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 with Rattlesnake Creek. Several small tributaries enter Rattlesnake Creek 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. Rattlesnake Creek is open to fishing the Saturday before Memorial day through October 31st each year. The regulation is catch-and-release only for all trout species, with selective gear rules (barbless, single hooks). Any bull trout caught must be released immediately without being removed from the water.

Population Information

Population Distribution and Life History

Figure 1. Rattlesnake Creek subwatershed

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 1). 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 sub watershed (Figure 1) - This is still a draft!

Natural Barriers limiting distribution

The mainstem of Rattlesnake Creek does not have fish passage barriers.

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 (called Dolly Varden at the time) 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 1990). 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 was genetically assigned to the American River Population.

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 miles of Shell Creek and 0.5 miles 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 2). The Rattlesnake Creek spawning survey is one of the more remote surveys, typically requiring an overnight backpacking trip. Because of the remote nature and conditions made more difficult by the 2021 Schneider Springs wildfire, usually only two passes of redd surveys are attempted here. There was no spawning survey in 2021 due to the fire.

In 2024, the Forest Service completed bull trout redd surveys on Little Rattlesnake, Upper Nile, Dry, Orr and Glass Creeks. The surveys were conducted during late October, which was after the typical peak spawning period for Naches bull trout (Eckert and Kritzer 2024). No bull trout were observed, no redds (or evidence of spawning at all) was observed. This effort was to help determine bull trout use in these streams in reference to a proposed cattle grazing allotment. The Forest Service intends to survey again closer to peak spawn timing in 2025 (Gene Shull, personal comm.).

Figure 2: Rattlesnake Creek Annual Redd Count 1990-2024

Surveyors in 2024 noted that there were more Spring Chinook redds within the bull trout spawning index than observed in the past.

Other Distribution Data (eDNA, etc.)

In November 2025, The USFS collected eDNA samples in Little Rattlesnake Creek, Glass Creek, Nile Creek, and Orr Creek to determine presence/absence of bull trout prior to a grazing lease renewal. Zero samples were positive for bull trout (USFS 2026)

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).

Although there are caveats to using redd count to determine abundance, there has been a general downward trend in spawning over the period of record.

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 within the William O. Douglas Wilderness. Habitat conditions in the spawning area were excellent prior to the 2021 Schneider Springs wildfire. A Yakima River water resources inventory looking at limiting factors in the Yakima River Watershed considered 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 to be suitable (Haring 2001). However, in 2021 a lightning-induced wildfire burned over 100,000 acres in the Okanogan-Wenatchee National Forest and the headwaters of Rattlesnake Creek within the William O. Douglas Wilderness area. The burn was high severity in this area and burned to the crown, killing much of the coniferous forest. In the years following the fire, redd surveyors have noted substantial increase in fine sediments, primarily in the mainstem of Rattlesnake creek downstream of McNeil Creek (WDFW Redd Survey Database observations).

Bull trout juveniles rear above and below the wilderness boundary. Below the boundary the creek flows primarily through National Forest land and WA State DNR 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) 5-6 miles upstream of the mouth and several on the private land near the mouth. The upstream residences are not believed to be significantly affecting habitat quality in the creek. Haring (2001) described habitat conditions 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.

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 most tributaries were surveyed in 1992 and 1994, including North Fork Little Rattlesnake, Three Creeks, Dog Creek, Lookout Creek, Little Hindoo Creek, Elkhorn Creek, Nelson Creek, Little Wildcat Creek, McNeil Creek, and Shell Creek (USFS archives?). 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 between 2007 and 2023 is a monitoring gap. In September 2023, the Bull Trout Task Force installed a temperature logger in the spawning area of Rattlesnake Creek and left it over winter. In June of 2024 they installed one logger in each spawning index, including one logger in Shell Creek, one logger in Little Wildcat Creek, and one logger in Hindoo Creek. One logger was installed downstream near the USFS 1502 rd. crossing but it was either lost or stolen and the data was not able to be retrieved. The BTTF intends to continue monitoring temperature as long as funding allows.

