North Fork Tieton Bull Trout Population

Overview

The North Fork Tieton River population is one of three populations in the Rimrock Population Group. North Fork Tieton River flows into Rimrock Lake at its western end. The river originates in the Goat Rocks Wilderness Area and flows for about 10.5 miles before entering Clear Lake, a small (5500 acre-foot) impoundment formed when Clear Creek Dam was constructed in 1914. The wilderness boundary is approximately five miles upstream of Clear Lake, with the lower portion of the river located in the Okanogan-Wenatchee National Forest. Several small tributary streams enter the North Fork Tieton River above Clear Lake, the largest being Scatter Creek. Clear Creek, once the most significant tributary of the North Fork Tieton River, now flows into Clear Lake from the west. Below Clear Creek Dam, the North Fork Tieton River flows for about 0.7 mile before entering Rimrock Lake (at high pool).

Population Information

Population Distribution and Life History

Figure 14. North Fork Tieton subwatershed. update spawning survey reach.  it appears to start much further downstream than it actually does.  also, it is unclear what the dark orange highlight around the reach between scatter creek camp and half way to the barrier falls is trying to designate.  Seems like it should just be FMO and known presence.  why is there a separate "known spawning" designation in light yellow in addition to the "spawning survey" designation in red?

The North Fork Tieton River population was "recently discovered” although catch records from the 1950s documented the presence of adult bull trout (referred to at the time as Dolly Varden) in Clear Lake and biologists from CWU found a single adult bull trout above the lake in 1996 (Craig 1996). However, there was no clear indication that a spawning population inhabited the North Fork Tieton River until 2004. During the fall of that year, a fish census was conducted in the river that documented the presence of 14 bull trout including seven juveniles (<199 mm TL), five that were considered subadults (200-299 mm TL), and two large (>500 mm TL) adults (USFWS 2004). In addition spawning activity was confirmed with the discovery of a single redd and a couple of large adults observed about 0.6 mile below the waterfall. As a result of the data collected and observations made in 2004, local population of bull trout was officially recognized in the North Fork Tieton River (Thomas 2005). This population is adfluvial, based on the large size and documented migration of tagged fish past USFWS PIT antennas. A resident component may exist, but this has not been confirmed.

Although data are limited it appears that the majority of spawning activity occurs above the wilderness boundary located about five miles upstream of Clear Lake with most of that occurring in the reach extending from the waterfall downstream for approximately two miles (Figure 14). Since 2008, spawning in Hellbender Creek, a tributary which enters the river from the west in this two-mile reach, has been well documented. Hellbender creek is now an established redd survey index and is surveyed yearly. Juvenile rearing likely occurs throughout the reach above Clear Lake, first noted in Thomas 2005. but all juvenile observations to date have been above the wilderness boundary.

Reference back to helicopter transport effort into clear lake?

The primary FMO habitat for adults and subadults is Rimrock Lake (see discussion under Population Monitoring) although many fish pass downstream through the Clear Creek Dam spillway channel or outlet works. It is possible, perhaps probable, that these life stages utilize FMO habitat in Clear Lake for some limited period of time, but is considered unlikely that they remain there over the winter. Timing of migration into the North Fork Tieton River for spawning is unknown but will be addressed in a multi-year study beginning in 2012. Passage conditions at Clear Creek Dam will also be comprehensively evaluated. As of the 2012 BTAP, timing of migration into the North Fork Tieton River was largely unknown.

Natural Barriers limiting distribution

Figure 2. North Fork Tieton Falls

A waterfall exists about nine miles upstream of Clear Lake representing an impassable barrier for migratory fish (Figure 2).

Population Genetics

See information under population genetics section of Rimrock Lake Populations Page

Pull out within-population genetic information. Small effective population size. (citations?)

