Sampling the central channel provides additional information on fish assemblages in a large boatable river in the U.S. Midwest

It is a challenge to adequately characterize the fish assemblages of large rivers because of their sizes and high spatial–temporal habitat heterogeneity. Multiple sampling methods are often needed, but their uses increase cost and present difficulty for data standardization. In this study, we examined how much new information central-channel electrofishing sampling could add to typical shoreline electrofishing in a large and relatively shallow river, the lower Wabash River, in the U.S. Midwest. We found that the two types of samples differed markedly in species composition, and each was strongly associated with a subset of species. Shoreline samples captured more fish individuals and species, and reached higher functional diversity, but central-channel samples often captured several large benthivore and migratory species such as Redhorse and Shovelnose Sturgeon. Central-channel electrofishing appears to be a quick and low-cost method to supplement shoreline sampling in monitoring and assessing large shallow rivers.