Cooperative Fish and Wildlife Research Units Program: Colorado
Education, Research and Technical Assistance for Managing Our Natural Resources

Water temperature is a critical abiotic factor that contributes to larval fish survival. Many fish species are poorly adapted to survive water temperatures that lie outside historic annual or seasonal variability. To properly manage the three species it is essential to understand their thermal tolerances. Bluehead Sucker, Flannelmouth Sucker, and Roundtail Chub, hereinafter referred to as the three species, intermittent and ephemeral streams for refugia from high main-stem flows, foraging, and for spawning and larval rearing. A review of these three species in the Colorado River basin suggest that they occupy 50% or less of their historic ranges, and current populations are still declining. The declines are thought to be in part caused by changing stream water temperatures. These data will be used to address management concerns regarding the three species and stream water temperature.