Hybridization: craig to see if we have pop specific records from TH

Six genetic samples were collected from bull trout juveniles during the 2004 study (USFWS 2004). Efforts to collect additional samples were constrained by turbidity issues until 2010 when enough genetic samples (30+) were collected to analyze the uniqueness of this population. Results indicate that this population is genetically distinct from all other populations in the Yakima Basin including the other adfluvial populations residing in Rimrock Lake (Indian Creek and South Fork Tieton River) to which it is physically connected (Small and Martinez 2011). Of the genetic samples analyzed to date, three have been identified as brook trout x bull trout hybrids. Connectivity and thus the potential for genetic exchange with downstream populations in the Naches River fluvial system was eliminated by the construction of Tieton Dam in 1925.

USFWS Trap and Haul CCD genetic data? Updated hybridization data.

Entrainment through Tieton dam may be contributing to one-way gene exchange with Naches fluvial populations.

Population Monitoring

The monitoring history for the North Fork Tieton River population is fairly recent. In 1993, the Forest Service captured a juvenile bull trout in a minnow trap on the margins of Clear Lake (USFS 1993b). The first organized investigation of bull trout in the North Fork Tieton River appears to have occurred in 1994 when Central Washington University coordinated with WDFW to monitor the effectiveness of the fish ladders constructed in the spillway channel of Clear Creek Dam two years previous. No bull trout were observed in the ladders but nine adult bull trout were captured and tagged below the base of the dam. It is assumed that these fish were attempting to find a migration route upstream and would thus have belonged to the North Fork Tieton River population. Two years later an adult bull trout was observed in the North Fork Tieton River about six miles above Clear Lake during a snorkel survey (Craig 1996). Presence of a spawning population existed in the North Fork Tieton River was confirmed in a 2004 fish census survey conducted cooperatively by the USFWS and the Forest Service (USFWS 2004). The details of this monitoring effort were discussed above in the Population Distribution and Life History section.

WDFW radio-tracked five adult bull trout captured and tagged in the North Fork Tieton River below Clear Creek Dam in July 2005. These fish all migrated downstream to Rimrock Lake by late fall to overwinter and returned to the area near the mouth of the North Fork by early June the next year. Only one eventually entered the river and did not attempt to ascend the ladders in the spillway channel (Mizell and Anderson 2008). However, one fish that was collected below Clear Creek Dam in 2005 did genetically assign to the North Fork Tieton River population (Small and Martinez 2011). Apparently the reach below the dam is used by all Rimrock Lake populations, not just North Fork Tieton River adults intending to migrate above the dam to spawn.

As of 2024, the stilling basin and short river section below the dam are monitored by the USFWS via PIT antenna and their trap and haul program. It remains true that bull trout from all the Rimrock Lake populations use this area and congregate below Clear Creek Dam. Since 2015, 141 bull trout identified as North Fork Tieton fish have been transported above the dam and released into Clear Lake.

Add other NFT monitoring information (USFWS efforts)? Locations of PIT Antennas.

As with the other two Rimrock Lake populations, North Fork Tieton River bull trout are subject to entrainment through the outlet works of Tieton Dam. The results of studies investigating the entrainment of Rimrock Lake bull trout through the outlet works of Tieton Dam were discussed previously in the Population Monitoring section for Indian Creek. Also discussed was the collection of 37 bull trout from the stilling basin directly below Tieton Dam during a fish salvage effort in 2005 and the subsequent analysis of genetic samples taken from those fish. This analysis revealed that two of the bull trout captured in the stilling basin below the dam assigned to the North Fork Tieton River population (Small et al. 2009). This provides further evidence that the North Fork Tieton River population uses Rimrock Lake as FMO habitat.

In 2010, snorkel surveys coordinated by the USFWS were successful in collecting enough genetic samples from juvenile bull trout to supplement those collected previously and enable an analysis of the genetic uniqueness of the North Fork Tieton River bull trout population (Small and Martinez 2011).