Threats

Connectivity

Fish Passage Barriers

Threat Severity: Insignificant

No known passage barriers exist between FMO habitat and the Rattlesnake Creek spawning grounds.

Entrainment

Threat Severity: Unknown

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.

Dewatering due to flow management

Threat Severity: Unknown

While the mainstem river may not dewater completely, diversion of water during critical migration windows can result in flows that impact fish passage.

Land-use Issues

Forestry

Threat Severity: Unknown, likely insignificant

Some timber harvest occurred in the Rattlesnake Creek watershed between 2001 - 2010, primarily in the vicinity of Devils Canyon and Little Rattlesnake Creek. The impacts to bull trout are unknown. Harvest did not occur in the Wilderness.

Agriculture and Grazing

Threat Severity: Unknown, likely insignificant

There has been an active sheep grazing allotment in the lower portion of Rattlesnake Creek for decades. Impacts to the riparian area and stream habitat were minimal. Sheep are fairly well contained and are moved along by shepherds which prevents over grazing to any one area. The Okanogan-Wenatchee National forest is in the process of converting the Rattlesnake sheep allotment to cattle, which are more difficult to monitor and contain. The EIS for this grazing change included a new analysis on impacts to bull trout and the forest seems committed to reducing impacts. The cattle will be contained and kept away from the creek using a new technology: VENCE (virtual fence), where each cow has a GPS collar and with sound cues and electric pulses, should be deterred from getting too close to the riparian area. The BTWG should work with USFS to ensure no impacts from cattle.

Recreation

Threat Severity: Unknown

A significant channel-spanning recreational dam was removed from Rattlesnake Creek in 2023 from a relatively remote dispersed campsite. The dam was reported by an angler and was in a location not frequently visited by the Bull Trout Task Force. Some of the dispersed camping along Rattlesnake Creek is accessible only by 4X4 vehicle and is not frequently monitored. Signage was posted. Although this particular dam looked like it could be a fish passage barrier, the full impacts of recreation are unknown.

One of the BTTF temperature loggers near the USFS rd.1502 bridge was stolen.

Roads and Development

Threat Severity: Unknown, likely insignificant

With the exception of a few private parcels near the mouth of Rattlesnake Creek, development is minimal. Roads exist in the lower part of the watershed outside the wilderness boundary. There are a few 4X4 roads that provide access to the creek. Most of the roads are high above the canyon and on ridges, not likely impacting the stream.

Mining

Threat Severity: Insignificant

There are a few remote Gold mines on the North Fork of Rattlesnake Creek that utilize surface mining techniques. According to "The Diggings" these mines are still active but the extent of mining is unknown. It is a very remote location with no road access.

There is no other mining activity in the watershed.

Ecological Interactions

Brook Trout

Threat Severity: Unknown

Brook trout have been observed in the lower portions of Rattlesnake Creek and in the Naches River but their distribution in the upper watershed is unknown. No evidence of hybridization was found during genetic sampling, but genetic samples have not been collected in the past two decades. Warming stream temperatures and increased siltation from the wildfire may benefit brook trout.

Other Invasive Species

Threat Severity: Insignificant

Other invasive species have not been documented.

Diminished Prey Base

Threat Severity: Unknown, likely significant

Diminished prey base was determined to be a priority threat in the 2012 BTAP (Reiss et al. 2012). Anadromous fishes can access and spawn in Rattlesnake Creek, and in 2024 several adult spring-run Chinook and Chinook redds were observed in the reach where bull trout spawn. However, it is unlikely that the salmon population has recovered to a level where this threat is insignificant.

Disease

Threat Severity: Insignificant

Disease has not been documented in Rattlesnake Creek.

Water Quantity and Quality

Flow issues/dewatering

Threat Severity: Unknown

Dewatering occurs in the vicinity of the McNeil Creek confluence with Rattlesnake Creek near the upper end of the spawning reach. Flow is interrupted and isolated pools of standing water form. The timing and extent of this dewatering has not been monitored as it is a very remote location. See Dewatering due to flow management above for other concerns.

