American River Bull Trout Population

Overview

The American River originates in the William O. Douglas Wilderness Area and flows unimpeded for over 25 miles before converging with the Bumping River about 3.5 miles upstream of the latter’s convergence with the Little Naches River. For much of its length it is bordered by wilderness; however, SR 410 runs parallel to the river for a significant portion. The American River is fed by numerous tributary streams, three of the most significant being Union, Kettle, and Timber creeks. In addition to supporting bull trout, the American River is the most productive spring chinook spawning stream in the Naches River watershed. The American River bull trout population spawns in the mainstem, Union Creek, and Kettle Creek. The American River from RM 5.4 to the Mesatchee Creek Trail Crossing is closed to fishing from July 16th to September 15th each year to protect bull trout during their migration and spawning season.

Population Information

Population Distribution and Life History

The American River supports what is believed to be a single local population of bull trout that displays a fluvial life history type; there may be a resident component as well but this has not been confirmed. The known spawning area for the American River bull trout population includes the American River beginning just below where Kettle Creek enters the stream (~RM 9) and extending about 8.5 miles upstream (Figure XX). It also includes Union Creek, which enters the river at RM 11.5, and the lower reaches of Kettle Creek.

Juvenile bull trout most likely rear throughout the length of the river but presumably most remain within the spawning areas. Adult FMO habitat includes the Bumping, Little Naches, and mainstem Naches rivers. An unknown but assumed small number of adult bull trout evidently migrate up the Tieton River as well (see Population Monitoring below). Adults migrate upstream on the Naches River throughout the summer and into the American River in August.

Population Genetics

The American River population, while genetically distinct from all other populations, clustered with the other Naches River fluvial populations, indicating some degree of gene flow. Juvenile samples for the genetics baseline were collected in spawning and rearing areas, and adults were collected in a box trap after spawning during the radio telemetry studies in Union Creek (Mizell and Anderson 2010). Samples from the American River and Union Creek were run separately to determine whether bull trout spawning there were genetically distinct from one another and they were found to be genetically identical (Reiss 2003; Hawkins and Von Bargen 2007). Kettle Creek was not sampled separately; it is believed to be part of the same population group because of its proximity to the other spawning locations and relatively small number of redds.

Population Monitoring

The USFWS first documented the presence of bull trout (although they called them Dolly Varden) in the American River during habitat and fish barrier surveys conducted during 1935 and 1936 (McIntosh 1990). The population was not investigated again until WDFW captured several bull trout during electroshocking surveys in 1978 and 1985 (Washington Dept of Game 1978; WDFW 1985). Returning to conduct presence/absence electroshocking surveys in 1993, they reconfirmed the presence of bull trout in the American River and also documented the species’ presence in Union, Timber, and Kettle creeks (Anderson 1993b). Also present were cutthroat trout and brook trout. In 1993 The Forest Service also caught juvenile bull trout in minnow traps in Timber, Kettle and Union creeks (USFS 1993b). As mentioned above, annual spawning surveys have been conducted since 1996.

Mizell and Anderson (2010) investigated the migratory behavior of bull trout in the Naches River and tributaries. Bull trout that spawn in the American River and tributaries overwinter in the Naches River, generally downstream from Rattlesnake Creek. Their presence staging in pools in the American from Union Creek to the mouth in early fall has been documented on numerous occasions. The study revealed that adult bull trout leave the American River immediately after spawning, with some spending a short time in the Bumping River before moving downstream into the Naches River to overwinter.

In 2005, a hydroelectric project was constructed on Tieton Dam, at the head of the Tieton River. Thirty seven bull trout were captured in the stilling basin directly below Tieton Dam during a fish salvage effort (Ackerman 2005). Genetic samples were collected from these fish, and six were genetically assigned to the American River population (Small et al. 2009).

Redd Surveys

American River Redd Counts Through 2024

The American River population spawns primarily during the month of September. Complete redd surveys have been conducted for this population since 1996 in two American River index reaches and in Kettle and Union creeks. The lower mainstem index reach covers 0.4 mile below the Union Creek confluence, and the upper covers 2.8 miles at the upstream end of the known spawning area. The length of the reaches surveyed in Kettle and Union creeks are 0.7 and 0.4 miles, respectively. Both reaches begin at the mouth of the creek and end at natural fish passage barriers. Annual redd counts for the American River bull trout population has remained relatively stable over the period of record (Figure X).

Other Distribution Data (eDNA, etc.)

As part of the Range Wide Bull Trout eDNA project, Mid-Columbia Fisheries collected eDNA samples in parts of the Little Naches watershed in 2017 to determine if there was evidence of a spawning population. The results showed a few low-concentration "positive" sites. After discussion with USFWS bull trout researchers, it was determined that another round of eDNA should be collected to confirm presence or absence. WDFW conducted a demographic survey in 2024 and re-sampled eDNA in the middle and North forks of the Little Naches river. No bull trout were observed during demographic surveys and no bull trout DNA was detected. It is unlikely there is a spawning population (other than Crow Creek) in the Little Naches system.

