Grants

A trap net survey was conducted on Grants Lake on July 12-13, 2022 by Index of Biological Integrity (IBI) Program Staff. Nine trap nets were set along the shoreline in locations that encompassed multiple habitat types. Bluegill comprised a majority of the trap net catch by number. The number of Bluegill sampled per net was above the 25% quartile and below the 50% quartile for similar Lake Class 31 lakes and the average length was 5.5 inches, with 22% over seven inches. Bluegill, Hybrid Sunfish, Bowfin, and Northern Pike comprised a majority of the trap net catch by biomass. The fish data collected in this trap net survey were combined with data from an August 2020 gill net survey and July 2020 survey of nearshore fishes 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. Blacknose Shiner, Iowa Darter, and Smallmouth 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 Grants Lake is in good health as indicated by an FIBI score above the impairment threshold for aquatic life use determined for similar lakes. Data from this survey will contribute biological information about the health of the fish community to the Long Prairie River Watershed assessment process in coordination with MN Pollution Control Agency.

Grants Lake is a moderately productive, 177-acre basin located south of Holmes City. A concrete public access is found on the northwest shoreline, off Country Lane SW. Average depth is 25.0 feet. Maximum depth is 60.0 feet. Water clarity is high (8.0 feet). Despite good water clarity, aquatic vegetation is not overly abundant due to predominantly sand substrates and steeply sloped shorelines. A standard fisheries survey was completed during summer 2020 to provide updated information on the fish community of Grants Lake. Standard survey components typically include spring electrofishing, gill nets, and trap nets. However, due to safety concerns during the COVID-19 pandemic, gill nets were the only component used in 2020. Grants Lake has supported an above-average Walleye population for several decades. Currently, catch rates (1.8/gill net) have dipped below historical levels, but still approximate the average of similar lakes in Minnesota. Individuals averaged 16.5 inches with the majority between 15.0 and 20.0 inches. The oldest Walleye was twelve-years-old. A young 2019 year class was present and this year class will likely provide good fishing opportunities in the next several years. Walleye fry are stocked every third year to maintain the population. Initially documented in 2009, Smallmouth Bass are believed to have been illegally introduced into Grants Lake. Following introduction, catch rates have increased (7.0/gill net) and a high proportion of the individuals collected were young. Maximum length of Smallmouth Bass was 17.8 inches. Largemouth Bass are also relatively common. Twelve individuals, ranging from 13.3 to 17.4 inches in length, were sampled with gill nets. Northern Pike catch rates (4.7/gill net) approximate the average of previous surveys. Most pike were smaller individuals. The largest pike measured was 32.7 inches. Anglers are encouraged to take advantage of recently liberalized pike harvest regulations. Grants Lake falls in the North-central Zone where all pike 22-26 inches must be immediately released. Anglers can keep up to 10 pike but no more than two can be longer than 26 inches. Harvesting smaller pike will help improve size structure of this population. Eight Black Crappies were sampled with gill nets. Mean and maximum lengths were 10.5 and 12.0 inches, respectively. Bluegill and Yellow Perch are also present in Grants Lake, but none were collected with gill nets in 2020. Other species recorded in 2020 included Common Carp, White Sucker, Black and Yellow Bullhead. The next standard fisheries survey is tentatively scheduled for 2026. Grants Lake has been designated as an infested waterbody due to the presence of zebra mussels and flowering rush. These aquatic invasive species were first confirmed in 2019. Anglers are reminded to drain boats and equipment and remove aquatic vegetation prior to moving between bodies of water to minimize the risk of transferring aquatic invasive species.

This nearshore survey was conducted during summer 2020 to assess populations of non-game species and small game fish using backpack electrofishing and seining. Backpack electrofishing and/or seining were conducted at 10 stations, representing a variety of habitat types, along the shoreline of Grants Lake. The survey was conducted during the five-year sampling window for intensive monitoring efforts within the Long Prairie River watershed, and will be contributing to a watershed assessment process in coordination with Minnesota Pollution Control Agency. Seventeen species were collected during this survey. Four species (Blacknose Shiner, Iowa Darter, Mimic Shiner, and Smallmouth Bass) were considered "intolerant" and one species (Green Sunfish) was considered "tolerant" based on current tolerance classifications for Minnesota lakes. Nearshore catch data will be used along with gill and trap net catch data to develop an Index of Biotic Integrity (IBI) score, which is indicative of the health of Grants Lake.

Based on Minnesota DNR survey data, anglers target Hybrid Sunfish, Black Crappie, Walleye, Largemouth Bass, and Smallmouth Bass in Grants. See the full species list above for catch rates, size structure, and quality scores.

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

Grants has a maximum depth of 60 feet and a mean depth of 25 feet, per Minnesota DNR data.

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

Yes — Grants has confirmed flowering rush and zebra mussel. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.