Roy

A targeted survey of nearshore fish species in Roy Lake, which lies within the boundaries of the White Earth Reservation, was conducted on July 17-18, 2023 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 seine, where possible. Backpack electrofishing was completed at all 14 sampling stations, but four stations were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample eight stations, a 15-foot seine was used to sample two stations, and site conditions prevented the use of seines at four stations. Nearshore sampling captured 13 species of fish including two species that are intolerant of disturbance (i.e., Blackchin Shiner and Iowa Darter) and one species that is tolerant of disturbance (i.e., Green Sunfish). The nearshore data was combined with gill net and trap net data from a July 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., Blackchin Shiner, Iowa Darter, and Rock Bass), 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.

Roy Lake (also known as Simon Lake) is 689-acres with a maximum depth of 16 feet. It is located along the border between Mahnomen and Clearwater counties and within the White Earth Indian Reservation. Dense beds of submersed aquatic vegetation are present throughout much of the lake. Roy Lake has experienced infrequent winterkills in the past, with moderate winterkills occurring in 1996 and during the winter of 2017-2018. There is a tribal-owned public access on the northwest corner of the lake. A standard fisheries survey was conducted in mid July 2022 to evaluate the fish populations at Roy Lake. Walleye catch rate in 2022 was 4.7 fish per net, a slight increase from the 4.2 per net observed in 2017. The historical average catch rate is 8.5 Walleye per net. Walleyes sampled in 2022 averaged 16.2 inches with the longest fish only being 17.1 inches. However, 52% of the Walleyes sampled were over 15 inches. The Northern Pike gill net catch rate in 2022 was 16.3 per net, which was higher than Roy Lake's historical average of 9.7 fish per net. The average length of Northern Pike in 2022 was 23.3 inches and lengths ranged from 16.5 to 32.8 inches. Fish 24 inches or large made up 39% of the sample. Bluegill trap net catch rates remained well above the expected range and reached a historical high in 2022. The average Bluegill sampled was 6.2 inches, with the longest one being 7.2 inches. Bluegill growth appears to be stunted as very few fish grow past seven inches. Black Crappie have historically been sampled in low abundance, but the 2022 survey sampled them above the state average catching 8.1 per net. Black Crappie caught in trap nets were sampled up to 11.1 inches in length and averaged 8.2 inches. Largemouth Bass were sampled in moderate numbers in 2022. Largemouth Bass lengths ranged from 5.2 to 17.1 inches. Largemouth Bass averaged about 13 inches in length. The Yellow Perch catch rate remained below the lakes historical average of 15.3 fish per net. In 2022, 5.5 fish per gill net were captured. The mean length was 7.7 inches and sampled Yellow Perch measured up to 9.1 inches. The increase in Northern Pike abundance is likely keeping Yellow Perch numbers in low abundance. Other sampled fish species included Brown and Yellow Bullhead, Common Carp, Pumpkinseed, and White Sucker.

Roy Lake is a 689-acre, class 39 lake with 16 foot maximum depth, located along the border between Mahnomen and Clearwater counties and within the White Earth Reservation. Dense beds of submersed aquatic vegetation are present throughout much of the lake. Roy Lake has experienced infrequent winterkills in the past. Most recently, a moderate winterkill occurred in 1996. Oxygen levels became very low again in 2001 but the lake did not winterkill. An extended winter in 2017-2018 will likely result in some extent of winterkill, but full assessments of the extent of the winterkill will not occur until after this study is published. Despite Walleye fingerling stocking in odd years, the Walleye catch rate in 2017 was only 4.2 fish per net, which was one the second lowest rates observed since surveys began. The historical mean catch rate is 8.5 Walleye per net. Walleyes sampled in 2017 averaged 16.1 inches and 1.6 pounds. The Northern Pike gill net catch rate in 2017 was 13.0 per net, which was higher than Roy Lake's historical mean of 9.0 fish per net. The mean length was 23.9 inches and lengths ranged from 16.2 to 32.2 inches. On average, Northern Pike grew to 23.5 inches in four years. The Yellow Perch catch rate rebounded from the new low set in 2012 to 10.4 fish per net in 2017, but still remained below the historical average of 15.3 fish per net. The large decrease in perch abundance can likely be attributed to the sharp, recent increase in pike abundance. Black Crappie relative abundance as indexed by trap nets has historically been quite low, with the exception of 2007. Trap net caught Black Crappie ranged 4.4 to 9.7 inches in length and averaged 8.3 inches. Bluegill trap net catch rates remained well above the expected range. The 2017 catch rate was 51.6 fish per net, also well above the lake's historical average of 34.8. This historical average is heavily effected by very low catches during the first three surveys of Roy Lake. Lengths of sampled Bluegills ranged from 3.2 to 7.7 inches with a mean of 5.2 inches. Abundant gill net catch rates (6.2 per set) and moderate trap net catch rates (2.5 per net) were found for Largemouth Bass in 2017. Bass lengths ranged from 5.9 to 18.1 inches. Bass averaged 13.6 and 10.4 inches in length in gill net and trap nets, respectively. Other sampled fish species included Common Carp, Pumpkinseed Sunfish, White Sucker, and Yellow, and Brown Bullhead. Black Bullheads were not sampled in 2017.

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

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

Roy has a maximum depth of 16 feet, per Minnesota DNR data.

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

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