Redd Surveys

The spawning period for the North Fork Tieton River population occurs primarily during the month of September but can extend through mid-October. Fish begin entering the lower North Fork Tieton River in late June and re-enter Clear Lake by early November presumably after spawning (Beebe et al. 2024) Craig to send data. Problems have been encountered in attempting to annually conduct complete redd surveys in the North Fork Tieton River. The river is glacial-fed and is usually milky with glacial flour until late in the summer. Its hydrology is “flashy” and river discharge quickly changes from stable and clear to high and turbid after fall rains or high daytime temperatures, both of which are common during the bull trout spawning period. This results not only in difficult survey conditions but also in conditions in which redds become undetectable if an event occurs before or between surveys. Although the first redd was observed in the North Fork in 2004, a complete survey was not accomplished until 2007 for the reasons just described. The surveys conducted in 2009 and 2010 were incomplete.

Figure X. North Fork Tieton Annual Redd Counts 2004-2024

Surveys are conducted in an index reach approximately 2.3 miles in length, which ends at the barrier waterfall. Included in this index area since 2008 is a small, unnamed tributary (since been named Hellbender Creek)—its mouth is barely detectable from the main channel—that has contained a surprising number of bull trout redds. For logistical reasons (i.e., access and hydrologic timing), just two survey passes are attempted annually. During the first year of redd surveys 37 redds were observed and the unnamed tributary (Hellbender Creek) was not included. Redd counts have ranged from the high 30s to single digits over the past 20 years, with a record count of 39 in 2017 (Figure X). The yearly average is around 17 redds. There was no survey in 2018 due to the Miriam widlfire. The count was 28 redds in 2008 and included 5 redds found in the tributary. As mentioned above, the surveys in the two subsequent years were not complete and thus counts were lower with 15 and 18 redds observed in 2009 and 2010, respectively. Favorable survey conditions prevailed in 2011 however and just 11 redds were counted.

An exploratory redd survey in 2023 documented 5 bull trout redds below the wilderness boundary, in the vicinity of the Scatter Creek Trailhead. This information may warrant additional exploratory surveys in the future to determine if this is now a primary spawning location.

Link to survey methods / redd reports

Population Status and Trend - more discussion on what to include in this section

Due to its very recent recognition the status of this population has not been rated by either the WDFW or the USFWS. Based on redd counts to date, it appears to be depressed. <-- is this still correct or has there been an official designation since 2012? Check species status assessment (core area scale?).

Adopt approach of SSA and downscale to population?

With limited data it is difficult to determine a trend for this population. The USFWS estimates survival probability using PIT tag detections from antenna sites in the upper and lower North Fork Tieton River. Since 2013, annual survival probability has ranged from 0.60 - 0.70 (mean = 0.64; Beebe et al 2024)

(Insert graph of redd counts; ideally via live link)

Habitat

Habitat Overview

The North Fork Tieton River is one of the higher elevation streams inhabited by bull trout in the Yakima Basin. Elevations range from 3,000 feet where it enters Clear Lake to about 4,000 feet at the impassable waterfall located just over nine miles upstream. As mentioned previously, approximately four miles of the river is in the Goat Rocks Wilderness with the lower five miles flowing through the Okanogan-Wenatchee National Forest. A Forest Service road (1207) parallels the river for these five miles but is rarely close to it with thick forest separating the two. The main human activity in the watershed is recreation—

,In short, the North Fork Tieton River is undisturbed above the wilderness boundary and for the most part below it as well. The floodplain is connected and properly functioning, the riparian corridor is healthy, LWD is plentiful, and water quality is excellent (USFS 1998a). Pool frequency did not meet Forest Plan standards but it was noted that the evaluation was limited to full channel pools and that smaller pools (not evaluated) were prevalent in riffle habitat. The North Fork Tieton River is a relatively sediment-rich river. This is likely due to the fact that it received a great deal of fine volcanic material during the 1980 eruption of Mount St. Helens and because its waters are of glacial origin. Much less fine sediment is present in the upstream reaches, which may explain why all of the spawning activity and juvenile fish observed to date have occurred above the wilderness boundary.

