Crystal

Minnesota DNR Fisheries IBI program staff conducted an assessment of lakeshore habitat on Crystal Lake on September 4th, 2025, following the Score the Shore survey protocols. The assessment consisted of 49 survey sites evenly spaced 70 meters around the lake. Assessments were made in three habitat zones: Shoreline Zone (the shore-water interface to the top of the natural bank), Shoreland Zone (land-ward from shoreline to development structure or 100 feet), and Aquatic Zone (lake-ward 50 feet of shoreline). The average lakewide habitat score was 62.5 (+/- 3.7) out of 100 possible. A score of 62.5 indicates the lakewide shoreline condition is Poor (50-65.9). Approximately 78 percent of the sites were developed with a mean score of 53.2 (+/- 3.6) indicating shoreline habitat quality of developed sites is Poor (50-65.9), while undeveloped sites had a mean score of 94.5 (+/- 1.8) with Excellent (92+) habitat quality.

A targeted survey of the nearshore fish community in Crystal Lake was conducted by Fisheries Index of Biological Integrity (IBI) Program Staff from 7-9 August 2023. Ten sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 15-foot or 50-foot seine, where possible. Backpack electrofishing was completed at all 10 sites with two sites sampled from the boat. A 50-foot seine was used to sample seven sites and soft sediments with abundant vegetation and deep water prevented the use of seines at three sampling sites. Nearshore sampling captured 11 native species of fish including two species that are tolerant of disturbance (Black Bullhead and Green Sunfish). A concurrent summer trap net survey was conducted on 7-9 August 2023 by IBI Program Staff. Twelve trap nets were set along the shoreline that encompassed multiple habitat types. Bluegill and Pumpkinseed comprised a majority of the trap net catch by number and Bluegill and Tiger Muskellunge comprised a majority of the catch by biomass. The number of Bluegill sampled per net was about the 50% quartile for similar Lake Class 34 lakes and the average length was 5.5 inches, with 5% over 7 inches. The number of Black Crappie sampled per net was also about the 50% quartile for Lake Class 34 lakes and the average length was 8.0 inches with 8% (2 out of 24) over 10 inches. The nearshore and trap net data were combined with gill net data from a July 2023 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., Blackchin Shiner, Iowa Darter, and Rock Bass), 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 Crystal Lake in in summer 2023 resulting in a 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 Crystal 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 Lower Minnesota River Watershed assessment process in coordination with MN Pollution Control Agency.

Crystal Lake is a class 34 lake located in Dakota County with a surface area of 288 acres. The lake has a maximum depth of 37 feet and mean depth of 10 feet. The fishery is primarily managed for Tiger (Hybrid) Muskellunge and Largemouth Bass with Walleye as a secondary management species. Tiger Muskellunge are stocked at a rate of 1.5 fingerlings per acre every other year. Walleye are stocked, when surplus fingerlings are available, at a rate of 0.65 pounds per littoral acre. They were first stocked in 2018 and this survey as well as the previous survey conducted in 2021 were conducted with gill nets primarily to assess the success of recent stocking. Trap nets were also set to sample near-shore fish in order to inform an Index of Biological Integrity (IBI) survey. Walleye were sampled at a rate of 1.75 fish per gill net. This is below average for the lake class and slightly lower than the previous catch rate of 2.2 fish per gill net. Of the seven fish sampled, six were 4 years old and one was 1 year old. Those 4 year old fish ranged from 16 to 20 inches long indicating good growth but perhaps low recruitment to the fishery from stocking. Northern Pike were sampled at a rate of 2.5 fish per gill net. This is lower than average for the lake class but similar to the last couple of surveys. Size appears to be improving over the last couple of decades with fish sampled during this survey averaging 26 inches in length and ranging up to 36.7 inches long. Mean size substantially exceeds the 75th percentile for the lake class. Yellow Perch were sampled by gill nets at a rate of 4.75 fish per net. This is low relative to the lake class but typical considering the history of the lake. Size was unimpressive with a mean length of six inches and no fish exceeding 10 inches. Black Crappie were sampled by trap nets at a rate of 1.5 fish per net. This much lower than average for the lake class but similar to historical catch rates. Fish ranged from 4.2 to 10.2 inches and averaged 7.9 inches in length. Slightly larger fish were sampled by gill net with the largest individual measuring 12.2 inches. Bluegill were sampled at a rate of 30.25 fish per trap net. This is higher than average for the lake class but typical relative to the fairly high variability of catch rates in previous surveys. Fish size was unremarkable with a range of 3.2 to 7.5 inches and a mean length of 6 inches. While not a target of this study due to unreliable sampling of them by these methods, four Tiger Musky were captured. Three were fairly small at about 15 inches in length and one measured 33.7 inches. Other species sampled included: Black Bullhead, Golden Shiner, Green Sunfish, Hybrid Sunfish, Largemouth Bass, Pumpkinseed, and Yellow Bullhead

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

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

Crystal has a maximum depth of 37 feet and a mean depth of 9 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Crystal is from 2023.

Yes — Crystal has confirmed Eurasian watermilfoil. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.