Research on northeast Oregon’s Catherine Creek is helping to focus habitat restoration efforts needed to recover the creek’s spring chinook, steelhead and bull trout populations, which are all listed under the federal Endangered Species Act.
Catherine Creek is part of the Grande Ronde River system, which flows through Oregon’s far northeastern corner before crossing into southeastern Washington and eventually joining the Snake River. The stream originates in the Eagle Cap Wilderness Area of the Wallowa Mountains.
Catherine Creek spring chinook and steelhead belong to larger populations of ESA-listed chinook salmon and steelhead that spawn and rear in the Snake River basin. The vast Snake River drainage extends over parts of Oregon, Idaho and Washington, and is the Columbia River’s largest tributary.
Efforts directed under the ESA to recover Snake River spring chinook target Catherine Creek as one of the highest priority areas for habitat restoration. Catherine Creek also provides critical habitat for summer steelhead and bull trout.
Most of the current research in Catherine Creek centers on gaining information to determine where and how best to restore habitat conditions to improve the creek’s severely depressed spring chinook population.
The research focuses on physical conditions and fish movement in a 55-mile reach of Catherine Creek that provides important habitat for spring chinook and steelhead. The study reach extends upstream from Catherine Creek’s confluence with the Grande Ronde River to where the North and South Forks of Catherine Creek join the stream.
Key participants in the research efforts include the Bureau of Reclamation, Oregon Department of Fish and Wildlife, Bonneville Power Administration, Grande Ronde Model Watershed, and Union Soil and Water Conservation District.
According to Jeff McLaughlin, subbasin coordinator with the Bureau of Reclamation’s Columbia/Snake River Salmon Recovery office, the research is providing information on where fish spend their time and what types of habitat they need.
The new scientific information is helping managers identify high priority project sites and frame restoration efforts so they can use limited resources wisely, he said. The information is a great tool for working with landowners, McLaughlin said, because it shows where fish are in creeks that borders their property.
It allows landowners and managers to design individual projects that will best address the factors limiting the fish, he said.
Investigations of juvenile spring chinook movement and “microhabitat” use are playing a critical role in the research assessment. Before the research began, fish managers knew the 55-mile reach served as important habitat for chinook and steelhead, but did not know which areas in the reach received the most fish use.
The investigations, conducted by ODFW’s northeast Oregon fish research team, are providing this information.
ODFW’s investigations show that a large number of spring chinook rear in the middle reach of Catherine Creek, especially during winter months. The investigations suggest that winter rearing habitat quality in this reach of Catherine Creek may be a particularly important factor limiting spring chinook smolt production in the creek.
About 80 percent of juvenile spring chinook in Catherine Creek are considered early migrants, and survival of these early migrants is typically lower than for other such populations in the Grande Ronde basin. Catherine Creek’s early migrant spring chinook leave natal upstream habitats above the town of Union in the fall and migrate to downstream areas where they spend the winter.
The creek’s other juvenile spring chinook, the late migrants, stay in natal upstream rearing areas of Catherine Creek through the winter. In the spring, both the early and late groups of spring chinook leave Catherine Creek and begin their migration toward the Pacific Ocean. Approximately one-third of Catherine Creek’s steelhead population also overwinters in downstream areas and are considered early migrants.
Since fall 2009, ODFW fish biologists have followed the early migrant spring chinook using radiotelemetry techniques. The technology has allowed them to identify primary overwintering locations. The biologist not only track tagged juvenile chinook, they also collect data on microhabitat use, including reach depth, velocity, dominant substrate, cover and distance from stream bank.
According to Scott Favrot, an ODFW fish biologist working on the project, results from the radiotelemetry studies show that many of the early migrant juvenile chinook overwinter in areas of Catherine Creek between Mill Creek and the town of Union. The fish seek overwintering habitats containing deep pools and slow currents near cover.
Favrot says that, “preliminary results from radio tagging suggest that most of the fish survive through the winter. The majority of fish mortality is occurring in this reach of Catherine Creek during the spring outmigration.”
He says, starting this year, they will conduct additional research during the spring to determine why the fish are dying.
A tributary habitat assessment by the Bureau of Reclamation is providing additional information to concentrate habitat restoration efforts on Catherine Creek.
An interdisciplinary team of experts in fisheries, vegetation and physical processes (hydraulics, hydrogeology, geomorphology and hydrology) are conducting the assessment studies. The studies are examining channel and floodplain processes that affect salmon habitat in the 55-mile reach. They focus on factors that could limit fish use of the habitat area, such as changes in hydrology, water quality, fluvial geomorphology, and stream hydraulics. They included groundwater thermo-profiling studies and fish habitat surveys.
Together, findings from the ODFW investigations and assessment studies indicate that improving habitat conditions in the lower 46 miles of Catherine Creek will provide the greatest benefits for spring chinook and steelhead. According to McLaughlin, improving habitat conditions in key overwintering areas near the town of Union will have an immediate impact on the fish.
Assessment findings on limiting factors for fish in the reaches of Catherine Creek suggest that habitat restoration focus on:
-- Improving habitat complexity and connectivity, especially pools;
-- Increasing large wood amounts and retention;
-- Improving riparian vegetative communities and functions;
-- Stabilizing stream banks;
-- Providing fish passage at diversions; and
-- Increasing summer flows.
Fish habitat managers are also using the information to target additional studies at a finer scale, including refocusing fish monitoring studies to get more data in areas where juvenile salmonids have high mortality.
Historically this reach of Catherine Creek provided important habitat for chinook spawning, incubation, rearing and outmigration.
Rearing and overwintering habitats were likely particularly abundant. The reach displayed complex habitats including large debris, substantial stream meandering, beaver complexes, diverse pools, and healthy riparian communities that created healthy rearing and overwintering conditions. Large-scale changes to the landscape and the creek altered these historic conditions and greatly reduced the complexity and availability of salmon habitat. The lower valley section experienced the most impact, followed by the middle valley section, and lastly the upper valley section.
Efforts to define and implement projects that will improve habitat conditions in Catherine Creek comply with direction identified under the Federal Columbia River Power System biological opinion. The BiOp calls for actions to protect and recover ESA-listed salmon and steelhead.
The current BiOp targets Catherine Creek as one of the highest priority areas for habitat restoration.
In February 2012, the Bureau released its final report describing the first phase in the assessment to identify channel and floodplain processes relevant to salmonid in Catherine Creek. The assessment gives resource managers and area stakeholders pertinent scientific information that will help them prioritize future work and fine-tuning individual projects. It also identifies data gaps that allow managers to target additional studies at a finer scale.
The Bureau is now conducting detailed follow-up assessments for several reaches, which are scheduled for release in 2012.