Current and modeled future temperature conditions

Threat Severity: Significant

Figure 3. Rattlesnake Creek temperature monitoring sites in reference to one another. RATC1 depicts the downstream most site that data was collected for in 2024.

Figure 4. Mainstem and tributary water temperatures in the spawning indexes during 2024, a drought year. Aside from RATC2, a logger configuration error caused data to stop being collected mid-August.

Water temperatures in the upper part of Rattlesnake Creek have likely been affected by the lack of shade after the Schneider Springs fire burned the majority of the riparian area along the river. One season of water temperature monitoring during a drought year, 2024, showed mainstem temperatures in excess of 10 C from early July through the spawning season (Figures 3 and 4). Little Wildcat creek, a tributary to Rattlesnake Creek maintained cold temperatures below 10 C throughout the summer, however, Shell Creek was comparable in temperature to the mainstem site ~3 miles downstream of there (12+ C for most of the summer). Shell Creek could be contributing to mainstem warming within the spawning area.

Other changes in hydrology

The Schneider Springs fire caused substantial erosion and sedimentation in Rattlesnake Creek. The fire was in 2021 and as of 2024 surveyors have noted sediment has been only partially flushed out. High quantities of fine sediment may be negatively affecting water quality and thus redd viability.

Fisheries Impacts

Angling Regulations/Fisheries Use/Poaching (Recreational)

Threat Severity: Unknown

Rattlesnake Creek is not a very popular fishery due to its remote nature and canyon geomorphology. There is some limited angling pressure in the few accessible locations along the lower reaches of the creek. Rattlesnake Creek bull trout in Naches FMO habitat are likely encountered by anglers more frequently than in the creek itself. Bull trout are known to overwinter in the pool where the Rattlesnake meets the Naches River (Mizell and Anderson 2010). The regulation for Rattlesnake Creek is catch and release only for all species, with only single-point barbless hooks allowed.

Management/Monitoring (Research)

Threat Severity: Insignificant

There is no fisheries research occurring in Rattlesnake Creek except for annual redd counts.

Other Threats

Low Population Resiliency

Climate Change

Wildfire Impacts

Summary of Primary Limiting Factors and Threats

With a geometric mean of <50 redds annually low abundance is identified as a moderate threat. This population is not considered a candidate for supplementation due to a stable population trend. Water temperature and climate change impacts on the hydrograph are emerging threats. The next highest threat to this population is limited prey base and although the level of this threat is unknown it is believed to be of significant severity. Currently steelhead, spring chinook, and coho spawn in Rattlesnake Creek, but at much lower numbers than historically. The potential for entrainment into irrigation diversions is present in the lower reaches. Water diversions from Rattlesnake Creek can also cause low flows in the mainstem and impacts to migrating or rearing juvenile bull trout. Dewatering, invasive species (brook trout), altered flows, development, angling, forest management issues, roads, passage barriers (potential), fine sediment due to wildfires, and recreational impacts are all present in the FMO habitat and lower rearing reaches of Rattlesnake Creek. Each of these impacts are not believed to impact the population individually, but the combination of all of these factors may be substantial. There is a sheep grazing allotment in the Rattlesnake drainage but this has never been documented to damage riparian areas. This may change as the allotment transitions to support cattle grazing. 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 anthropogenic threats are minimal. However, temperature should be monitored and riparian restoration should be considered to reduce water temperatures. In the lower reaches of Rattlesnake Creek and in the Naches River, in-stream restoration and riparian habitat enhancement actions would benefit this population. 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: Restoring Healthy Salmon Populations and Passage at Major Storage Dams (Bumping and Rimrock). Revitalizing salmon and steelhead runs in the Yakima Basin would significantly improve nutrient limitations and thus 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.

Monitoring Needs/Key Questions

---

• Dewatering extent and timing in the upper spawning index

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

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 Action #1: Address Impacts of Diversions on Bull Trout

Rattlesnake Action #2: Expanded Redd Surveys

Rattlesnake Action #3: Address Recreational Impacts

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 Naches Populations small group. Reviewed, and updated and approved by BTWG in May 2025.

Specific detail on out of cycle updates: