The Yellowcheek darter (YCD), Nothonotus moorei (Robison and Buchanan 2020), is endemic to the headwater tributaries (a.k.a. ‘forks’) of Little Red River system (South Fork, SF; Middle Fork, MF; Archey Fork, AF; and Beech Fork, BF) in north central Arkansas. Large portions of critical stream habitat in each stream fork were inundated in 1964 with the construction of Greers Ferry Dam, and the YCD is now restricted to relatively short, free-flowing stretches of each fork upstream of the dam. YCD were once reported as the most abundant riffle species in these headwater tributaries (Robison and Harp 1981), however, multiple status surveys and collection efforts in the decades since dam construction have documented a general decline in YCD abundance across each fork (Wine 2004; Wine et al. 2008). Due to its limited range, declining abundance, and multiple anthropogenic threats (e.g., land use changes, hydrologic alteration, habitat degradation), the YCD was federally listed as an endangered species in 2011. During the spring of 2018, a study was conducted by the U.S. Geological Survey, in cooperation with U.S. Fish and Wildlife Service, to assess YCD abundance (i.e., density) in relation to stream habitat characteristics within the four headwater forks of the Little Red River. Overall, we found that YCD had high site occupancy and similar, or relatively higher, densities than those reported in past studies. YCD densities were most strongly related to substrate embeddedness, but substrate size and stream velocity were also shown to be important variables for YCD occupancy and density in this study, as in others. However, given history of general decline over time and specialized habitat requirements of YCD, habitat degradation and changes in hydrology pose critical threats to YCD and should continue to be monitored over time. References: Raney, E.C., and R.D. Suttkus. 1964. Etheostoma moorei, a new darter of the subgenus Nothonotus from the White River system, Arkansas. Copeia 1964(1):130–139. Robison, H. W., & Buchanan, T. M. (2020). Fishes of Arkansas. University of Arkansas Press. Robison, H.W., and G.L. Harp. 1981. A study of four endemic Arkansas threatened fishes. Final report. U.S. Fish and Wildlife Service, Office of Endangered Species, Project E-1-3. Wine M. 2004. Current status of Etheostoma moorei (Raney and Suttkus) with emphasis on population sizes, distributions and reproductive habitat requirement. M.Sc. Thesis. Arkansas State University, Jonesboro, AR. 82 pp. Wine, M.S., M.R. Weston, and R.L. Johnson. 2008. Density dynamics of a threatened species of darter at spatial and temporal scales. Southeastern Naturalist 7(4):665–678.