Gervais

A targeted survey of nearshore and littoral fish species in Gervais Lake was conducted beginning on September 7th, 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. Similarly, a 50-foot seine was used to sample nine stations, and site conditions (soft sediment and deep water) prevented the use of seines at one station. Nearshore sampling captured 15 species of fish including no species that are intolerant of disturbance and three that is species that are tolerant of disturbance (Black Bullhead, Common Carp, Green Sunfish). A concurrent summer trap net survey was conducted the week of September 7th, 2021 by IBI Program Staff. Nine trap nets were set along the shoreline and in shallow offshore locations that encompassed multiple habitat types. Bluegill comprised a majority of the trap net catch by number and Bluegill and Common Carp accounted for the majority of the biomass. Bluegill count per net was between the 25th and 50th quartile, while the Bluegill mean weight was just below the 25th quartile for similar Lake Class 24 lakes. The nearshore and trap net data were combined with gill net data from a July 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 (e.g. Banded Killifish, Blackchin Shiner, and Rock Bass), while other species are tolerant of degraded conditions (e.g. Green Sunfish, Black Bullhead, and 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 website. Data from this survey will contribute biological information about the health of the fish community to the Mississippi River-Twin Cities Watershed assessment process in coordination with MN Pollution Control Agency.

Gervais Lake is categorized as lake class 24 with a surface area of 235 acres, with 91 acres being littoral (38.7%). The lake has a maximum depth of 41.0 feet. The lake has variable, but fair water clarity with a maximum secchi disk reading during this survey of 3.5 feet, which is lower than the long-term average on this lake. Ramsey County operates a small park on the southwest corner of the lake which contains a picnic area, a swimming beach, and a fishing pier. Boats gain access to this lake from a channel in adjacent Spoon Lake, and frequently use the park area as a starting point for water skiing and other recreational activities. The water is deemed suitable for swimming and wading, with decent clarity and low algae levels with moderate turbidity throughout the open water season. Gervais Lake is primarily managed for Walleye and Hybrid Muskellunge (Tiger Muskellunge). Walleye management was changed in 2017 to stocking 0.65 pounds of fingerlings per littoral-acre on an annual basis (59 pounds). The previous stocking regime since 1994 consisted of stocking fingerlings biennially, in even numbered years, at a rate of 2.0 pounds per littoral acre (182 pounds). The stocking of Tiger Muskellunge was initiated in 1985 with the stocking of 125 fingerlings. Current Tiger Muskellunge stocking is conducted biennially, on odd numbered years, at a rate of 1.0 fingerlings per surface acre (235 fish). Gervais Lake is also stocked with surplus Tiger Muskellunge fry in years they are available. Concentrations of PFOS and mercury in fish tissue from Gervais exceed the water quality standard, and a fish consumption advisory has been issued for this lake for Bluegill, Black Crappie and Walleye. Monitoring contaminants in fish from Gervais Lake will be ongoing. The 2020 Walleye catch rate on Gervais Lake was 4 per gill net, the third highest observed in Gervais Lake (See Table 1). The average size of Walleye in the gill nets was 14.89 inches and sampled fish ranged in age from 1 to 6 years old. The 2020 Northern Pike catch rate abundance (15.8 fish per gill net) was the highest on record for Gervais Lake. High numbers of Northern Pike can reduce the success of Walleye and Tiger Muskellunge stocking due to predation. The average size pike in 2020 was 25 inches long. Gervais Lake is in the North-Central Zone for Northern Pike management which allows a harvest of 10 fish, with 2 allowed over 26 inches, and a protected slot between 22 and 26 inches. The objectives of this regulation is to see some modest improvement in northern pike size distribution, reduce densities of small pike, and improve harvest opportunity for smaller and preferred size pike.

Gervais Lake is categorized as lake class 24 with a surface area of 235 acres; with 91 acres being littoral (38.7%). The lake has a maximum depth of 41.0 feet. The lake has variable, but fair water clarity with a maximum secchi disk reading during this survey of 4.0 feet which is lower than the long-term average on this lake. Gervais Lake is primarily managed for Walleye and hybrid Muskellunge. Recent management activities have consisted of the regular stocking of those two species. Walleye management was changed in 2017 to stocking 0.65 pounds of fingerlings per littoral-acre on an annual basis (59 pounds). The previous stocking regime since 1994 consisted of stocking fingerlings biennially, in even numbered years, at a rate of 2.0 pounds per littoral acre (182 pounds). Although Walleye were captured in netting assessments in this lake prior to initiation of stocking, it is likely that they migrated here from previous stockings in Phalen Lake. The stocking of hybrid Muskellunge was initiated in 1984 with the stocking of 125 fingerlings. Current hybrid Muskellunge stocking is conducted biennially, on odd numbered years, at a rate of 1.0 fingerlings per surface acre (235 fish). Gervais Lake is also stocked with surplus hybrid Muskellunge fry in years they are available. The 2017 Walleye catch rate on Gervias Lake was 2.00 per gill net, the same as the 2011 survey but down from the 2005 and 2000 surveys (See Table 1). The average size of Walleye in the gill nets was 18.7 inches and sampled fish ranged in age from 3 up to 10 years old. The Northern Pike catch rate of 9.20 fish per gill net is the highest on record for Gervais Lake. High numbers of Northern Pike can reduce the success of Walleye and Tiger Muskelunge stocking due to predation. The average size pike in 2017 was 25.5 inches long. Gervais Lake is in the North-Central Zone for Northern Pike management which allows a harvest of 10 fish, with 2 allowed over 26 inches, and a protected slot between 22 and 26 inches. Table 1. Historic gill net catch per net table for Gervais Lake: Northern Pike (NOP); Walleye (WAE) 1958 1975 1980 1985 1990 1995 2000 2005 2011 2017 NOP 0.75 7.50 6.75 5.25 2.67 1.00 0.17 1.33 6.20 9.20 WAE 0.75 0.00 4.50 0.00 0.33 3.17 3.50 4.50 2.00 2.00 The panfish population in Gervais Lake is very typical of most metro area lakes. Yellow Perch, Black Crappie and Bluegill were all sampled within their normal range of abundance. Black Crappie averaged 7.7 inches long and perch were 6.7 inches long. The Bluegill catch rate was 49 per trap net which is two to three times lower than than the previous two surveys. A lower density Bluegill population can result in an increased size structure, but this was not evident in the 2017 survey yet. The average Bluegill was 6.0 inches long and only eight of 683 fish measured more than 7.50 inches long.

Based on Minnesota DNR survey data, anglers target Northern Pike, Largemouth Bass, Muskellunge, Walleye, and White Crappie in Gervais. 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 Gervais. Check the DNR LakeFinder page for current access details before you go.

Gervais has a maximum depth of 41 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Gervais is from 2021.

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