Current-Year Manuscripts

Transactions of the Illinois State Academy of Science [Volume 115 (2022)]


Status Assessment of the State-Threatened Gravel Chub (Erimystax x-punctatus) in Illinois

Authors: Jeremy S. Tiemann, Joshua L. Sherwood, and Andrew J. Stites

The Gravel Chub Erimystax x-punctatus (Family Leuciscidae) is an imperiled minnow with a disjunct distribution in Illinois. Due to its affinity for deep, swift flowing water, this species is often difficult to collect with traditional sampling methods and might be overlooked during fish sampling surveys. We performed a status assessment of this rare species with methods that target benthic-dwelling fishes by sampling at 50 sites throughout the species range. In non-wadeable areas, sites were accessed via boat and sampled using a mini-Missouri trawl, whereas in wadeable streams, sites were sampled by kick-seining swift-flowing rocky areas. Erimystax x-punctatus was found at 43% of the sites sampled – 41.3% of the sites trawled and 50% of the sites kick-seined – in depths varying from 0.3 to 2.1 m (mean: 0.78 m ± 0.39 m SD) and stream velocities ranging from 0.4 to 2.3 m/s (mean: 1.02 ± 0.45 m/s SD). Density estimates, defined as the number of individuals per 100-m² sampled, varied from 0.1 to 2.8 individuals (mean: 0.4 ± 0.79 individuals SD) during the project at positive sites. Our data showed that E. x-punctatus is still extant throughout the Rock River drainage and the mainstem Vermilion River (Wabash River drainage), and that this fish showed a strong attraction to high velocity areas over clean, rocky substrates.