Illinois River - Marseilles Pool

White Bass

Average

White bass are a short-lived and fast-growing species that provide excellent sport fishing opportunities during the early spring spawning runs or mid-summer feeding frenzies of gizzard shad. White bass numbers can be cyclic, because they require a degree of flowing water for spawning success. White bass have been absent from our annual fall electrofishing surveys in the Marseilles Pool for the last several years, but have started showing up again in small numbers. There is a one-meal-per-week contaminant advisory on white bass in Marseilles Pool due to PCB detection in the flesh. PCB contamination in fish is a remnant of past pollution from a group of manmade chemicals before their production was banned in 1979. Trim the fat, particularly around the belly, and allow fat to drip off the fish when cooking to minimize exposure to PCBs.

Crappie spp.

Average

Both black crappie and white crappie are found in the upper Illinois River. The 2025 fish community survey produced few fish. No crappie were collected in the 2025 Marseilles Pool electrofishing survey. Black crappie are stocked by IDNR – Division of Fisheries State Hatcheries in the upper Illinois River to supplement the population when hatchery production allows. Backwaters, side channels and main channel border areas with submerged brush are the best locations for crappie.

Smallmouth Bass

Very Good

The Marseilles Pool had the second highest catch rate of smallmouth bass over the last 10 years for that pool with a catch rate of 17 fish/hour electrofishing. Smallmouth bass ranged in size from 3-18 inches and up to 3.6 pounds. The IDNR – Division of Fisheries State Hatcheries annually stocks smallmouth bass in the upper Illinois River to supplement year class strength.

Sauger

Average

Some of the best sauger and walleye fishing is downstream of the Starved Rock Lock and Dam, but they may also be caught in deep waters of the Marseilles Pool during the day or in the shallows at night. Few sauger or walleye are collected during day-time electrofishing surveys. The IDNR – Division of Fisheries State Hatcheries annually stock sauger fry in the upper pools of the Illinois River. In collaboration with our research partners, a sauger/walleye study will be conducted over the next few years to determine stocking success and other population characteristic measures to help better manage the sauger fishery in the upper Illinois River.

Largemouth Bass

Average

The 2025 fall electrofishing survey resulted in an average catch rate (17/hour) of Largemouth Bass in the Marseilles Pool ranging in size from 1-15 inches and weighing up to 2.5 pounds.

Flathead Catfish

Very Good

Flathead catfish provide a chance to catch a big fish in the upper Illinois River. Hoop net surveys conducted in 2023 resulted in the collection of 69 flathead catfish ranging from 16 – 42 inches weighing up to 39 pounds. Trophy-sized fish exceeding 36 inches and 25 pounds are common in the Marseilles Pool of the Illinois River. Fish the deep holes and main channel border near current breaks for trophy flathead catfish.

Channel Catfish

Very Good

Channel catfish are abundant in the upper Illinois River. Illinois River hoop netting is on a 4 year rotation by pool. Hoop net surveys conducted in the Starved Rock and Marseilles pools in 2023 yielded a total catch of 695 channel catfish ranging from 12-28 inches weighing up to 8 pounds. Notable habitats for channel catfish are main channel border (area between the navigation channel and the river bank), and side channels with current. The Marseilles and Dresden dam tailwaters are notable channel catfish areas. There remains a contaminant advisory on all channel catfish in the Starved Rock and Marseilles pools due to PCB detection in the flesh (no more than 1 meal/month). PCB contamination in fish is a remnant of past pollution from a group of manmade chemicals before their production was banned in 1979. Trim the fat, particularly around the belly, and allow fat to drip off the fish when cooking to minimize exposure to PCBs.