Iowa

Iowa Lake, located south of Fairmont on the Iowa-Minnesota border in Martin County, is a 732 acre border water lake with a maximum depth of 9.4 feet and an average depth in the 3 to 4 foot range. Iowa Lake is located near the top of its watershed on South Creek, a tributary to the Blue Earth River. South Silver Lake is the source of South Creek and connected to Iowa Lake via a culvert. Iowa Lake is a large shallow lake that is susceptible to low dissolved oxygen in the winter months and high water temperatures in the summer. In addition, Iowa Lake is commonly dominated by Common Carp, Black Bullhead, and Bigmouth Buffalo, which degrade water quality and habitat. Iowa Lake is managed for Yellow Perch, Northern Pike, Black Crappie, White Crappie, and Walleye. A standard survey was completed the week of July 31, 2023 using two gill nets and nine trap nets to monitor fish populations. Historically, Yellow Perch catch rates have ranged from 0.0 per gill net in 2017 to 103.3 in 2005, averaging 44.1 per gill net since 1990. In 2023, the Yellow Perch catch rate at Iowa Lake was 20.0 per gill net, an increase from the 2017 catch rate of 0.0 per gill net and within the expected range of catch rates for similar lakes (3.0 to 22.5 per gill net). The increase in abundance was likely the result of the adult Yellow Perch that were stocked in 2018, as they likely produced future year classes of Yellow Perch. Lengths of Yellow Perch ranged from 5.2 to 9.5 inches and averaged 7.9 inches. The Walleye gill net catch rate of 20.0 per gill net was the highest catch ever recorded on Iowa Lake, exceeding the expected range of catch rates for similar lakes (3.2 to 15.3 per gill net). Four year classes of Walleye were sampled (2019, 2020, 2021, and 2022), with the 2022 stocked year class accounting for 93 percent of the sample (N=37 out of 40). 2019 (N=1 fish) and 2020 (N=1 fish) were unstocked years, so these Walleye were likely illegally moved by an angler, as natural reproduction is highly unlikely in Iowa Lake. Lengths of Walleye ranged from 4.9 to 19.4 inches and averaged 10.7 inches. The strong 2022 year class should provide good angling in a year or two, and should provide a top level predator to help control Bullhead and Common Carp populations. The 2023 Black Crappie catch rate was the highest ever recorded on Iowa Lake at 16.3 per trap net. It exceeds the expected range of catch rates for similar lakes (1.0 to 12.3 per gill net). Historically, catch rates ranged from 0.0 per gill net in 2017 to 11.0 per gill net in 1994 and averaged 5.4 per gill net since 1990. Black Crappie lengths ranged from 5.7 to 11.8 inches and averaged 7.3 inches. It appears that Black Crappie are the dominant Crappies species in Iowa Lake currently, as only 3 White Crappie were captured in the survey. No Northern Pike were sampled in 2023 in Iowa Lake despite adults and fry being stocked in 2018 and 2022, respectively, indicating that these stockings may have been mostly unsuccessful. Four Channel Catfish were sampled in the survey which marks the first time that Channel Catfish have been sampled in Iowa Lake. Channel Catfish lengths ranged from 16.3 to 18.7 inches and averaged 17.9 inches. The Black Bullhead catch rate was 41.0 per gill net which is within the expected range of catch rates for similar lakes (4.6 to 83.0 per gill net). Black Bullhead ranged in length from 5.7 to 11.7 inches and averaged 9.2 inches. Other species sampled included Bigmouth Buffalo, Bluegill, Common Carp, Freshwater Drum, Hybrid Sunfish, Largemouth Bass, Orangespotted Sunfish, White Bass, and Yellow Bullhead.

