bullhead. Angling Summary With its clear water, abundant vegetation, and mostly unaltered shoreline, Roemhildts Lake offers a valuable fishing experience that is getting more difficult to find in southern Minnesota. Largemouth Bass abundance was high at the time of this survey and there was lots of structure to target fish. Bluegill were also worth targeting, as fish 6.0 inches and longer were plentiful. Anglers can play an important role in maintaining or improving a fish population by practicing selective harvest. Selective harvest allows for the harvest of smaller fish for consumption, while encouraging the release of medium to large fish that may contribute to natural reproduction. This practice helps maintain balance in the fish populations and provides anglers the opportunity to catch more and larger fish in the future. Additionally, smaller fish often taste better and have fewer contaminants than larger, older fish from the same water body. Shoreline property owners also play an important role in the overall health of an aquatic ecosystem, including the fish population. Natural shorelines, including vegetation, woody debris, and bottom substrates, provide valuable habitat for fish and wildlife, help maintain water quality, and reduce bank erosion. Cattails and bulrushes are particularly beneficial for fish spawning, rearing, and feeding. By leaving natural shorelines unaltered or restoring them to natural conditions, shoreline property owners are doing their part to maintain or improve a healthy ecosystem in the lake and protect the resource for future generations. -Kip Rounds, Fisheries Specialist

Based on Minnesota DNR survey data, anglers target Largemouth Bass, Northern Pike, Bluegill, Hybrid Sunfish, and Yellow Perch in Roemhildts. See the full species list above for catch rates, size structure, and quality scores.

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

Roemhildts has a maximum depth of 60 feet, per Minnesota DNR data.

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

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