The Miriam wildfire started on July 28, 2018 and burned through 5,400 acres of the North Fork Tieton watershed culminating around September 18th, 2018. The fire primarily burned upland of the riparian corridor with overall low soil burn severity.

In recent years (2022, 2023, 2024), dewatering has been observed in the two mile reach below the barrier falls during low flow periods. The river seems to have migrated into several new, braided, channels in the forest. Highly dynamic channel that may shift from year to year.

Climate Change Impact on Habitat - add section?

Observed vs future?

Rating of climate impact for each population relative to one another?

Extent of available spawning and rearing habitat

Check above under overview of population distribution and life history? Pull down description or remove this sub heading

Habitat Monitoring

A number of documents explore preliminary designs and options for fish passage facilities at Clear Creek Dam (WDFW 2003; WDFW 2007; USBR 2008b). Fish passage is considered potentially problematic for bull trout during the presumed spawning migration period (July-September). addressed above in population distribution section.

Field Habitat Surveys

The Forest Service completed a habitat survey using Hankin and Reeves protocol on the North Fork Tieton River (Hankin and Reeves 1988; USFS 1998a). In this survey, data were collected on pool/riffle frequency, riparian and channel condition, substrate, LWD, and temperature.

Stream Temperature Data

The North Fork Tieton River was monitored for temperature via thermographs deployed at the FS 1200 road crossing during the summer low flow period in 7 out of 11 years from 1997-2007 (USFS 2011a). A thermograph was also deployed at the confluence of Scatter Creek in 1997. Temperature data since 2007 is a monitoring gap. USFWS started monitoring temperature again in 2018 in two locations upstream of Clear Lake and downstream of Clear Creek Dam in the spillway channel fish ladder, and the outlet channel of Clear Creek Dam. In 2024, Bull Trout Task Force contributed additional temperature loggers in Hellbender Creek, and the upper 2.3 miles of spawning habitat (one logger below the falls, one logger in the index downstream of Hellbender Creek confluence)

Other Habitat Data/Monitoring

Anything to put here? Keep this sub-heading?

Threats

Table 11. North Fork Tieton threats, highest severity rating in any life stage/effect category, abbreviated list of associated actions and action priority.

Connectivity

Fish Passage Barriers (Check/update FDSI)

A multi-year study from 2012 to 2015 aimed to address questions about migration including the efficacy of the existing fish ladder. Clear Creek dam This dam was originally constructed without fish ladders. In 1992, the USBR constructed two ladders in the steep bedrock spillway channel adjacent to the dam; the upper ladder is a pool and weir that appears to be functional but the lower one (a denil ladder) was poorly engineered and has persistent problems with bedload accumulation. Without the benefit of an effective ladder, passage conditions up the channel for bull trout are rigorous at best and most likely impossible at higher flows. The data acquired during this study will be critical to determine the extent to which passage conditions at Clear Creek Dam are impeding successful migration and what can be done to alleviate the problem.

During the Clear Creek Dam Fish Passage Assessment from 2012-2015, it was discovered that the fish ladder constructed in the spillway channel adjacent to the dam was not being used by bull trout for two main reasons. First, bull trout were drawn to the base of the dam by cooler hypolimnetic water releases from Clear Lake as opposed to the warmer surface water flowing down the spillway channel. Second, the fish ladder was not built using fish passage criteria and was ultimately considered too steep and turbulent for fish to ascend it even if water temperatures are suitable (Thomas and Monk 2016). In 2016, the work shifted to trap and haul where bull trout are collected at the base of the dam, PIT tagged, and then tested to determine their population of origin and whether they have hybridized with brook trout. Based on the results of the genetic tests, bull trout are either transported upstream and released into Clear Lake (North Fork Tieton River origin), released downstream of the stilling basin (Indian Creek or South Fork Tieton River origin), or euthanized (brook trout/bull trout hybrid). Since 2015, 141 bull trout identified as North Fork Tieton fish have been transported above the dam and released into Clear Lake. An additional 112 bull trout identified as South Fork Tieton River or Indian Creek fish that also migrated to the base of the dam, were captured and released downstream of the stilling basin while 15 fish identified as brook trout/bull trout hybrids have been euthanized. Trap and haul and PIT tag monitoring is ongoing.

