Redband Trout Population and Habitat Surveys in Southern Owyhee County, Idaho

Seventeen stream segments were sampled by electrofishing for redband trout (Oncorhynchus mykiss gairdneri) in stream drainages in southern Owyhee County, Idaho. Stream surveys were conducted on the South Fork Owyhee, Little Owyhee, Owyhee, West Fork Bruneau, and Jarbidge Rivers and Marys, Blue, Little Blue, Shoofly, and Sheep Creeks. Seven of the seventeen stream segments sampled contained redband trout. Redband trout densities for all size classes of trout ranged from 0.08 to 1.82 trout/100m2. Habitat data were also collected on the sampled stream segments. Data collected included stream depth, stream width, percent of stream gradient, and percent composition of substrate. Measurements of bank stability, percent of stream shading, and available trout habitat were also collected. Basic water quality parameters of water temperature, pH, conductivity, hardness and alkalinity were all within acceptable ranges for trout survival. Recording thermographs were placed in Jordan Creek from June until November, 1995. Maximum water temperature recorded was 24.6°C on July 16, 1995. It is recommended that redband trout surveys be continued to better define the distribution of the desert populations of redband trout.