Crooked Lake is a 115-acre lake located five miles east of Marcell, MN. The lake is moderately deep with a maximum depth of 46 ft and was clear with a Secchi disk reading of 12 ft. There is a gravel public access on the east shore and the lake is lightly developed with much of the shoreline in public ownership. Previous water chemistry sampling had low alkalinity of 20 ppm indicating low fertility. Primary fish species include northern pike, largemouth bass and panfish.
The northern pike gill net catch rate was 7.0/net and was within the expected range for similar lakes. Catch rates in two past assessments have been slightly less at 2.7 and 5.3/net. Size structure was poor with few fish larger than 24 inches sampled. Growth was slow, but within 15% of the statewide average for fish up to age seven. Only two age eight fish were sampled and length at age was only 23.7 inches compared to 30.5 inches for the statewide average. Growth may be slower for larger fish due to the lack of larger prey such as white sucker or tullibee.
Largemouth were sampled by night electrofishing on May 21st and caught 71 fish for a catch rate of 49.4/hour indicating moderate abundance. Previous assessments have not sampled largemouth bass in gill nets or trap nets, however, notes in the lake file indicate largemouth bass were present. Size structure was good with fish up to 19 inches sampled. Growth was slow, but within 15% of the statewide average with fish averaging 16.2 inches at age nine. Ageing indicated a long lived population with fish up to age 11.
The bluegill trap net catch rate was 8.2/net which was lower than the expected range. Catch rates in past assessments have also been low varying from 2.8 to 7.4/net. Size structure was poor with no fish 8 inches or larger sampled. Size structure has historically been poor, with few fish larger than 7 inches sampled in past assessments. Growth was slightly faster than the lake class average with fish averaging 6.6 inches at age seven. Fish up to age 10 were sampled indicating a long lived population.
The black crappie catch rate was 2.0/net in both gill nets and trap nets. Both catch rates were within the expected range for similar lakes. Catch rates in past assessments have been similar varying from 1.0 to 2.7/gill net and 0.6 to 1.0/trap net. Size structure was good with fish up to 11 inches sampled. Growth was slightly slower than the lake class average with fish averaging 9.2 inches at age six. Seven year classes were sampled indicating consistent recruitment.
Yellow perch gill net catch was 2.0/net, which was within the expected range for similar lakes. Catch rates in previous assessments were similar and varied from 1.0 to 4.7/gill net. Size structure was poor and no fish larger than 7 inches were sampled. Yellow perch are an important prey species for northern pike and low catch rates compared to many lakes may reduce growth rates and the ability to produce larger fish.
Golden shiner were the only other species sampled by gill nets or trap nets. Nearshore seining and backpack electrofishing also sampled bluntnose minnow and central mudminnow.