Population Status and Trend

The USFWS (1998) did not consider the American River population singularly. The agency considered the Naches River “subpopulation” (i.e., all three Naches River fluvial populations) to be depressed with an unknown trend. WDFW similarly lumps the Naches fluvial populations and rates the status of this stock as critical (WDFW 2004).

Habitat

Habitat Overview

The American River is a relatively high elevation river ranging from 2,750 feet to 3,600 feet. The known spawning area for bull trout is located along the boundary of the Norse Peak Wilderness Area to the north and the William O. Douglas Wilderness Area to the south. As was noted above this is also considered the primary juvenile rearing area. SR 410 parallels the river along this boundary, but the road’s effects on floodplain confinement are minimal as the river is naturally confined for the most part (USFS 1998 - Anyone have reference?). Habitat conditions in the American River were described in detail in the Limiting Factors Analysis (Haring 2001). Good to excellent conditions were noted for channel condition, substrate condition, riparian condition, water quality, and water quantity. Concerning riparian condition, some degradation leading to bank erosion was noted in areas where Forest Service campgrounds (Pleasant Valley, Hells Crossing, Lodgepole) are located. Spawning and rearing habitat in the two important tributaries (Union and Kettle creeks) were not addressed in the analysis but are considered to be highly suitable by local bull trout experts.

The Naches River is believed to provide the primary FMO habitat for American River adult and subadult bull trout but it is probable that habitat in the Bumping and Little Naches rivers is also used to some extent. Habitat conditions in the Naches and Little Naches rivers were described previously (see Naches Fluvial Populations FMO Habitat Overview; Crow Creek Habitat Overview). Below Bumping Dam the river flows for over 16 miles through National Forest land and is in close proximity to the William O. Douglas Wilderness Area. Like the American River, a road parallels the Bumping for much of its length. Four Forest Service campgrounds are located along its banks as well as a numerous private residences. None of this recreational development is believed to have a significant impact on FMO habitat quality in the Bumping River.

Climate Change impact on Habitat

From David: I suggest we add a paragraph describing the anticipated changes to habitat in the coming decades.

For example in the SSA, cumulative distance of streams with mean August stream temperatures ≤13⁰C for each core area was analyzed, following Dunham et al 2004 and Isaak 2015. Can we use NorWest/Climate shield data to do this at the local population scale? Is this too heavy a lift?

Habitat Monitoring

Field Habitat Surveys

The Forest Service completed habitat surveys on the American River in 1992 (22.4 miles) and again in 2001 (9.8 miles) using Hankin and Reeves protocol (USFS 2003c). The 2001 data were used in a thesis project comparing the American and Little Naches rivers (Muir 2003). Kettle Creek (1.5 miles) was surveyed in 1993 (USFS 2003c). In all of these surveys, data were collected on pool/riffle frequency, riparian and channel condition, substrate, LWD, and temperature.

In addition, the Forest Service completed a watershed analysis of the American River system in 1998. Banish (2003) measured bull trout microhabitat and mesohabitat in 10 Eastern Washington and Oregon streams. Banish conducted day and night snorkeling in Kettle Creek; however, he pooled his data and did not report results for individual steams.

Stream Temperature Data

In 2001, the Forest Service contracted aerial thermal infrared remote sensing surveys on the American River from the mouth to the confluence with Rainier Fork (Watershed Sciences 2002). Accuracy of temperatures was confirmed with instream sensors. The flights were completed in early September and stream temperatures ranged from 8.8-12.8 °C. Kettle Creek and Union Creek were measured at their confluences with the American River, and the temperatures were 10.1 °C and 9.7 °C respectively.

Temperature monitoring in the American River system is primarily from Forest Service thermographs deployed during the summer low flow period. One thermograph on the American River at the USGS gage was deployed in most years from 1991-2007. Other thermographs were deployed in five other locations on the American River and on associated tributaries, including Union and Kettle creeks, during the years from 1995-2007, although not consistently (USFS 2011a). Temperature data since 2007 is a monitoring gap.

Threats

Connectivity

Fish Passage Barriers

Threat Severity:

Check / update FPDSI

Entrainment

Threat Severity:

Dams? Irrigation?

Dewatering due to flow management

Threat Severity:

Land-use Issues

Forestry

Threat Severity:

Agriculture and Grazing

Threat Severity:

Recreation

Threat Severity:

Roads and Development

Threat Rating:

Mining

Threat Severity:

Ecological Interactions

Brook Trout

Threat Severity:

Other Invasive Species

Threat Severity:

Diminished Prey Base

Threat Severity:

Disease

Threat Severity:

Water Quantity and Quality

Flow issues/dewatering

Threat severity:

Current and modeled future temperature conditions

Threat Severity:

(iFrame of NORWEST results?) Quick analysis of trends since USFWS started monitoring?

