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THOMPSON/FLAG LAKE


Lake Information

County: Fulton

Acreage: 4000

Recreational Amenities

Boat Fishing? Electric only

Boat Ramps? Yes

Boat Rental? No

Skiing? No

Swimming? No

Camping? No


There are no zebra mussels in this lake.

Lake Status Summary  ( Full PDF Report )

Click here for a list of all reports.

Species

Rank

Avg Wt.
(pounds)

Avg.
Length
(inches)

Fish Status

BLUEGILL

Good

0.4 lbs

8

In 2014, the bluegill survey samples represent a bluegill population with good distribution from 1.6 to 10.2 inches long. Good recruitment has now occurred. The body condition was good for the fish over 5 inches. 17% of the bluegill sampled were over 8 inches in length.

BOWFIN

Good

0.6 lbs

27

The bowfin population was sampled by 74 fish from 16.1 to 31.9 inches in 2014. Several year classes appear to be present. The body condition of these fish was extremely good.

CHANNEL CATFISH

Good

4.8 lbs

24

12 channel catfish were sampled in 2014. 9 of the fish were from 12.2 to 15 inches long and indicate a new year class was recruited from the original brood fish.

CRAPPIE

Very Good

N/A

N/A

The black crappie sample appears to represent a small YOY class from 4.7 to 5.9 inches long and multiple year clasess from 6.7 to 14.2 inches long. And then a few brood fish from the 2007 stocking from 16.5 to 17.3 inches long were sampled. The body condition was still a good for the fish over 8 inches. However, some of the larger fish were starting to show a decrease in body condition with age. For the first time since the brood stocking in 2007, 10 white crappie were sampled in 2012, 1 fish in 2013, and 63 fish in 2014. The 2014 white crappie sample was composed primarily of fish from 8.3 to 10.2 inches long. The body condition average was good. This dense crappie population with large fish will feed on the gizzard shad population and also provide additional predation upon potential exotic fish species reproduction.

LARGEMOUTH BASS

Very Good

0.3 lbs

9

In 2014, the largemouth bass population was sampled by electrofishing and large mesh trap nets. From the fall boat electrofishing surveys in 2014. the collection rate was 3.16 fish per minute in the main ditch and NW Thompson Lake area. A typical management objective for bass over 8 inches is a collection rate of 1 fish per minute. In 2014, the average 7+ year old bass was 16.7 inches long and weighed 2.49 pounds. The growth rate for the 2007 year class has slowed to a static level. The largemouth bass population was defined by an average Young Of the Year class from 2 to 6 inches in length. Then good recruitment from the group of 1+ bass from 7 to 12 inches. Small year classes were produced for the 2+ to 5+ age groups. The 6+ and 7+ year classes continue to be the “dominant” composition of the population and average from 14 to 19 inches in length. The average body condition of the fish over 8 inches was good.

PUMPKINSEED

Good

N/A

4

In 2014 the pumpkinseed population was samples appear to represent YOY fish up to 3.1 inches in length and several year classes up to 9.1 inches in length. The body condition was a good for the adult fish.

Location: The Nature Conservancy's Emiquon Preserve is adjacent to the Illinois River in Fulton County, Illinois, approximately 1 mile northwest of Havana and 3 miles southeast of Lewistown.

Description: Historically, what is now the Emiquon Preserve included two backwater lakes, Thompson Lake and Flag Lake, and was argued to have been one of the better hunting and fishing complexes in the Illinois River Valley if not the whole Midwest. From the early 1920s through the present, most of the property currently owned by the Conservancy was managed for agriculture, most recently primarily for intensive row-crop production. In 2007, the site pumps were shut off and the water level in the site was allowed to rise and reform the lakes. The current Thompson/Flag Lake covers approximately 4,000 surface acres. The lake topography is two large shallow basins with deep water ditches dissecting it. In midsummer, the lake basins can be 70% covered with aquatic vegetation.

History and Status of the Sport Fishery: In 2007, The Nature Conservancy entered into a cooperative fish management agreement with the Illinois Department of Natural Resources for the Emiquon Preserve. The water bodies on the site underwent an immediate fish rehabilitation project to remove exotic fish species. The IDNR initiated fish restocking in 2007 with brood fish that included: llargemouth bass, white crappie, black crappie, bluegill, bowfin, spotted gar, channel catfish, brown bullhead, warmouth, orangespotted sunfish, pumpkinseed sunfish, golden shiner, brook silverside, and blackstripe topminnow. IDNR fish stockings and surveys have resulted in the potential of at least 43 fish species now present in the lake.

Additional Lake Information: Public access to the water bodies on the Emiquon Preserve is limited to registered boats. Free annual registration to access the site for all users is required and available at the adjacent Dickson Mounds State Museum. Only electric trolling motors are allowed. No gas motors are allowed on the boats.

2 pole and line fishing only. No bank fishing is currently allowed. In the future, limited bank fishing sites may be developed. A concrete boat ramp with a gravel parking lot for 25 vehicle/trailers is present and a boardwalk, visitor area and canoe launch.

The site contains an inviolate refuge from public access. This refuge will attempt to serve as a limited disturbance area for all of the wildlife utilizing the Preserve. This refuge encompasses approximately the eastern half of the former Thompson Lake basin, all of the former Flag Lake basin and then to the Illinois River levee. This refuge area is designated with marked buoys and signs. The access time to the water bodies is sunrise to sunset. This access is year round, except during the Central Zone waterfowl hunting season. During the Central Zone waterfowl hunting season, no water access is allowed on hunting days. Currently waterfowl is allowed 3 days a week, thereby allowing fishing access 4 days a week. Ice fishing is allowed when practical on the entire lake basin.

Contact Information:
The Nature Conservancy site office
309-547-2730
IDNR Fisheries County Fish Biologist
309-446-9143