AUTHORS: Olivia Wertman, Eastern Illinois University; Daniel R. Roth, Eastern Illinois University; Eden L. Effert-Fanta, Eastern Illinois University; Robert E. Colombo, Eastern Illinois University
ABSTRACT: Fish communities face many threats such as climate change, natural disasters, invasive species, and anthropogenic impacts such as fertilizers or other pollutants. These threats may affect the communities by removing breeding ground, impacting food sources, introducing new competition, or causing harmful algal blooms. Programs to monitor the communities for these changes are necessary. One program is the Long-Term Survey and Assessment of Large River Fishes, LTEF, which assesses fish populations in the large rivers of Illinois. This program was initiated on the Illinois River in the 1950’s and expanded to include the Wabash River in 2010. Annual direct current electrofishing surveys are utilized to collect fish from 102 random sites across five reaches in the lower 200 miles of the Wabash River over three time periods from June to October. The fish are identified by species and measured to their total length and weight. This study aims to assess how fish communities of the Lower Wabash have changed from 2010-2023. To describe functional changes to the fish community, the USGS Fish Traits Database was used to define guilds (trophic, reproductive, habitat) into which the collected fishes were separated. An earlier study found benthic invertivore, general invertivore, omnivore, and piscivore guilds showed increasing trends, but not all were significant. Previous trends showed significant changes in native planktivore (Gizzard Shad, Dorosoma cepedianum) and invasive planktivore (Silver Carp, Hypophthalmichthys molitrix) biomass. Community assemblages remained relatively similar over time, with changes in Cyprinid species abundances contributing the largest amount of assemblage variation during most years. This data is important for understanding the state of fish communities in the Lower Wabash River, assisting with conservation and management efforts, and shows the need for continued monitoring of our rivers.
