Fish Monitoring: Deschutes River Basin Fish and Their Habitat Needs

The Columbia River Basin Redband Trout, Oncorhynchus mykiss gairdnerii,
in its native Deschutes River waters.

A primary species of concern, and one of the key indicators of overall health in the Deschutes watershed, is the native redband trout.  Redband trout were historically found in large numbers throughout the Deschutes River and its tributaries.  Today, Redband populations in the Upper Deschutes sub-basin are smaller than those in the lower sub-basin and are often fragmented.  Redband trout have been deleteriously affected by the stocking of hatchery rainbow trout, low seasonal stream flows, and degraded river habitats.

The Upper Deschutes watershed provides a rare opportunity to reconnect redband populations.  Currently, fragmented but healthy populations of redbands reside in headwater streams, while redband populations in the mainstem Deschutes River are severely reduced.  If habitat and flow conditions are not sufficient to reconnect the headwaters and mainstem populations, scientists believe that redband populations could become isolated and at risk for maintaining genetic integrity of the species (Rieman and McIntyre 1993).

While redband trout are the focal species for this Home Rivers Initiative, projects undertaken to protect and restore redband trout habitat will also help other fish species throughout the watershed. The Upper Deschutes Basin holds two "depressed" populations of bull trout which are listed as "Threatened" under the ESA. These two populations stand to benefit from improvements to water temperature, water quality, and river habitat in connection with numerous restoration efforts. The upper Deschutes watershed was once home to anadromous salmon and steelhead, but access to the upper basin has been blocked since 1968 when the fish passage systems installed with the dams in the Pelton-Round Butte complex failed. The Federal Energy Regulatory Commission’s renewal of the operating license of the Pelton-Round Butte complex, signed in 2004, includes a requirement to attempt to re-establish salmon and steelhead spawning populations to their historic habitat above the dams. The reintroduction effort is without question a grand experiment, and while determining the need, goals, and strategies for restoration in the Upper Deschutes drainage should not hinge on the success or failure to restore naturally spawning populations of steelhead or salmon, its implications for this program are important. Should reintroduction efforts succeed, anadromous fish will find improved spawning and rearing habitat as a result of redband and other trout restoration projects.

The Fall River provides a great example of the cold, spring-fed streams of the west side of the Deschutes Basin coming off the Cascade Mountains and dwindling glaciers. The diversity of cold and warming waters provide for outstanding stretches of habitat for native Bull Trout and other fish species.