Rattlesnake Creek Bull Trout Population

Overview

Rattlesnake Creek is a right-bank tributary of the Naches River, which originates in the William O. Douglas Wilderness Area and is approximately 20 miles in length from its origin to its confluence with the Naches River at RM 28. The north fork is much shorter and appears impassable for fish a short distance upstream of the confluence of the two forks. Several small tributaries enter the south fork along its course, including Little Wildcat, Shell, Dog and Hindoo creeks. Little Rattlesnake Creek enters well below the forks about a mile above the mouth of Rattlesnake Creek.

Population Information

Population Distribution and Life History

Rattlesnake Creek supports a single local population of bull trout, which displays a fluvial life history type; a resident component may exist as well but this has not been confirmed. The primary spawning area for this population is located in the south fork above the wilderness boundary at RM 14 and extends about seven miles upstream; it includes Little Wildcat and Shell creeks (Figure 5). Juvenile bull trout are assumed to rear in Rattlesnake Creek all the way down to the mouth; adult FMO habitat is primarily the Naches River below the Rattlesnake confluence but some adults also utilize FMO habitat upstream (Mizell and Anderson 2010). An unknown but assumed small number of adult bull trout evidently migrate up the Tieton River and the mainstem Yakima River as well (see Population Monitoring below). Adult bull trout migrate into Rattlesnake Creek in late June and July and are in close proximity to their spawning grounds by mid-August.

insert map of Rattlesnake Creek subwatershed

Natural Barriers limiting distribution

Anyone know of any barriers? Mainstem or tributaries

Population Genetics

Results of genetic analyses show this population is genetically distinct from all other Yakima Basin populations but did cluster with the other Naches River fluvial populations, indicating some degree of gene flow either currently or historically (Reiss 2003; Small et al. 2009). Juvenile samples for the genetic baseline were collected in spawning and rearing areas above the wilderness boundary on Rattlesnake Creek, and adults were collected in a box trap post-spawning during the radio telemetry studies (Mizell and Anderson 2010). No samples were collected in the smaller tributaries.

Population Monitoring

The USFWS first documented the presence of bull trout (although they called them Dolly Varden) during habitat and fish barrier surveys conducted during 1935-1936 (McIntosh 1990). A survey by the Washington Department of Game Fisheries Research Team in 1975 also documented bull trout (Dolly Varden) (Washington Dept of Game 1975). The population was not investigated again until WDFW captured several juvenile bull trout in Rattlesnake Creek during electroshocking surveys (Anderson 1991). Exploratory spawning surveys were first conducted in 1994 with complete surveys initiated in 1996. In 2001 juvenile bull trout were captured in the creek during snorkel surveys conducted in association with the collection of genetic samples (Reiss 2003).

Mizell and Anderson (2010) investigated the migratory behavior of bull trout in the Naches River and its tributaries. They reported on migration timing and overwintering habitat. In October after spawning, adults migrate back to the Naches River to over-winter. Although not observed during this radio telemetry study, a few Rattlesnake Creek adults appear to make their way up the Tieton River. Small et al. (2009) reported that six of 34 adult bull trout captured in the stilling basin directly below Tieton dam, most during a fish salvage operation in December 2005, genetically assigned to the Rattlesnake Creek population. Evidence that Naches River fluvial bull trout may use FMO habitat in the mainstem Yakima River comes from a single bull trout that was sampled at Roza Dam in 2005, which also genetically assigned to the American River population (see Appendix C).

Attempting to determine the complete distribution of bull trout in the Rattlesnake Creek watershed, WDFW also conducted electroshocking surveys on the North Fork Rattlesnake Creek and Little Rattlesnake Creek in 1990 and 1994, finding no bull trout (WDFW 1990). In addition the Forest Service completed night snorkel surveys on this tributary in 2002 using the bull trout presence/absence protocols developed by Peterson et al. (2002). No bull trout were found during these surveys (USFS 2002). Technicians with YN Coho Program documented subadult bull trout in the lower portion of Little Rattlesnake Creek in 2006 and 2011 (T. Newsome, YN, pers comm.). Due to the absence of bull trout found in the previous surveys, it is assumed this fish belonged to the Rattlesnake Creek population.

