Rock

Rock Lake is a 261 acre lake located three miles east of Casino in southern Cass County. Rock Lake has a maximum depth of 17 feet and is susceptible to partial winterkill events during severe winters with at least two partial kills happening in the past decade. The management plan calls for stocking Walleye fry (230,000) after severe winterkill events. Walleye were stocked in 2019 and 2022. No Walleye were sampled in this survey. A standard survey using gill nets and trap nets was conducted in August of 2025 to assess fish populations and provide angler information. Northern Pike had a gill net catch of 16.5/net. Fish ranged from 17.0 to 29.0 inches with an average of 20.2 inches. Northern Pike in the protected 22-26 inch slot made up 3% of the catch with 6% at least 26 inches in length. The population is dominated by young fish with age 2 and 3 fish making up 91% of the catch. Anglers can expect lots of action on smaller fish. Anglers will find plenty of Black Crappie in Rock, but they run on the small side. Gill nets had a catch of 17.5/net with fish ranging from 4.6 to 8.2 inches with an average of 5.9 inches. Trap nets had a catch of 2.3/net with fish ranging from 5.0 to 9.6 inches with an average of 6.9 inches. For both gear types combined, 14% of the catch was at least 8 inches in length. Bluegills had a trap net catch of 9.8/net. They also ran on the small side with fish ranging from 3.0 to 6.7 inches with an average of 4.6 inches. Anglers may want to target Yellow Perch in Rock. Fish ranged from 5.3 to 10.9 inches with an average of 7.7 inches. Yellow Perch at least 8 inches in length made up 47% of the catch. Other species sampled included Bowfin (Dogfish), Brown Bullhead, Hybrid Sunfish, Pumpkinseed, White Sucker and Yellow Bullhead.

Special Problems and Concerns: Occasional winterkills due to its weedy and shallow condition.Additional Field Notes: Observed one beaver lodge, muskrat activity and campground had only two camping outfits at time of survey and two additional people using beach. Campground does get heavy use on weekends.Present Fish Status Population: Northern pike abundance is good (4.5/lift) with all sizes present and growth rate varying from slow to good rate. Black bullheads are very abundant but quite small. Brown bullheads are also very abundant and average 0.25 pounds. Bluegills are of moderate abundance (15 per trapnet) with majority belonging to the 2 and 3 year class and showing good growth rate. Black crappies are present in good numbers with size small and fish belonging to years classes three years and younger. Walleyes are present in high numbers and large sizes. Fry and fingerlings stocking from 1979 through 1982 took hold. No yellow perch were caught in nets. Many fish species present, consist mainly of young fish which is typical of winterkill lakes.

Special Problems and Concerns: Rock Lake has had severe winterkills over the past few years.Additional Field Notes: A pair of loons were sighted on the lake.Present Fish Population Status: A high population of small northerns and black bullheads are present due to very recent heavy winterkills.

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

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

Rock has a maximum depth of 17 feet, per Minnesota DNR data.

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

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