The Long-Term Survey and Assessment of Large River Fishes in Illinois (historically known as Long-Term Electro Fishing, or LTEF) program at IRBS completes annual stratified-random fish sampling using boat-mounted pulsed-direct current (DC) electrofishing on the Illinois Waterway from southwest Chicago to Alton, IL, and on the Upper Mississippi River in pools 16-22 from Muscatine, IA to Hannibal, MO (2009-present). This program tracks long-term changes in fish communities in response to broad-scale environmental changes. The LTEF program provides data to the Illinois DNR to inform its management of fish populations through setting recreational and commercial fishing limits, fish stocking, and assessing and listing threatened and endangered species. LTEF data is also used to maintain regulations (compliance with statutes), inventory and characterize natural areas, prioritize and evaluate conservation actions, and conduct impact assessments. Besides providing data to the Illinois DNR, LTEF program data are also used for graduate student and external-partner research projects and is shared with other programs such as the Multi-Agency Monitoring (MAM) program, which is used to evaluate the success of monitoring and management programs for invasive carps.
LTEF fish sampling is conducted in three, six-week sampling periods from June 15 to October 31, primarily in main-channel border habitat, along with some historical side-channel fixed sites in the Illinois Waterway (see The history of the LTEF Program below). Fish data collected includes species identification, weights, lengths, and the occurrences of external lesions, parasites, or deformities. Ancillary water quality data are also collected at each site and includes dissolved oxygen, temperature, specific conductance, Secchi transparency, and surface velocity. The current LTEF DC sampling protocol was modeled after the Upper Mississippi River Restoration Program’s Long-Term Resource Monitoring (LTRM) element on the Upper Mississippi River System.
The LTEF project was expanded in 2009 (Upper Mississippi River), 2010 (Ohio and Wabash rivers), and 2013 (Kankakee and Iroquois rivers) to increase spatial coverage of fish monitoring in Illinois’ rivers. To accommodate this expansion, staff from the Illinois Natural History Survey at the Great Rivers Field Station and at University of Illinois Urbana-Champaign (UIUC), Eastern Illinois University, and Southern Illinois University all contribute to sampling. Although the sampling on the Kankakee and Iroquois rivers conducted by UIUC was discontinued in 2020, the LTEF program still samples 919 of the 1200 major river miles in the state of Illinois – that’s 74% of all the major rivers that are covered by the LTEF program, including 100% of the Illinois portions of the Illinois River, Wabash River, and Ohio River.
Funding for the LTEF program has been provided by Sport Fish Restoration funds through the U.S. Fish and Wildlife Service and the Illinois Department of Natural Resources (project F-101-R) since 1989.
The History of the LTEF Program
In 1957, William C. Starrett, former Director of the Forbes Biological Station at Havana, IL, initiated what came to be known as the Long-Term Electro Fishing program (LTEF) to relate spatial and temporal changes in the fish community to changes in water and habitat quality throughout the entire Illinois Waterway.
Fishes were collected annually at fixed side-channel border sites throughout the Illinois Waterway utilizing boat-mounted 3-phase alternating current (AC) electrofishing gear. There was a total of 28 collection sites, with 27 sites on the Illinois Waterway (25 sites on the Illinois River and 2 sites on the lower Des Plaines River), and a single site on Pool 26 of the Mississippi River below Grafton, IL. Sites were sampled for one hour during late August and September each year, when water levels were at seasonal lows. Sampling was not conducted if water levels exceed specific criteria established for each site or the water temperature fell below 50° F. The database contains data for most years from 1957-2015; funding lapses and high-water conditions precluded 8 years of sampling over the entire span of the historical LTEF project.
The historical AC fixed-site sampling done by the LTEF program was discontinued in 2016, marking the end of an era for the historic AC electrofishing. We still sample approximately half of the historic AC side-channel border sites as part of the current program, but with the pulsed-DC gear and protocol (see above).
Historical LTEF AC electrofishing on the Illinois Waterway in 1963 and 2013.
This project is coordinated by Jason DeBoer, Andrya Whitten Harris, and Rob Mooney at IRBS.