Redd Surveys

The Rattlesnake Creek population spawns primarily during the month of September. Complete redd surveys have been conducted for this population since 1996 in an index area beginning about 2.8 river miles above the wilderness boundary and extending upstream 7.1 miles; also surveyed are 0.1 mile of Shell Creek and 0.5 mile of Little Wildcat Creek. This index area is believed to cover the entirety of the spawning habitat currently utilized. Annual redd counts have been highly variable with counts ranging from 13 to 69 (Figure 4).

Insert redd graph

Population Status and Trend

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

Habitat

Habitat Overview

Rattlesnake Creek is a high gradient stream with elevations ranging from 1,960 feet at its mouth to over 3,500 feet at the upstream extent of the spawning area. Approximately 56% of the watershed, including the entire portion where bull trout spawn, is in the wilderness. Habitat conditions in the spawning area are excellent considering all rating parameters—channel condition (pool frequency and depth, LWD presence); substrate condition (suitable spawning gravels, sedimentation); riparian condition; water quality (temperature, chemicals/minerals); and water quantity (Haring 2001). Bull trout juveniles rear above and below the wilderness boundary. Below the boundary the creek flows primarily through National Forest land with the exception of some private holdings in the lower mile of the stream corridor. There are a small number of private residences (less than 10) located on Forest Service land 5-6 miles upstream of the mouth and several on the private land nearer the mouth. The upstream residences are not believed to significantly affect habitat quality in the creek. Haring (2001) described habitat condition in the non-wilderness section of Rattlesnake Creek as good above the Little Rattlesnake Creek confluence (RM 1.0). Below this point, the channel has been constrained by a bridge and by diversion structures, limiting the area available for sediment deposition in the floodplain and resulting in chronic aggradation at the confluence with the Naches River. There have been concerns in the past that in dry years adult bull trout migration into the creek may be impeded. The span of the bridge was lengthened in 2008, which should, over time, reduce aggradation; the most significant diversion was removed in 2009.

Climate Change impact on Habitat

THIS SECTION TO BE UPDATED AS ZAC COMPLETES TEMPERATURE MODELING

Habitat Monitoring

Field Habitat Surveys

The Forest Service has conducted habitat surveys on Rattlesnake Creek and its tributaries using a Hankin and Reeves protocol (Hankin and Reeves 1988). On the mainstem Rattlesnake Creek, 7.2 miles were surveyed in 1996, Little Rattlesnake Creek survey was completed in 2002, and all tributaries were surveyed in 1994, including Little Wildcat and Shell creeks (USFS 2003c). During these surveys, data were collected on pool/riffle frequency, riparian and channel condition, substrate, LWD, and temperature. Sediment samples were collected and analyzed in a reach of Rattlesnake Creek below the wilderness boundary in 1997 and 2002 (Matthews 2006). In 2009, the Forest Service completed a road condition survey on major roads within the Rattlesnake drainage (USFS 2009).

Stream Temperature Data

Temperature monitoring via thermographs deployed during the summer low flow period has been sporadic, but some degree of monitoring occurred in 11 out of 17 years between 1991 and 2007 (USFS 2011a). Monitoring sites were located in Rattlesnake, NF Rattlesnake and Little Rattlesnake creeks. Collection of temperature data since 2007 is a monitoring gap.

