Redband Trout (Oncorhynchus mykiss gairdneri) Population and Stream Habitat Surveys in Western Owyhee County, Idaho

Redband trout (Oncorhynchus mykiss gairdnen) were captured in twelve of the fourteen stream segments sampled in 1996. Stream segments were sampled on: Jordan, McBride, Cow, Pickett, North Fork Castle, Rock, Josephine, Big Boulder, Juniper, Cabin, South Mountain, and South Fork Boulder Creeks and the North Fork Owyhee River. Six of those sites had been previously sampled by BLM. Five of the resampled sites contained more redbands than were captured in previous sampling. Densities of trout greater than 100 mm in length at all sites ranged from Oto 41.5 trout /100 m2.

Habitat data were also collected on the sampled stream segments. Data collected included mean depth and width, percent of stream gradient, and percent composition of substrate. Measurements of bank stability, percent of stream shading, and available trout habitat were collected.

Water quality measurements of temperature, pH, conductivity, hardness, and alkalinity were all within acceptable ranges for trout survival. Recording thermographs were placed in seven Owyhee County streams, two thermographs recorded water temperatures consistently greater than 25 C.