With the data to reflect significant entrainment and lack of adequate passage at Clear Creek Dam, USBR has funding and construction is scheduled for 2025 for a functional fish ladder, which will reconnect Clear Lake and Rimrock Lake to migrating bull trout.

Entrainment (Dams? Irrigation Diversions?)

Copy from SF Tieton

Dewatering due to flow management

Address coonditions in NF Tieotn acorss reservoir bed

Land-use Issues

Forestry

Timber harvest occurred in the past but well upslope of the river. The area is now designated as Late Successional Reserve and will receive very little future harvest. Road density in the drainage is low. REference tieton forest project proposal?

Agriculture and Grazing

livestock grazing does not occur

Recreation

primarily hiking and horseback riding on trails that are not directly on the river. There are no established campgrounds; dispersed campsites are limited and generally not in close proximity to the riverbanks. There are several dispersed campsites with hard-to-notice access roads off the main road 1207. Recreational rock dams have been found by the Bull Trout Task Force at some of these locations.

Address Clear Lake Recreation infrastruicture and use

Recreational mining? Rock hounding for thunder eggs

Roads and Development

A Forest Service road (1207) parallels the river for these five miles but is rarely close to it with thick forest separating the two. Note camps etc aroudn lake

Mining

Not a current threat.

Ecological Interactions

Brook Trout

Known to be abundant. 2004 Snorkel 7 miles up from clear lake. 621 brook trout (gary citiation). Clear creek. Suspected hybrids observed.

Other Invasive Species

Copy from Indian Creek

Diminished Prey Base

Copy from Indian; note ongoing heavy stocking of Clear Lake

Impact of draw downs on prey base. Hanson reference? Zooplankton reports?

Water Quantity and Quality

Flow issues/dewatering

Dewatering in the 2 miles downstream of the barrier falls. Potential passage issues and stranding pools

Current and modeled future temperature conditions

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

Fisheries Impacts

Angling Regulations/Fisheries Use/Poaching (Recreational Fishing)

In 2011, the Bull Trout Task Force conducted creel surveys in Clear Lake during the summer months. Fifty five anglers were interviewed and no bull trout were reported caught by any of these anglers (WDFW 2011). Previous creel surveys and observations by WDFW biologists during annual fishing derbies support this evidence that bull trout are not commonly caught in Clear Lake, despite heavy fishing pressure throughout the summer season (E. Anderson, WDFW, pers comm).

The BTTF regularly visits clear lake for outreach in the summer months and it is well documented that anglers fishing the river section below Clear Creek dam consistently catch bull trout. It is unclear how many bull trout are poached vs. released. In 2023 the Bull Trout Task Force talked with an angler who admitted to catching a bull trout in Clear Lake and released it based on informational signage that helps anglers identify bull trout. BTTF notes that a small percentage of the anglers communicated with at Clear Lake know about bull trout and can confidently identify them. As of 2023, BTTF has started leaving identification cards for Spanish and English speakers at Clear Lake boat launch and day use areas. Language barriers have been identified as a common issue with outreach efforts in this area.

Regulation context

Fisheries Management/Monitoring (Research)

note survival estimates of tagged fish??

Review of when/where/why fish are handled

Summary of Primary Limiting Factors

(Look at threat summary table format and Teanaway example)

Tied to stuff from SSA

The highest severity threats to the North Fork Tieton River population are associated with passage issues both at Tieton Dam, which is a complete passage barrier, and at Clear Creek Dam, which appears to be problematic for passage under certain conditions. Also resulting from lack of passage at Tieton Dam are the threats of entrainment and lack of prey base. <-- prey base in Rimrock was previously mentioned as good? Rephrase to lack of marine derived nutrients/no anadromous passage. Other threats to this population include illegal angling in Rimrock Lake and possibly Clear Lake, and introgression with brook trout. Low abundance and unstable redd numbers are possibly likely the result of passage problems at Clear Creek Dam.

