Johanna

Lake Johanna is a shallow prairie lake located in southeastern Pope County. The lake is comprised of a large southern basin with a maximum depth of 10 feet, and a northern basin and many smaller bays that are generally less than 6 feet deep. The many shallow bays are often densely vegetated and sustain clearer water. Water transparency exceeded 10 feet at time of the June 2022 survey. Water quality and clarity in the main basin can decline during summer months, especially after curly leaf pondweed deteriorates. Fish community structure and fishing quality continue to be influenced by severity and frequency of winterkill events. Fish predation by abundant populations of American White Pelican and Double-crested Cormorant may also affect this fishery. Most of the angling pressure in the summer months consists of anglers targeting Largemouth Bass and Northern Pike. Recreational activities in the winter are typically focused on Northern Pike spearing. A standard survey was conducted in 2022 to assess the current fish community. Partial winterkill events since the last survey have likely claimed some of the larger sunfish, bass, and Walleye in Lake Johanna. The fish community was dominated by Northern Pike, sunfish, and bullheads during the 2022 survey. Northern Pike abundance is near the long term average for Lake Johanna and almost half of the pike caught in the survey were over 26 inches long. Brown Bullhead and Yellow Bullhead catch rates were high and many of these fish were large. Compared to other species in the lake, Northern Pike and bullheads are more tolerant of low oxygen levels during winterkill events and this is why they are often more abundant and larger than other species in the lake. Bluegill numbers were the highest ever observed in Lake Johanna, but a majority of the fish were less than 6 inches and only 2 years old. Largemouth Bass numbers were moderate and the largest fish observed was 17 inches. Black Crappie abundance is also low and many of the fish were small at the time of the survey. Walleye abundance continues to decline, despite continued stocking efforts. Fish growth rates in Lake Johanna are fast, and in the absence of continued winterkill events, many species should reach larger sizes in just a few years. Lake Johanna is not currently known to have any invasive species. Recreational users should take necessary precautions to prevent the spread of invasive species. Drain all water and remove all aquatic vegetation from your boat and trailer when leaving any body of water.

This targeted survey was completed to determine extent of winterkill following the severe 2018-2019 winter. Early-spring trap netting results suggested that winterkill severity was low and restorative stockings were not warranted. Gamefish species present included Black Crappie, Bluegill, Largemouth Bass, Northern Pike, Pumpkinseed, and Walleye.

Lake Johanna is a shallow prairie lake located in southeastern Pope County. The lake is comprised of two basins having a combined surface area of 1,584 acres. The main basin has a maximum depth of 13 feet. Water quality and clarity can be poor during summer months in response to wind and wave-induced re-suspension of sediments and subsequent algal blooms. Water transparency exceeded 10.0 feet at time of the June 2016 survey. With exception of a dense curly-leaf pondweed stand during early summer months, aquatic vegetation coverage and densities can be considered "moderate". Fish community structure and fishing quality are influenced by occasional winterkill events. A standard survey was conducted in 2016 to assess the current fish community. A partial winterkill event in the winter of 2013-2014 may have claimed some of the older, larger fish in the population. However, as is the case in many winterkill situations, fish growth remains fast and the fishery should recover quickly. Compared to other gamefish in Lake Johanna, Northern Pike are more tolerant of winterkill conditions and thus proved to be very abundant. Mean length was almost 24 inches. Several pike over 30 inches were also recorded in the catch. Walleye catch rates declined during 2016, but a modest Walleye fishery still remains in response to supplemental fry stockings and some natural recruitment. Largemouth Bass and Bluegill were abundant, but most captures were smaller, younger individuals. Average length of Largemouth Bass was only 7 inches. A few older fish up to 19 inches in total length were observed. Most Bluegills were less than 6 inches long, however, a modest number of memorable-size fish measuring up to 11 inches were caught during the survey. Black Crappie catch rates remained low, but crappie are not always sampled efficiently during summer surveys. Bullhead abundance has remained well below historic levels during the last few surveys. As long as no severe winterkills occur during the next few years, Lake Johanna should provide excellent angling opportunities. Water clarity in the winter months is typically very high. With an elevated density of Northern Pike in the lake, winter spearing opportunities should be good. The Lake Johanna Scientific and Natural Area (SNA) is located in the southern basin of Lake Johanna. This SNA is a unique island that is home to one of the largest and most diverse nesting colonies for colonial waterbirds (great blue herons, double-crested cormorants, great egrets, black-crowned night herons, and American white pelicans) in Minnesota. The SNA is designated as a public use unit and is open to the public for nature observation and general educational and research activities. However, it is closed to the public from April 1 through July 15 to avoid disturbance during the potential nesting season.

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

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

Johanna has a maximum depth of 10 feet and a mean depth of 7 feet, per Minnesota DNR data.

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

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