Northern Prairie Wildlife Research Center
We collected Arkansas darters with dip-nets, because it is difficult to effectively seine or electrofish in the vegetated habitats occupied by this species. At each site, one to three people concentrated their sampling efforts in areas with rooted aquatic vegetation, filamentous algal mats, or overhanging vegetation and roots along the banks. Depending on the extent of suitable habitat, we expended 10 to 45 minutes of sampling effort (number of minutes × number of people sampling) at each location.
At most sites, we recorded the numbers of "adult" and "young" Arkansas darters, based on two general size classes noted in our samples. At localities with extensive habitat and where we captured Arkansas darters in virtually every dip-net sample, we recorded them as "numerous" (usually more than 100 individuals counted). We took no voucher specimens in consideration of the protected status of the species in Kansas and Oklahoma. We considered misidentification to be unlikely; the only other species of Etheostoma in the area is the distinctive orangethroat darter (Etheostoma spectabile).
We measured water temperature and specific conductance with a Hach 44600 Conductivity/TDS Meter at most sites where the Arkansas darter was sampled. In addition, we estimated canopy cover as a percentage of the width of the stream channel. We also noted substrate composition and types of aquatic vegetation or other submerged structures.