Iowa Lake, located south of Fairmont on the Iowa-Minnesota border in Martin County, is a 732 acre lake with a maximum depth of 9.4 feet and an average depth in the 3 to 4 foot range. Iowa Lake is located near the top of its watershed on South Creek, a tributary to the Blue Earth River. South Silver Lake is the source of South Creek and connected to Iowa Lake via a culvert. Iowa Lake is a large shallow lake that is susceptible to low dissolved oxygen in the winter months and high water temperatures in the summer. In addition, Iowa Lake is commonly dominated by Common Carp and Black Bullhead, both of which degrade water quality. Iowa Lake is currently managed for Yellow Perch, Northern Pike, and both species of Crappie (Black and White). Yellow Perch and Northern Pike are species that are tolerant of low dissolved oxygen in winter and crappie are typically tolerant to degraded habitat. A lake survey was completed from August 28th to August 30th, 2017 to assess the fish community. YELLOW PERCH Only 3 Yellow Perch were caught in survey nets. The Yellow Perch ranged in length from just shy of 6 inches to just shy of 10 inches. The historical average catch rate of Yellow Perch is 48.9 per gill net and 4.8 per trap net. The last survey on Iowa Lake was in 2005 when the catch rates were 103.3 per gill net and 0.7 per trap net. The 2017 trap net catch rate of 0.4 per net is not alarming when compared to the trap net catch rate in 2005, but the gill net catch rate difference is a major red flag. Based on the fish survey, it would appear that there was a fairly significant winterkill in southwest Minnesota shallow lakes during the winter of 2013-2014. Iowa Lake must have been a lake that was affected. South Silver did not show any effect of winterkill, but East Chain Lake downstream did show a significant winterkill that year. Iowa Lake will be restocked with pre-spawn Yellow Perch during the spring of 2018 to boost the population. NORTHERN PIKE No Northern Pike were caught in the gill nets or trap nets in 2017. In 2005, the catch rates were 0 in gill nets and 0.1 in trap nets. Northern Pike abundance has been low on Iowa Lake for many years, even without winterkill. It is potentially a lake that is in need of drastic habitat improvement before Northern Pike will be a successful member of the fish community. Northern Pike fry could be restocked in 2018, however, Walleye may be better suited as a predator to positively impact Iowa Lake with a degraded habitat and water quality. Walleye utilize Bullhead as prey while Northern Pike will not readily consume Bullhead. CRAPPIE No White Crappie were caught and only 4 Black Crappie were caught, all in trap nets, in 2017. The Black Crappie ranged in length from just over 3 inches to just under 7 inches. The small size indicates that the remaining Black Crappie are successfully reproducing and Crappie are repopulating. However, additional broodstock will be stocked to boost spawning success. Crappie are well suited for Iowa Lake with degraded habitat and water quality. Crappie have the best gamefish potential on Iowa Lake and are desired by area anglers. OTHER SPECIES Bigmouth Buffalo, Black Bullhead, Bluegill, Common Carp, Freshwater Drum, White Bass, and Yellow Bullhead were also caught in the survey nets. All the listed species are also found upstream in South Silver Lake and could have been immigrant fish prior to the 2013-2014 winterkill, especially Bluegill and Freshwater Drum (species sensitive to low dissolved oxygen). Common Carp were the most abundant species by weight in trap nets and gill nets followed by Bigmouth Buffalo, Freshwater Drum, and Black Bullhead indicating a lake that is overwhelmed by undesirable species. COOPERATIVE MANAGEMENT WITH IOWA The Iowa DNR and Minnesota DNR have interest in maintaining a fishable sportfish population in Iowa Lake. Each state has representatives that meet yearly to discuss management of border lakes. Recent discussion on Iowa Lake has been a desire to improve gamefish abundance as well as improving habitat. Reestablishment of gamefish populations in Iowa Lake will be a cooperative effort by Iowa DNR stocking as well as Minnesota DNR stocking. There will be an ability to coordinate efforts to maximize the effectiveness of stocking utilizing species that each state stocks well. The Iowa DNR has an excellent Northern Pike rearing operation in Spirit Lake, IA that could be utilized to restock Iowa Lake. The Minnesota DNR has the ability to produce inexpensive Walleye fry that could be utilized to restock Iowa Lake. Crappie and Yellow Perch will be stocked by Minnesota DNR as well. A resurvey or targeted sampling of the fish community by 2021 will be necessary to check on the recovery of the lake. By Nate Hodgins

A Minnesota - Iowa border lake, 732 acre Iowa Lake is located in Martin County and has a maximum depth of 9.4 feet. The lake is presently managed primarily for yellow perch and secondarily for northern pike, black crappie, and white crappie.Our 2005 sampling efforts revealed an impressive yellow perch population. Iowa's perch numbers are well above average for lakes with similar characteristics. Fish sampled ranged in length from just over 4 inches to just over 12 inches and appeared very well fed based on their plumpness. Yellow perch sampled averaged about 1/3 of a pound and aging of the fish revealed 4 different year classes.The northern pike population of Iowa Lake is low compared to similar lakes. Only 1 pike was sampled during the 2005 assessment. In our effort to provide a northern pike fishery, nearly 53,000 fry were stocked in 2003 and 4,000 fingerlings in 2005. We plan to continue stocking northern pike fingerlings once every three years. Iowa's black crappie population is at an all-time low, but is still well within the "normal" range for similar lakes. Sampled fish ranged in length from 4 to 11 inches and, like the perch population, were very plump and apparently having no trouble finding adequate food. The average weight of the black crappies caught during the assessment was just under 1/2 pound. Scale aging revealed 4 age classes within the lake with most of the fish sampled coming from a strong 2004 year class. Even though our results may seem to suggest that Iowa Lake's black crappie population is low, the fish are of very catchable size for anglers and quite a few nice "eaters" were seen. Iowa's population has historically been quite high compared to similar lakes and thus, 2005's "historical low" simply put the lake's black crappie population into the "normal" range.Although only 1 white crappie was sampled during the 2005 assessment, it was nearly 10 inches in length and weighed over 1/2 pound. Both crappie species (black and white) are managed together in Iowa Lake. Due to the sufficient black crappie population, no further crappie stocking is planned at this time.Black bullhead and common carp numbers in Iowa Lake are of some concern. Both species are at or near historical highs within the basin. We plan to continue to encourage commercial fishermen to harvest Iowa in an effort to control the bullhead and carp populations to the best of our ability.Other species sampled in the 2005 Iowa Lake assessment were bigmouth buffalo, orangespotted sunfish, bluegill, golden shiner, and yellow bullhead.To promote and maintain healthy fish populations, pollution and other inputs need to be controlled. Fish habitats are directly affected by water quality. Nutrient, sediment and other waste inputs can drastically alter the biological, chemical, and physical components of a lake. It is paramount to maintain if not improve the water quality of Iowa Lake through watershed management to preserve this fishery for future generations to enjoy.Prepared by Leslie George

Based on Minnesota DNR survey data, anglers target Channel Catfish, Northern Pike, Walleye, Yellow Perch, and Black Crappie in Iowa. See the full species list above for catch rates, size structure, and quality scores.

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

Iowa has a maximum depth of 9.4 feet, per Minnesota DNR data.

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

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