Introgression of brook trout seems to be an emerging threat. brook trout have been observed all the way to the upstream passage barrier, and have been documented spawning. It is well known that Clear Creek, a tributary that flows directly into Clear Lake is a brook trout hotspot.

While forest management and recreation issues—both dispersed and managed forest roads and campsites—are present in the North Fork Tieton River population area, they are not believed to be significant threats. Agriculture, altered flows, development, dewatering, grazing, limited extent of habitat, transportation issues, and mining are not present in this population area.

Dewatering has been documented in the 2.3 mile spawning survey index below the barrier falls each year from 2022 through 2024. In low precipitation years, this dewatering may affect spawning and rearing and cause adults to become stranded.

Recovery Strategy

Population-level Recovery Strategy

(High-level discussion of priority needs)

** Old Narrative from 2012

This population has been identified as a high priority “Action” population. The highest priority actions are the broad-scale action of Passage at Tieton Dam and the immediate population-scale action of improving passage at Clear Creek Dam. Adults from this population appear to use Rimrock Lake for FMO habitat and are targeted by anglers. Continued outreach to educate anglers is a priority. Brook trout introgression has been documented in this population and should continue to be monitored, although no brook trout removal efforts are recommended at this time. Implementing carcass analog placement to address lack of marine derived nutrients will likely only happen after a successful pilot study is implemented elsewhere in the basin and deemed necessary. Rimrock Lake contains a healthy population of reproducing kokanee salmon while Clear Lake is heavily planted with rainbow trout. Both provide an abundant food source for North Fork Tieton River bull trout. <--- contradiction with prey base listed as threat above

Passage is critical to the long-term genetic health of the population. Fish passage planning at Clear Creek Dam is complete and construction of a new fish ladder and cool water intake pipe will occur from 2025 - 2027. Planning for two-way fish passage at Tieton Dam is underway with completion of designs expected by 2027

Climate specific strategy?

Monitoring Needs/Key Questions

---

Exploratory surveys upstream of barrier falls

eDNA

Habitat assessment in Clear Creek

Actions

Completed Bull Trout Recovery Actions

(Mix of narrative and table, or could be a database)

• Fish ladders were installed in the spillway channel in 1992. Only one of these, the pool and weir at the upper end, is functional at all flows. The denil ladder at the lower end is poorly designed and does not function to pass bull trout.

• Fishing regulations were implemented to protect bull trout in North Fork Tieton River (see Appendix F).

Recommended Actions

(Link to or summarize BTAP database) Actions detail?

Relevant Multiple Population Actions

• Multiple Populations #1: Outreach on bull trout conservation issues (landowners, recreationists, anglers, school groups, and others).
• Multiple Populations #2: Continue annual spawning surveys to monitor trends in population abundance. (add PIT array and efishing effort USFWS 2024)
• Multiple Populations #3: Continue temperature monitoring
• Multiple Populations #5: Carcass analog placement if pilot studies demonstrate success
• Multiple Populations #7: Current genetic samples indicate that this population may have a high level of introgression with brook trout. Continue to monitor, targeting fish that show phenotypic hybrid characteristics.
• Multiple Populations #8: Manage Tieton Dam operations to reduce entrainment.
• Multiple Populations #9: Periodic entrainment studies at storage dams.

North Fork Tieton River Actions

• North Fork Tieton Action #1: Provide Bull Trout passage at Clear Creek Dam.
• North Fork Tieton Action #2: Environmental DNA sampling in tributaries
• North Fork Tieton Action #3: Evaluate options to address Brook Trout

Update Notes

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

Additional edits proposed by Alex Conley, aimee Taylor and Rimrock populations small group. Reviewed, and updated and approved by BTWG in Nov 2024.

Specific detail on out of cycle updates