Great Basin Naturalist


The relict dace, Relictus solitarius, represents the only genus and species of fish native to Ruby Butte, Goshute, and Steptoe valleys in northeastern Nevada. In their natural habitats temperature ranges 0–25 C and salinity 175–1,158 mg/liter. The upper median thermal tolerance limit (96-hr TL50) of Butte Valley relict dace was 30.6 C when acclimated at 18–20 C. Relict dace tolerated total dissolved solids (TDS) of 11,043 mg/liter with no mortality during 96-hr exposures, but experienced 100 percent mortality at concentrations of 15,759 mg/liter with a mean resistance time of 23 hours. Tolerance of relict dace to 30 C was lowered as TDS was increased from 2,845 to 5,652 mg/liter. The Butte Valley fish were slightly more resistant to elevated salinities than the Goshute Valley sample, and conversely the Goshute Valley sample may be slightly more resistant to elevated temperature.