Fisheries Impacts

Angling Regulations/Fisheries Use/Poaching (Recreational)

Threat Severity:

Fisheries Management/Monitoring (Research)

Threat Severity:

Other Threats

Low Population Resiliency

Threat Severity:

Extrinsic Vs. Intrinsic small population threats?

Climate Change

as one over-arching threat? Or certain threats may be exacerbated by climate change?

Summary of Primary Limiting Factors

(Look at threat summary table format and Teanaway example)

Tied to stuff from SSA

With a geometric mean of <50 redds annually (see Appendix B) low abundance is identified as a moderate threat but this population is not considered a candidate for supplementation due to a stable population trend. The next highest threats to this population are those of unknown severity. Likely significant are angling, prey base, and recreation. The American River, Union Creek, and Kettle Creek spawning reaches are closed to fishing but rearing and FMO areas downstream are currently open. Illegal and/or incidental catch of bull trout can cause direct mortality of adults and reduce overall population productivity. There are dispersed and developed campsites as well as trails and trailheads along the spawning and rearing reaches on the American River and Union Creek. These may affect the bull trout population via habitat degradation and direct harassment. Introduced brook trout are present within the spawning area, but no hybrids have been documented thus far during genetic sampling.

Altered flows, development, transportation, and forest management issues are present within the population area (spawning and rearing or FMO) but are not considered significant threats. The following threats are absent: agriculture, dewatering, entrainment, grazing, limited extent of habitat, mining, and passage barriers.

Recovery Strategy

Population-level Recovery Strategy

(High-level discussion of priority needs)

This population has been identified as a “Protection” population with a priority for continuation of population monitoring but with limited restoration actions recommended. Although spawning and rearing occurs outside of the wilderness, the American River and associated spawning tributaries (Union and Kettle creeks) have generally excellent habitat. Recreation sites along the river are the source of some habitat degradation and actions to minimize and prevent riparian damage are a moderate priority. Outreach is a priority in order to document angling pressures and to educate anglers and recreationists throughout the watershed. Although restoration actions implemented in the Naches River would benefit this population, current conditions are not thought to be limiting. The Broad Scale Actions that apply to the American River population include: Restore Healthy Salmon Populations and Passage at Major Storage Dams (Bumping and Rimrock). Revitalizing salmon and steelhead runs in the Yakima Basin would significantly improve the prey base for all bull trout life stages. Providing passage at the two storage dams in the Naches subbasin would benefit the Naches River fluvial bull trout populations in general.

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Actions

Completed Bull Trout Recovery Actions

• Approximately 2.8 miles of dispersed camp roads were closed between 2003 and 2006.
• Between Pinus Creek and Timber Creek over 27 acres of riparian/valley floor acres habitat have been protected with 6.5 acres replanted with native grass and shrubs between 2003 and 2006.
• Fish harassment issues at Forest Service stream-adjacent campgrounds (Lodgepole, Hells Crossing, and Pleasant Valley) have been addressed through public contact and interpretive signing between 2003 and 2006.
• Fishing regulations have been implemented to protect American River bull trout (see Appendix F).

Recommended Actions

Implementation Monitoring of Completed and Recommended Actions

• Forest Service to continue monitoring of restored riparian areas to ensure compliance with camping exclusions.

Relevant Multiple Population Actions

• Multiple Populations #1: Outreach on bull trout conservation issues (landowners, recreationists, anglers, school groups, and others)
• Multiple Populations #6: Floodplain acquisition/easements along the mainstem Naches River to benefit FMO habitat quality.
• Multiple Populations #5: Carcass analog placement if pilot studies demonstrate success.
• Multiple Populations #2: Continue redd surveys within the established index areas to monitor long-term abundance trends.
• Multiple Populations #3: Continue temperature monitoring.

XXX River Actions

• American River #1: Protect and restore stream banks by relocating and restoring campsites.

Actions in the Yakima Steelhead Recovery Plan that benefit this population

Naches River Action #5: Restore lower Naches River floodplain

Naches River Action #7: Protect habitats in Naches River mainstem above Tieton River confluence

Naches River Action #9: Provide passage at Bumping Lake Dam

Naches River Action #13: Reduce dispersed recreation impacts in key tributaries

Update Notes

2012 BTAP text copied into Yakipedia and edited to match new format in December 2024 by Aimee Taylor. ADD LINK TO 2012 BTAP pdf placemark

Additional edits proposed by Alex Conley, Aimee Taylor and XXXX populations small group. Reviewed, and updated and approved by BTWG in XXXXX

Use this space for specific detail on out of cycle updates: