|Nearest Town: Grand Rapids
Primary County: Itasca
Survey Date: 06/25/2012
Inventory Number: 31058600
|Did you know? Minnesota waters support 153 species of fish.|
|Species||Number of fish per net||
Average Fish Weight (lbs)
Normal Range (lbs)
|Black Crappie||Trap net||0.11||0.5 - 2.2||0.53||0.3 - 0.5|
|Gill net||3.89||0.3 - 1.7||0.23||0.2 - 0.5|
|Bluegill||Trap net||14.22||7.7 - 43.4||0.07||0.1 - 0.2|
|Largemouth Bass||Trap net||0.44||0.4 - 1.5||0.31||0.2 - 0.7|
|Gill net||1.11||0.5 - 1.7||1.84||0.5 - 1.2|
|Northern Pike||Trap net||0.33||N/A||2.79||N/A|
|Gill net||11.11||2.2 - 8.7||1.71||1.5 - 3.2|
|Pumpkinseed||Trap net||0.78||1.4 - 5.9||0.02||0.1 - 0.2|
|Rock Bass||Trap net||0.33||0.8 - 3.7||0.27||0.2 - 0.4|
|Gill net||1.11||0.7 - 4.4||0.62||0.2 - 0.4|
|Smallmouth Bass||Gill net||0.11||0.2 - 1.6||3.31||0.8 - 1.8|
|Walleye||Trap net||0.11||0.2 - 0.7||0.12||0.7 - 2.8|
|Gill net||0.67||1.0 - 5.0||2.35||1.2 - 3.0|
|White Sucker||Gill net||1.56||0.5 - 2.0||2.33||1.6 - 2.6|
|Yellow Perch||Gill net||4.11||1.5 - 13.8||0.14||0.1 - 0.2|
|Species||Number of fish caught in each category (inches)|
|For the record, the largest Longnose Sucker taken in Minnesota weighed 3 lbs., 10.6 oz. and was caught: |
Statistics: 21" length, 10.25" girth
Fish Stocked by Species for the Last Ten Years
|Privately Stocked Fish|
|* indicates privately stocked fish. Private stocking includes fish purchased by the DNR for stocking and fish purchased and stocked by private citizens and sporting groups.|
|Stocking Fish Sizes|
|Fry - Newly hatched fish that are ready to be stocked usually called "swim-ups". Walleye fry are 1/3 of an inch or around 8 mm.|
|Fingerling - Fingerlings are one to six months old and can range from a size of one to twelve inches depending on the species. Walleye fingerlings range from three to eight inches each fall.|
|Yearling - Yearling fish are at least one year old. A one-year-old fish can range from three to twenty inches depending on the species. Walleye yearlings average from six to twelve inches.|
|Adult - Adult fish are fish that have reached maturity. Depending on the species, maturity can be reached at two years of age. Walleye reach maturity between the ages of four and six years.|
Johnson Lake is a 492-acre lake located thirteen miles north of Grand Rapids, MN. The lake is deep with a maximum depth of 88 ft and is clear with a Secchi disk reading of 17 ft. There is a concrete public access on the south shore and much of the shoreline is in the Chippewa National Forest. Primary fish species include northern pike, largemouth bass, panfish and walleye.
Gill net catch rates for northern pike have been steadily increasing. Catch rates in 1997, 2005 and 2012 were 7.8, 9.3, and 11.1/net. Catch rates in 2005 and 2012 were higher than the expected range for similar lakes. Size structure in 2012 was poor and only two fish out of 100 sampled exceeded 26 inches. Size structure has also generally been poor in past assessments. Growth was slow, but within 15% of the statewide average with fish averaging 22 inches by age six. Increasing catch rates are a concern because competition for prey increases as the population increases and growth remains slow or declines. Size structure is unlikely to improve with high abundance and slow growth.
Largemouth and smallmouth bass were sampled by electrofishing on May 30th. Largemouth bass catch rate was 36.6/hour and one smallmouth bass was sampled for a catch rate of 0.7/hour. Electrofishing was also conducted in 1993 and 1997 when catch rates for largemouth bass were 21.0/hour and 3.8/hour. Smallmouth bass catch rates for the same assessments were 4.5/hour and 0.8/hour. Largemouth bass size structure in 2012 was moderate with fish up to 17 inches sampled. Ageing indicated eight year classes and growth was similar to the statewide average with fish averaging 15.1 inches by age six.
Black crappie catch rate in gill nets was 3.9/net which was higher than the expected range, however, only one black crappie was sampled in trap nets for a catch rate of 0.1/net which was lower than the expected range. Catch rates in the last two assessments have been less than 1.0/net for both gill nets and trap nets. Size structure was good with fish up to 11 inches sampled. Size structure has historically been good with fish up to 12 inches sampled in past assessments. Growth was similar to the lake class average with fish averaging 9.7 inches at age six. Seven year classes were sampled indicating consistent recruitment.
Bluegill trap net catch rate was 14.2/net which was within the expected range for similar lakes. Catch rates in past assessments have been similar and have varied from 7.0 to 26.4/net, with no trend of increasing or decreasing abundance. Size structure was very poor and few fish larger than 6 inches were sampled. Size structure has historically been poor, however some fish up to 8 inches have been sampled in past assessments. Scales were not collected for age and growth analysis.
The walleye gill net catch continues to be low and only six fish were sampled for a catch rate of 0.7/net which was lower than the expected range. Catch rates have only exceeded 2.0/net in the first assessment in 1955. Walleye frylings were recently stocked in 2009 and 2011. Walleye fingerlings, yearlings and adults were also stocked in 2004 and 2007. Size structure was good with fish up to 22 inches sampled. Walleye from six different year classes were sampled with fish up to age 12. Since only six fish were sampled from six different year classes it is difficult to determine what improvement if any walleye stocking has made to the population. Growth was similar to the statewide average with fish averaging 18.2 inches at age six.
Yellow perch gill net catch was 4.1/net, which was similar to the expected range. The catch rate declined from 12.1/net in the 2005 assessment, but is similar to the previous six assessments when catch rates have varied from 0.3 to 4.4/net. Size structure was moderate with some fish up to 11 inches sampled. Yellow perch are an important prey species for northern pike and walleye. Low catch rates reduce the ability of Johnson Lake to support a larger walleye population.
Other species sampled included pumpkinseed sunfish, rock bass and white sucker. Nearshore seining and backpack electrofishing also sampled bluntnose minnow.
Lakeshore owners may affect fish populations not only through harvesting fish, but also through land use practices. It is important to leave a 30 to 50 ft buffer strip of native vegetation along the shoreline to prevent erosion and provide habitat for fish and wildlife. Nonfunctioning septic systems can also lead to water quality problems. Good water quality and fish populations are the direct result of good land use practices. Anglers can also help to improve the size structure of the fish community by practicing selective harvest.
|For more information on this lake, contact:||Lake maps can be obtained from:|
For general DNR Information, contact:
DNR Information Center
500 Lafayette Road
St. Paul, MN 55155-4040
TDD: (651) 296-6157 or (888) MINNDNR
Turn in Poachers (TIP):
Toll-free: (800) 652-9093