Hickory

A targeted survey of nearshore fish species in Hickory Lake was conducted on August 14-15th, 2023, by Index of Biological Integrity (IBI) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot seine, where possible. Backpack electrofishing was completed at ten sampling stations. Similarly, a 50-foot seine was used to sample seven stations and no seine was used at three stations due to site conditions. Nearshore sampling captured twenty species of fish including seven species that are intolerant of disturbance (i.e., Banded Killifish, Blackchin Shiner, Blacknose Shiner, Iowa Darter, Least Darter, Logperch, and Rock Bass) and zero that are tolerant of disturbance. The nearshore data were combined with trap net and gill net data from a June 2023 survey to describe the fish community and provide a fish-based IBI (FIBI) score. The FIBI uses fish community data to measure a lake's health, and the types of fish species present can help identify any stressors that may be negatively affecting the lake environment. In Minnesota lakes, certain fish species cannot survive without clean water and a healthy habitat (e.g., Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead and Common Carp). The FIBI score, composed of several fish community diversity and composition metrics, indicates the overall health of a lake by comparing it to what is expected for a healthy lake. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Results from this survey provide evidence that the fish community in Hickory Lake is Lake is healthy as indicated by an FIBI score that exceeds the exceptional use threshold determined for similar lakes. These results are similar to previous survey findings, which indicated that Hickory Lake is fully supporting for aquatic life use. The survey results will be considered when the biological health of the lake is assessed during the Mississippi River - Brainerd Watershed assessment process, which will be completed in coordination with MN Pollution Control Agency.

Hickory Lake is located on the Ripple River chain of lakes between Little Pine and Spirit lakes, approximately six miles south of Aitkin. The lake is 197 acres with 56% of the lake being less than 15 feet deep and a maximum depth of 32 feet. Public access is limited to a small sand access and shoreline within a Minnesota Department of Transportation wayside area at the inlet from the Ripple River. Boaters can also gain access via a private campground on the west side of the lake. Shallow water substrates consist primarily of sand and silt, though areas of detritus, muck, gravel, rubble, and boulders may be found as well. The aquatic plant community is relatively diverse with 35 species present and is integral to maintaining good water quality as well as maintaining healthy fish populations. Emergent plants such as bulrush are important for shoreline protection, maintaining water quality, and provide essential spawning habitat for bass and panfish species. Submerged plants provide food and cover needed by fish and other aquatic species. While historically, Hickory has had moderately clear water (Secchi about 11 feet during past surveys), this survey had a Secchi depth of 24 feet, which has not previously been observed. Lack of significant spring run-off in 2023 along with newly established populations of Zebra Mussels in upstream Little Pine and Farm Island Lakes, water clarity may tend to be clearer in the future. Hickory Lake is managed primarily for Bluegill and Northern Pike and secondarily for Walleye and Black Crappie. Hickory Lake has been regularly stocked with Walleyes in alternate years since 1954. Although the numbers and sizes have varied, alternate year fingerling stocking was most common until 2017 when the management changed to a fry based stocking program. In addition to stocked Walleye, a spawning area on the Ripple River between Little Pine and Hickory Lake appears to be successful in producing some fish, and movement of fish from adjacent waters has also been observed. The 2023 Walleye catch of 0.8 per gill net was similar to past catches on Hickory, which average 1.1 per gill net, and is comparable to other similar lakes, yet does not meet the management goal of at least 3 per gill net. Average length and weight were 19.5 inches and 2.3 pounds. The Northern Pike catch was above average when compared to similar lakes at 14.3/gill net in 2023. The 2023 catch was the highest catch rate that has been observed and exceeds the range of recommended levels (5-13 per gill net) for Hickory Lake. Past catches have ranged from 7.0 to 13.5 per gill net, with an average of 11.1 per gill net. Average length and weight were 19.2 inches and 1.7 pounds, with about 13% measuring at least 26 inches, and several over 30" in length that were observed in the sample. Bluegill were caught in relatively modest numbers at 9.4 per trap net and with decent quality at over 15% greater than 8 inches. Previous Bluegill catches have ranged from 8.22 per trap net to 51 per trap net and averaged 26.8 per trap net. Prior to 2000, there were more Bluegills in the population but with a much poorer size structure (less than 2% over 8 inches). Bluegill size structure met the management goals in 2023 for size and numbers. Black Crappies were caught in low numbers at 0.7 per gill net and 0.2 per trap net. Past Black Crappie catches have typically been low, ranging up to 1.7 per gill net and 0.8 per trap net. Crappie size structure was good in 2023, averaging 9" with a maximum length of 11.3".

Walleye have been stocked in Hickory Lake regularly since 1954. Although the stocking density and sizes have varied, alternate year fingerling stocking was the most common method used. The current stocking strategy of 2 pounds per littoral acre of fingerlings, stocked in alternate (odd-numbered) years, began in 2007. This assessment was conducted to assist in evaluating the current stocking plan. Walleye gill net catches during the 6 previous nettings have ranged from 0.4 to 2.0/net with mean and median values of 1.1 and 1.0/net, respectively. The 2015 walleye catch of 1.0/gill net was similar to these past catches, though it was still below the management goal of 3-5/gill net. The 6 walleye caught in the 2015 survey ranged in size from 15.1 to 19.4 inches, with a mean length of 19.4 inches. Five year classes were present, which met the management goal of 4 year classes. Four out of the 6 fish were from non-stocked years. This was similar to what was observed in a 2010 ice-out assessment when multiple non-stocked year classes were observed in the 65 fish sample from the spring spawning run (2010 Hickory special assessment, 4/14/2010). In 2015, two of the four walleyes from non-stocked years were from the 2010 year class, which also corresponded with a non-stocked year in neighboring and connected Farm Island and Spirit Lakes, suggesting that these were indeed naturally reproduced fish. Northern pike numbers remained high and were above the normal range for lake class 29 lakes at 12.8/ gill net, although nearly 20% were over 24 inches long. High northern pike numbers have likely been contributing to poor walleye fingerling survival and ultimately the lower walleye density at Hickory Lake. Black crappie and yellow perch numbers remained low.

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

We don't have a confirmed public access point on record for Hickory. Check the DNR LakeFinder page for current access details before you go.

Hickory has a maximum depth of 32 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Hickory is from 2023.

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