Walleye and Sauger in the Prairie State

Photos courtesy of the author.

LaSalle Fish Hatchery, acquired by the Illinois Department of Natural Resources (IDNR) in 1994, once served as a research center/hatchery and was operated by Southern Illinois University-Carbondale. In an area locally known as the “South Prairie,” most people drive past the locked gate and an “Authorized Personnel Only” sign on the way to a LaSalle Lake boat ramp, not realizing that they had just passed the LaSalle Fish Hatchery.

Located in 5 miles south of Marseilles in LaSalle County, the hatchery is on property IDNR leases from Exelon Corporation. The facility consists of 16 earth-bottomed ponds (10 are 2.5 acres in size; three are 2.0 acres; three 1.5 acres) that receive water from LaSalle Cooling Lake, along with a hatchery building, well water supply system, storage building and an office trailer.

The mission of the hatchery is to fulfill fish stocking recommendations developed by IDNR District Fisheries Biologists and to improve fishing in various water bodies in the state. The location of LaSalle Fish Hatchery makes it ideal for production of sauger and walleye, which comprise roughly 90 percent of the total number of fish produced there annually. The hatchery also produces saugeye (a hybrid of walleye and sauger), hybrid striped bass (white bass/striped bass hybrid), largemouth bass, smallmouth bass, bluegill and redear sunfish. Since 1994, the more than 598 million fish—roughly 20.6 million fish per year—produced at LaSalle Hatchery have been stocked in public waters or transferred to other state hatcheries and rearing ponds.

The culture season typically begins in mid-March when adult sauger are collected at the Illinois River Battle on the River tournament which is hosted by the Spring Valley Walleye Club and Masters Walleye Circuit (Figure 1). After the teams weigh their catch, adult sauger are transported to the hatchery or returned to the Illinois River depending on their spawning condition. In late March, IDNR stream biologists collect walleye broodfish by electrofishing the Kankakee River. In early April, IDNR district fisheries biologists collect walleye broodfish from the Fox Chain O’Lakes. Adult female fish transported to the hatchery are separated into two groups: those ready to spawn and those not quite ready to spawn. After spawning, the broodfish are returned to the lake or river where they were collected.

Female sauger and walleye are spawned using the “dry method.” Eggs are expressed from the fish by applying a gentle stroking motion from just behind the gills to the vent (Figure 2) and placed into stainless-steel mixing bowls. Semen from adult males is added to the bowl and the addition of water will activate the sperm. The mixture is gently stirred for two minutes with a Canada goose wing feather. Next, a solution of Fullers Earth is added to the bowl and gently stirred for at least three minutes to remove adhesiveness from the eggs. A water rinse then removes the Fullers Earth.

The eggs are then water-hardened by floating the trays in water tanks for two hours (Figure 3). Swelling to twice their original size, the eggs become firmer and more resistant to damage from moving and handling by hatchery staff. The trays of fertilized eggs are then protected from many pathogens and viruses with a 15-minute bath in a tank containing 100ppm povidone iodine. The disinfected egg trays are placed in a tank containing flowing well water which allows the eggs to be siphoned into McDonald hatching jars (Figure 4). Approximately 1 million sauger eggs and 500,000 walleye eggs are incubated in each jar. Water maintained at 58º F flows through the jars, keeping the eggs gently rolling until they begin to hatch in eight days.

Fry take minimal caretaking before stocking. They are kept in hatchery tanks for 3 to 5 days where they survive on their internal food source, called a yolk sac, while they develop teeth which will allow them to feed. When sauger fry reach 8 to 9 mm in size they are stocked into the Illinois River or the LaSalle hatchery ponds where they can grow into fingerlings. At 10 to 11 mm in length, walleye fry are stocked into the Fox Chain O’Lakes or hatchery ponds at both LaSalle and Jake Wolf Memorial (Mason County) fish hatcheries for fingerling production.

Hatchery ponds are filled with water to half capacity in preparation for release of the fry. A week to 10 days prior to moving fry the hatchery pond is fertilized with alfalfa meal which will develop the rich plankton food necessary for the fish. Sauger fry are stocked at 200,000/acre and walleye fry at 150,000 fry/acre in these hatchery ponds. Fry begin feeding on zooplankton (microscopic invertebrates) in the ponds soon after stocking. Additional water is added to the ponds 10 to 14 days post stocking. Additional alfalfa meal is placed in the ponds throughout the culture period to stimulate the necessary zooplankton food supply.

Not all fertilizers help the walleye and sauger. Nutrients from the fertilizers also grow filamentous algae and rooted vegetation in the ponds. Harvesting fingerlings from ponds with vegetation dense is difficult. Therefore, vegetation must be frequently chemically treated in May and June as the fingerlings grow.

Fingerlings can quickly exhaust the entire zooplankton food supply if the water temperature of the pond rises above 68º F. When this occurs, the ponds are partially harvested with a 300-foot-long by 12-foot-deep seine (Figure 6). Removing a portion of the fish in the pond for stocking allows the remaining fish to continue to grow (Figure 7).

The walleye and sauger reach fingerling size of 1.5 inches in approximately 40 days depending on the weather and water temperatures (Figure 8). Seining must be done early in the morning when the wind speeds are light and water temperatures are cool to reduce stress on the fingerling fish. Seining walleye and sauger is generally complete by mid-June when the fingerlings are up to 2.2 inches in length (Figure 9).

Fingerlings are immediately transported to nearby stocking sites. Those slated for stocking at more distant locations are held in tanks inside the fish hatchery for up to three days (Figure 10). Upon arrival at the stocking location, the fingerlings are acclimated with water from lake or river and then released (Figure 11).

Back at the hatchery, the ponds are drained and readied for the process of raising largemouth bass, smallmouth bass and bluegill during the summer and fall months. By late fall those fish will be shipped out for stocking and the ponds readied for the return of walleye and sauger production.

Sauger and walleye produced at the LaSalle Fish Hatchery supplement existing fish populations where poor recruitment has occurred, establish and maintain sport fisheries in the public waters of Illinois and increase successful angling opportunities throughout the state (Figure 12). The fish hatchery system is funded from fishing license sales and a grant from the U.S. Fish and Wildlife Service that originates with excise taxes on fishing equipment.

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Rick Bushman is the Hatchery Manager at the Illinois Department Natural Resources’ LaSalle Fish Hatchery where he has worked for 28 years as the Fish Culturist and Assistant Manager. He graduated with a Bachelor of Science degree from the University of Wisconsin-Stevens Point, double majoring in Water Resources-Fisheries Emphasis and Biology-Aquatic Emphasis. He earned a Master of Science degree from Iowa State University, majoring in Fisheries Biology. Bushman worked on fisheries projects in Arizona and Iowa prior to beginning his career with the then Illinois Department of Conservation.