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Lake Information

County: Massac

Acreage: 452

Average Depth: 3.12 feet

Shoreline Length: 3.5 miles

Recreational Amenities

Boat Fishing? Unrestricted, no wake

Boat Ramps? Yes

Boat Rental? Yes

Skiing? No

Swimming? No

Picnicking? Yes

Camping? No

Maps are not intended for navigation.

There are no zebra mussels in this lake.

Lake Status Summary  ( Full PDF Report )

Click here for a list of all reports.



Fish Status


Very Good

Bluegill were substantially more abundant in 2022 than in the previous year at 473 per hour of electrofishing, 34% were larger than 6 inches (within desirable management goals), with 13 percent of the sampled population exceeding 7 inches. Bluegill body condition was still excellent.



Channel catfish are generally not a large component of the annual Mermet Lake electrofishing sample, and 2022 followed this trend (11/hr). Annual channel catfish stockings help support a fishery which is very popular with the angling public.


Very Good

White crappie were sampled at a rate much better than previous years (47/hr) and quality and condition as evident by percentage of fish over 8 inches (PSD=60%), percentage of fish over 10 inches (RSD-10”=13%) and high body condition (relative weight=94) were much better. Black crappie prospects are similar, with fish sampled at a much higher rate (53/hr) with much better quality and condition indices.


Very Good

Largemouth bass were collected at a rate of 85 per hour in fall 2022, nearly double last year. 70% of these fish were larger than 12 inches, which easily met the management plan goal. Bass larger than the old 14 inch minimum size limit made up 52% of the sample, while 34% exceeded the newly implemented length limit of 16 inches (April 1, 2016). Bass condition remained excellent.



: A decent number of Redear sunfish were sampled in 2021 (27/hr). The lake sustains a phenomenal Redear fishery but these fish can be difficult to sample at certain times of the year. Quality and condition of these fish were phenomenal, and 40% of the fish sampled were at least 10 inches long.

Location: Mermet Lake is a shallow, 452-acre, IDNR-owned impoundment located in Massac County approximately 10 miles north of Metropolis.

Description: Mermet was originally built as a water supply for flooding adjacent wetland compartments for waterfowl hunting, but sport fish flourished when stocked, and the lake has been managed for fishing for more than 50 years. Curlyleaf pondweed, an exotic aquatic plant, invaded Mermet in 1999, and has caused occasional summer fish kills since then, but annual herbicide treatments have generally been successful at controlling the impacts of this plant in recent years, allowing the sport fish population to slowly recover.

Additional Lake Information: The outboard motor limit is 10 hp, but boats with larger outboards are allowed to operate at no-wake speed. Mermet Lake is closed to fishing during the duck season.

Site Regulations:
Largemouth bass: 16” minimum length limit, 3 per day creel
Black and white crappie: 25 per day creel
Channel catfish: 6 per day creel

Contact Information:
Mermet Site Office
IDNR Fisheries Biologist, Luke Nelson

There were 1 tournaments held on this waterbody in 2020.

Species Total Fish Caught
Largemouth Bass 39

Top 5 Largemouth Bass caught on this waterbody in 2020 tournaments:

1     4.60 lbs

Top 5 Bag Weights of Largemouth Bass caught on this waterbody in 2020 tournaments:

1 114.79 lbs
2 0.00 lbs

Multiple day tournaments are listed with *end date and

Interested in participating in one of these public tournaments? Contact us with tournament ID for more information.

2020-2021 Approved or Pending Tournaments
Start Date ID Approval Ramp Location Bank/Boat
Max Boats Species Youth? Open to Public?
April-0725732ApprovedClub Ramp boat
20Largemouth Bass
April-1425871ApprovedClub Ramp boat
20Largemouth Bass
Smallmouth Bass
Spotted Bass