Sonju

Sonju Lake is a 37 acre lake with a maximum depth of 8 feet located 5 miles northeast of Finland Minnesota. There is a carry in access down a fairly steep hill from the Sonju Lake road to the northwest corner of the lake. Other than the access there is no development on the lake shore, it is entirely in public ownership. Sonju Lake connects to the East Branch of the Baptism River, a designated trout stream by way of an unnamed creek. The purpose of the spring 2016 targeted survey was to assess if any Brook Trout remained in the lake following the decision to discontinue stocking in 2014. No Brook Trout were sampled during the 2016 survey. It is possible that Brook Trout may move into the lake seasonally from the East Branch of the Baptism River, but is unlikely that they can maintain a population in the lake year round due to the limited depth. The only fish sampled during the 2016 survey were White Sucker and Common Shiner. With the notable exception of summer 2009 (an exceptionally cold summer) the trout fishery in Sonju Lake and net catch in Sonju Lake have been poor. Surveys of winter dissolved oxygen have revealed that it is inadequate to support Brook Trout through the winter; due to the shallow depth of the lake (max depth 8 feet) summer temperatures are not suitable for Brook Trout either. Most likely as a result of these two issues, observed survival of stocked Brook Trout was very poor. Brook Trout stocking on Sonju Lake was discontinued in 2014. From a game fish perspective, this lake will not be of interest to most anglers as there are no permanent gamefish populations. It however is a scenic lake and may be of interest to canoers and duck hunters, it has been used in the past as a source of bait for local minnow dealers.

Sonju is a 37 acre lake with a maximum depth of eight feet located four miles north of Finland, MN in Lake County. The lake is on the south side of Sonju Lake Road and is accessed by a 30 yard trail down a steep hill. Maneuvering boats up and down the access is quite difficult; the lake is best fished by canoe or, in winter, through the ice. However, the Sonju Lake Road is not consistently plowed in winter, making alternative transportation necessary for accessing the lake at times. Sonju's shoreline is mixed forest and bog; the substrate is primarily muck, except some small areas of sand and gravel around the inlets. The fish community includes brook trout, white suckers, golden shiners, and pearl dace. Historically brown trout were stocked in the lake, but brown trout have not been stocked since 2001 and they were not present in the most recent surveys (2009 and 2012). The 2012 survey found a very low brook trout abundance in Sonju Lake with only 13 brook trout caught. The trout averaged 8 inches and 0.26 pounds; the largest trout sampled was 9 inches and 0.34 pounds. In both the 2009 and 2012 assessments all the trout sampled were yearlings stocked the spring prior to the assessment. Low winter dissolved oxygen levels likely result in annual brook trout winterkills in Sonju. In contrast to the brook trout, extremely high numbers of white suckers were sampled in 2012. White sucker catch rates were about 30 times higher than average for lakes similar to Sonju. Although high abundances of white suckers are not uncommon in Sonju, the 2012 catch rate was the highest in netting history.

Sonju Lake gets light annual fishing pressure, with highest fishing pressure usually near the May opener for open-water angling and the January opener of the winter trout season. Brook trout yearlings are stocked annually in this designated stream trout lake. Low dissolved oxygen levels in winter and warm water temperatures in summer can stress the trout population in both seasons. Water quality measurements show that fishing early in the winter trout season, or the early or late part of the open-water trout season, should be the most productive periods for trout angling on Sonju Lake. Winter access is 4.2 miles from the nearest plowed road (Sonju Lake Road) unless there are logging operations in the Sonju Lake area. Summer access is a 30 yard trail from the Sonju Lake Road to the northwest end of the lake.

Based on Minnesota DNR survey data, anglers target Brown Trout and Brook Trout in Sonju. See the full species list above for catch rates, size structure, and quality scores.

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

Sonju has a maximum depth of 8 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Sonju is from 2012. Surveys this old should be treated with some caution — fish populations change over time.

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