Threats

Connectivity

Fish Passage Barriers

Threat Severity:

Entrainment

Threat Severity:

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 Severity:

Mining

Threat Severity:

Ecological Interactions

Brook Trout

Threat Severity:

Other Invasive Species

Threat Severity:

Diminished Prey Base

Threat Severity:

noted as priority threat in 2012

Disease

Threat Severity:

Water Quantity and Quality

Flow issues/dewatering

Threat Severity:

Current and modeled future temperature conditions

Threat Severity:

Fisheries Impacts

Angling Regulations/Fisheries Use/Poaching (Recreational)

Threat Severity:

Management/Monitoring (Research)

Threat Severity:

Other Threats

Low Population Resiliency

Climate Change

Summary of Primary Limiting Factors and Threats

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 threat to this population (prey base) is unknown but believed to be of significant severity. Currently steelhead, spring chinook, and coho spawn in the lower reaches of Rattlesnake Creek but at much lower numbers than historically. Angling is another potential threat to this population. However, because of difficult recreational access, this is not likely a limiting factor. The potential for entrainment into irrigation diversions is present in the lower reaches, and the impact to migrating or rearing juvenile bull trout is unknown.

Brook trout (an introduced species) are present in lower reaches of Rattlesnake Creek and in the Naches River, but no evidence of hybridization was found during genetic sampling. Dewatering, altered flows, development, forest management issues, roads, passage barriers (potential) and recreational impacts are all present in the FMO habitat and lower rearing reaches of Rattlesnake Creek but are not believed to be significantly impacting the population. There is a sheep grazing allotment in the Rattlesnake drainage but this has never been documented to damage riparian areas. Altered flows have been an issue in the past in lower Rattlesnake Creek but recent improvements appear to have adequately mitigated this threat. Threats that are not present for this population include: agriculture, limited extent of habitat, and mining.

Recovery Strategy

Population-level Recovery Strategy

This population has been identified as a “Protection” population with a priority for continued population monitoring but with limited restoration actions recommended. Spawning and rearing occurs in the wilderness where no threats are present and threats are limited in the reach outside of the wilderness where rearing also occurs. In the lower reaches of Rattlesnake Creek and in the Naches River, implementing restoration actions would benefit this population. Current conditions in these reaches, however, are not thought to be limiting. Outreach is a priority in order to document angling pressures and educate anglers, recreationists, and landowners throughout the watershed. The Broad Scale Actions that apply to the Rattlesnake Creek 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.

---

Actions

Future link/ iframe to PowerApp will go in this section.

Completed Bull Trout Recovery Actions

• The Boyd Brown diversion (associated with altered flows) near the Nile Road Bridge was removed in 2009.

·      WDFW in 2001 manually modified multiple channels at the mouth of Rattlesnake Creek into a single channel to provide fish passage in 2001 drought year.

• One unscreened (non-compliant) pump diversion was screened in 2011 by the North Yakima Conservation District.
• The Nile Road Bridge over Rattlesnake Creek was replaced in 2008.
• Fishing regulations have been implemented to protect bull trout in Rattlesnake Creek (see Appendix F).

Recommended Actions

Relevant Multiple Population Actions

• Multiple Populations #1: Outreach on bull trout conservation issues (landowners, recreationists, anglers, school groups, and others).
• Multiple Populations #5: Carcass analog placement if pilot studies demonstrate success.

• Multiple Populations #6: Floodplain acquisition/easements along the mainstem Naches River to benefit FMO habitat quality.

• Multiple Populations #2: Continue redd surveys within the established index areas to monitor long-term abundance trends.

• Multiple Populations #3: Continue temperature monitoring.

Rattlesnake Creek Actions

Rattlesnake #1: Monitor effectiveness of fish screens on irrigation diversions

Actions in the Yakima Steelhead Recovery Plan that benefit this population

(Yakima Basin Fish & Wildlife Recovery Board 2009)

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 #17: Increase instream flows in lower Rattlesnake Creek

Naches River Action #18: Improve sediment transport at Rattlesnake Creek/Naches River confluence

Update Notes

2012 BTAP text copied into Yakipedia and edited to match new format in February 2025 by Aimee Taylor. ADD LINK TO 2012 BTAP pdf placemark

Additional edits proposed by Alex Conley, Aimee Taylor and XXXXXXX small group. Reviewed, and updated and approved by BTWG in XXXXXXXXXXXXX

Specific detail on out of cycle updates: