Holy Water

A targeted survey of nearshore fish species in Holy Water Lake was conducted on July 24, 2025, by Aitkin Area fisheries staff. Sampling sites (N=10) 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, one of which was sampled via boat due to soft sediment. Similarly, a 50-foot seine was used to sample 3 stations, and a 15-foot seine was used at 6 stations. One station was not seined due to soft sediment. Nearshore sampling captured 9 species of fish including 2 that are intolerant of disturbance (e.g., Blacknose Shiner and Iowa Darter) and zero species that are tolerant of disturbance. The nearshore data were combined with trap net and gill net data from a 6/23/2025 standard survey to describe the fish community and provide a fish-based score of biotic integrity (FIBI). The FIBI score uses fish community data to quantify a lake's health, and the types of fish species present can help identify 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, Rock Bass), while other species are tolerant of degraded conditions (e.g., Green Sunfish, Common Carp). 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 web site. Results from this survey provide evidence that the fish community in Holy Water Lake is healthy as indicated by an FIBI score above the general use impairment threshold for aquatic life use determined for similar lakes. These results are similar to previous findings which indicated that Holy Water Lake is fully supporting aquatic life. These survey results will be considered when the biological health of the lake is assessed during the Mississippi River-Grand Rapids watershed assessment process, which will be completed in coordination with MN Pollution Control Agency. You can help protect the fish community in Holy Water Lake by preventing the spread of invasive species, exhibiting safe forestry practices, and minimizing environmental impacts when visiting the state forest.

Holy Water Lake is located in the northwest corner of Aitkin County, approximately 7 miles west of Hill City. The lake is 77 acres in size and has a maximum depth of 56 feet. The lake is surrounded by county land and although there is no designated public access on the lake, access for small boats or canoes can be gained through a county forest road on the east side of the lake. A standard survey was conducted to assess the fish assemblage during the week of 6/23/2025. An electrofishing survey to assess the Walleye spawning stock was also performed on 4/30/2025. It is thought that the now well-established Bluegill population was introduced to the lake by anglers sometime in the mid-1990's. The species was first documented in 2005, during a routine assessment and was captured at an extremely high rate of 180.5 per trap net. After reaching an all-time high of 238.5 per net during the 2015 survey, relative abundance has declined. Bluegill were sampled at a rate of 26.3 per trap net during the 2025 survey, likely due to the successful introduction of Walleye via stocking efforts. While abundance of Bluegill has decreased, and the numbers of smaller fish have declined , size structure remains small overall. Bluegill captured in trap nets averaged 5.3 inches and ranged in length from 2.8 to 9.9 inches. While growth rates are still rather slow, they do appear to be improving. In addition to Bluegill, Hybrid Sunfish (Bluegill x Pumpkinseed) were also observed and contributed to the Sunfish population over 7 inches. Walleye have been stocked as fingerlings every other year in Holy Water Lake since 2014 as an effort to provide an additional fishery and reduce abundance of small Bluegills. In 2025, Walleye were captured at a rate of 3.7 per gill net, matching the catch rate of the 2020 survey. This catch rate was above average for the lake class (0.50 per net) and above goals of the management plan (0.8/net with improvements to Bluegill or 3/net without). Gill net-captured Walleye ranged in length from 15.0 to 21.9 inches in length, with an average of 18.1 inches and exhibited good growth, exceeding 14 inches in 3 years. During the spring spawning stock assessment, Walleye were captured by electrofishing at a rate of 89.6 per hour. Fish ranged from 5.5 to 26.5 inches in length, with an average of 17.7 inches. Refer to the "4/30/2025 Targeted Survey" in LakeFinder for more detailed results of the spawning stock assessment. Northern Pike relative abundance was stable at 6.0 per gill net. This catch rate falls within the normal range for this type of lake. Captured Northern Pike ranged in length from 20.4 to 26.5 inches, with an average of 22.7 inches. Only one Northern Pike greater than 26.0 inches was observed during sampling. Growth rates appear to be good for the Aitkin Area, exceeding 21 inches in 4 years. With noticeable improvements in this fishery since the inception of Walleye stocking, anglers are asked to practice selective harvest by releasing larger pike, smaller Walleye, and larger Bluegills. In addition to the standard survey work, IBI (Index of Biotic Integrity) sampling using backpack electrofishing and seining was also conducted in 2025 (Targeted Survey 07/24/2025) to more broadly sample the general fish community and develop a fish-based index of overall lake health. Nine nearshore fish species were sampled during the IBI survey including Bluegill, Bluntnose Minnow, Central Mudminnow, Golden Shiner, Hybrid Sunfish, Iowa Darter, Tadpole Madtom, White Sucker, and Yellow Perch.

Spring Walleye electrofishing was conducted on Holy Water Lake the night of 4/30/2025 to monitor the adult Walleye population. The entire shoreline was sampled with 2 netters for a total run time of 1.25 hours. Water temperature was 51.2 degrees Fahrenheit. Walleye length, sex, and spawning condition were recorded. A total of 112 Walleye were sampled, resulting in a catch rate of 89.6 per hour. Fish ranged from 5.5 to 26.5 inches and averaged 17.7 inches. Eighty-eight percent (n = 98) of the catch were males, 8 percent (n = 9) were female, and 4 percent were unknown. Males ranged from 14.6 to 21.6 inches and averaged 17.5 inches. Females ranged from 15.3 to 26.5 inches and averaged 20.3 inches. Five of nine (56 percent) females were spent, 1 was green, 2 were immature, and 1 was unknown spawning condition. Eighty-five percent (n = 83) of males were ripe, while 15 percent (n = 15) were spent. With warm water and such low numbers of females that were mostly spent, it appears that we sampled the end of the spawning run on Holy Water Lake. Other species observed during the assessment include numerous small Yellow Perch, moderate numbers of quality Bluegill, large White Suckers, and a few Northern Pike estimated to be around 20 to 25 inches.

Based on Minnesota DNR survey data, anglers target Walleye, Hybrid Sunfish, Northern Pike, Bluegill, and Pumpkinseed in Holy Water. 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 Holy Water. Check the DNR LakeFinder page for current access details before you go.

Holy Water has a maximum depth of 56 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Holy Water is from 2025.

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