Thole is a shallow, productive 105-acre lake located south of Shakopee in Scott County. It is bordered to the east by Lake O'Dowd and to the south by Schneider Lake. Before development, all three lakes were connected and undivided by paved roads. Thole has a maximum depth of 12 feet and early-August water clarity near 2.5 ft. The oxygen-temperature profile taken then reflected reasonable mixing and moderate oxygen for 2/3 of its depth. During open water months, a fishing pier, integrated into the DNR-owned public access, is maintained for use. During most winters, an aerator is run by the O'Dowd Lake Chain Association. A standard population assessment consisting of gill nets and trap nets was conducted in 2013 to characterize the game fish community.
Northern Pike abundance was high. Gillnet catch averaged 7.4/net, which is slightly higher than the 75th percentile value based on similar lakes. Size ranged from 14.6 to 30.5 inches, averaging 21.8 inches and 2.3 lbs. Size structure appeared to be balanced with desirable numbers of larger and smaller fish. Most pike (72 percent) were from the 2008 and 2009 year classes (ages 4 and 5). Ages ranged from 3-10. Growth was average when compared to other similar lakes in the West Metro Management Area. Northern Pike were 19.0 inches at age 3 and 23.6 inches at age 6.
Black Crappie abundance (13.4/gill net) was moderately high and near the 75th percentile value (14.7/gill net) when compared to other similar lakes. Size structure was small. The majority (75 percent) of Black Crappie were between 5.5 and 6.5 inches. The average size was 5.9 inches and 0.1 lbs; size ranged from 4.3-10.5 inches. The 2011 year class (age 2) dominated the sample (81 percent), however, crappie up to age 7 were in the population. Growth through age 3 was slightly better than average when compared to other similar lakes in the West Metro Area. Age-3 crappie averaged 7.5 inches in length.
Spring trap nets yielded 22.8 Bluegill per set, which is moderately high compared to other similar lakes statewide. The size structure was skewed toward larger individuals. A large proportion (58 percent) of Bluegill were between 6.5 and 7.5 inches. The average fish was 6.7 inches/0.2 lbs, with a length range of 3.4-8.5 inches. Ages ranged from 2 to 9. The most abundant year class was 2007 (age-6) and comprised 32 percent of the sample. Growth was consistently slow for all ages of Bluegill.
Passive sampling gear, such as trap and gill nets, are not effective methods for collecting Largemouth Bass, so the 6 total bass sampled this assessment under-represent lake's abundance. Electrofishing is the typical method for
Largemouth Bass assessments but was not conducted this survey.
Black Bullhead were moderately abundant (42/gill net). They averaged 9.1 inches and ranged from 5.2 to 12.0 inches. Other species sampled in low-to-moderate abundances were Golden Shiner, Green Sunfish, hybrid sunfish, and Pumpkinseed.
Summer gillnet sampling turned up one peculiar catch- one 27.7-inch Shovelnose Sturgeon. This fish was most likely introduced through illegal stocking and the DNR has no reason to believe sturgeon populations are established in Thole Lake.
- Eurasian Watermilfoil
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.