Salmon, Water & Wetlands: Bull Trout

The Bull trout (Salvelinus confluentus) are North America’s southernmost descendant of the arctic char subgroup of the salmon family. The species’ native range includes the northern portion of the northwest United States (Oregon, Washington, northern California, northern Nevada, western Montana, and Idaho) and extends upwards to Canada and Alaska. Bull trout are now extinct in California despite reintroduction efforts and were nationally listed as a threatened species under the federal Endangered Species Act in 1998.

Habitat RequirementsThe bull trout is a sensitive species that requires a cold and clean water habitat. It is thought of as an indicator species because of its stringent water quality requirements. Streams and rivers with healthy bull trout populations generally exhibit good water quality conditions and functioning ecosystems.  In order to maintain a healthy bull trout population a stream or river must have very cold water with a low level of fine sediment. Fine sediments can smother the eggs and fry during the incubation period, leading to a low percentage of survival to emergence. Bull trout fry (young fish) develop in a uniquely slow manner, making them susceptible to even small perturbations in water quality.

Bull Trout In Oregon — Currently, there are seventy bull trout populations in the Columbia Basin and nine populations in the Klamath Basin. Populations from twelve areas in Oregon are now considered extinct. Bull trout populations were historically present throughout the Willamette River system on the West side of the Cascades, including the Clackamas, Santiam, McKenzie and Willamette Rivers, but have since become significantly reduced in this region. The Oregon Department of Fish and Wildlife (ODFW) believes that the McKenzie River and its tributaries in and around the Willamette National Forest support the only self-sustaining population west of the Cascades in Oregon. The sub-population within the main stem of the McKenzie consists of migratory fish that spawn in two tributaries, Anderson and Olallie Creeks, and possibly a third, Sweetwater Creek. The Oregon Department of Fish and Wildlife have conducted surveys within the McKenzie system in an attempt to document the status of this subpopulation. Between September and December of 2000, ODFW identified 94 spawning redds. ODFW also conducted pool counts within the main stem of the McKenzie and identified only 18 fish in 2000, well below peak counts from 1994-95. ODFW has also collected similar information for the Roaring River, a tributary of the South Fork of the McKenzie, identifying 23 redds in 2000 and identifying 4 fish in pool counts, the lowest number ever recorded. (Draft ODFW 2000.)

The sharp drop in bull trout populations is a direct result of land management activities including dam building, forest management practices, livestock grazing, agriculture, water diversion, roads, and mining. These activities severely damage the habitat that bull trout need to survive.

ODFW Reintroduction Plan — ODFW, US Fish and Wildlife Service (USFWS) and the US Forest Service (USFS) considered the subpopulation in the Willamette functionally extinct as of 1990, the date of the last confirmed fish above Hills Creek Reservoir.In 1997, ODFW initiated a bull trout reintroduction program for the Middle Fork Willamette. ODFW concluded that the “Middle Fork Willamette bull trout will not continue to persist in the sub-basin without rehabilitation efforts” and that “the only way of holding onto the remaining genetic material was to provide a carrier for that material.” (ODFW 1997). With that goal in mind, ODFW began transplanting fry from the McKenzie into the Middle Fork in 1997. Between 1997 and 2000, ODFW transplanted a total of 6,441 fry into the Middle Fork system. ODFW has conducted limited monitoring efforts to determine the success of these reintroduction efforts, but it is likely that the population is still struggling.

Timber Sales and Bull Trout Survival — Given the fragile status of bull trout populations west of the Cascades, activities that will place stress on their habitat need to be avoided or implemented with extreme caution. However, the U.S. Forest Service and the U.S. Fish and Wildlife Service continue to contradict this knowledge by allowing destructive logging practices within the Willamette National Forest. The increased sediment and water temperature from logging makes it highly impossible for the ODFW’s reintroduction program, and the bull trout, to survive.  In 2003, Crag represented local conservation groups and secured an important victory by protecting the bull trout from old-growth timber sales planned by the U.S. Forest Service in the Upper Willamette and McKenzie River drainages.  These projects had been rubber stamped by the U.S. Fish and Widlife Service. Click here to learn more about this important case. (PDF 116kb).  Going forward, the Crag Law Center is working with fish conservation groups and local citizens to ensure that the existing habitat for the Bull Trout and other fish species is preserved and the degraded areas are restored.


Additional Bull Trout Links