A population assessment of Calhoun Lake was conducted during early July of 2013. Calhoun is a moderately sized (618 acres) and moderately productive lake located in Kandiyohi County. The maximum depth is 13 feet. The immediate watershed is composed of agricultural row crop areas, hardwood tree stands, wetlands, grasslands, and 55 residential homes. The Middle Fork Crow River enters Calhoun along the southwest corner. Calhoun is connected to Green Lake via a bypass channel of the Middle Fork Crow River and the Green Lake outlet marsh. A DNR public access is located along the south shore. Large emergent vegetation (bulrush, cattails) stands are present along the west and south portions of the lake. Water nutrient (total phosphorus=0.022 mg/l) and clarity (secchi=5.5 feet) results were good during July 14, 2013 (MNPCA). Submergent vegetation species are varied and dense (northern milfoil, muskgrass, filamentous algae, water moss, various pondweed species) in Calhoun. Eurasian milfoil was first noted in scattered low densities of Calhoun, especially near the Middle Fork Crow River Inlet area, during 2010. Eurasian milfoil has been present upstream in nearby Green Lake since 2000. Shoalwater substrates consist mostly of sand, silt, and gravel. Calhoun is a popular bluegill, largemouth bass, black crappie and northern pike (spearing and angling) fishery.
Largemouth bass numbers were abundant (4.50 fish/gillnet) and the average size was moderate (12.8 inches, 1.16 pounds) in 2013. The Calhoun largemouth bass historical average catch rate is 2.83 fish/gillnet.
Black crappie numbers were low (2.00 fish/gillnet, 1.67 fish/trapnet), but the average size was moderate (0.54 pounds and 9.33 inches). The black crappie historical average catch rates were 4.39 fish/gillnet and 2.00 fish/trapnet for Calhoun. Black crappie growth rates were below the Spicer Area normal ranges for ages 1-4. The 2008 year class comprised 53% of the 2013 black crappie gillnet and trapnet catch.
Northern pike numbers were exceedingly abundant in 2013 (20.00 fish/gillnet) compared to the historical average (13.65 fish/gillnet) for Calhoun. The northern pike average size was small (1.94 pounds and 20.00 inches) from gillnets. The northern pike historical average weight is 2.49 pounds from gillnets. The 2013 catch rate of larger (>28 inches) northern pike was low to moderate (1.50 fish/gillnet). Northern pike growth rates were below the Spicer Area normal ranges for ages 1-6 except for ages 3-4. Approximately 67% of the northern pike captured in the 2013 summer resurvey nets were from the 2011 year class.
Yellow perch numbers were low (1.00 fish/gillnet) in 2013. The yellow perch historical average catch rate is 9.27 fish/gillnet for Calhoun. The 2013 yellow perch average size was moderate (0.27 pounds and 8.31 inches) from gillnets.
Walleye numbers were moderately abundant (2.50 fish/gillnet) in 2013 compared to the Calhoun historical average (1.54 fish/gillnet). The 2013 walleye average size was moderately large (1.73 pounds and 16.34 inches) from gillnets. The walleye population is due largely to the recent stockings of larger sized fish that are less susceptible to predation by largemouth bass and northern pike. Walleye growth rates were within the Spicer Area normal ranges for ages 1-4. The 2010 year class comprised 75% of the 2013 walleye catch from gillnets and trapnets.
Bluegill numbers were moderate (23.44 fish/trapnet) in 2013. The bluegill historical catch rate is 56.65 fish/trapnet for Calhoun. The 2013 bluegill average size (0.19 pounds and 6.12 inches from trapnets) was above the Calhoun historical average (0.12 pounds). There were moderate numbers of moderated sized (>6 inches) bluegill (14.33 fish/trapnet) captured in 2013. Bluegill growth rates in Calhoun Lake were below the Spicer Area normal ranges for ages 1-5, and within the normal ranges for ages 6-8. The 2008 year class comprised 79% of the total bluegill catch in the 2013 nets. Spicer DNR fisheries personnel had conducted removal operations of smaller bluegill (<6.00 inches) from Calhoun in the past to promote better bluegill growth and for stocking needs in other local lakes lacking suitable natural reproduction/survival, however removal efforts are no longer conducted due to the presence of Eurasian milfoil.
Black bullhead numbers were low (0.50 fish/gillnet, 0.44 fish/trapnet) in 2013. The black bullhead average size was large (1.08 pounds and 12.28 inches) from gillnets.
Other fish species of special interest captured in the 2013 gillnets included moderate numbers of carp (1.22 fish/trapnet), low numbers of pumpkinseed sunfish (0.78 fish/trapnet), and high numbers of yellow bullhead (25.50 fish/gillnet). The 2013 average weights were 9.13 pounds, 0.28 pounds, and 0.57 pounds for carp, pumpkinseed sunfish, and yellow bullhead respectively.
Current fish management activities on Calhoun Lake include monitoring the fish population on a periodic basis, protecting native aquatic vegetation through the permit process, preventing and educating about the spread of invasive species, operating the outlet dam to prevent winterkill, and stocking various fish species as warranted. The Calhoun fishery will be surveyed in the 2018 summer for all fish species.
- Eurasian Watermilfoil
- Zebra Mussel
Recreational activities such as recreational boating, angling, waterfowl hunting, and diving may spread aquatic invasive species. Some aquatic invasive species can attach to boats, while others can become tangled on propellers, anchor lines, or boat trailers. Many species can survive in bilge water, ballast tanks, and motors or may hide in dirt or sand that clings to nets, buckets, anchors, and waders. Fortunately, completing simple steps can prevent the transport of aquatic invasive species.