1. Clear Creek Dam Fish Passage Assessment
USFWS: Jeff Thomas, Pat Monk, Rob Randall
WDFW: Eric Anderson, John Easterbrooks
USBR: Arden Thomas, YRBWEP

2. Clear Creek Dam was originally built in 1914, impounding Clear Lake with an active capacity of 4,400 acre-feet. The dam is located one kilometer above Rimrock Reservoir on the NF Tieton River. Bull trout spawn in the NF Tieton upstream of Clear Lake. Prior to this assessment it was assumed they lived in Rimrock.

7. Study Objectives
Determine if and when bull trout attempt to migrate past Clear Creek Dam
Assess passage success under various flow conditions
Determine post-spawn migration timing and the role which Clear Lake plays in the population’s life history
Ancillary objectives include determining spawning frequency, collecting genetic samples, and estimating the size of the NF Tieton bull trout population

8. Study Methods
Trap post-spawn bull trout in the NF Tieton River using a picket-weir box trap deployed in the Goat Rocks Wilderness 6.75 miles upstream of Clear Lake
Capture adult bull trout directly below Clear Creek Dam by hook and line
Surgically implant 23mm Half-Duplex PIT tags
Obtain genetic samples and collect other data
Construct PIT tag detection arrays at key locations to track migrational movement

11. 2015 mean daily water temperatures (°C )

12. Trap Data
Trap was operated for three weeks in mid to late September ( )
A total of 29 fish were tagged (14 males, 15 females)
During the last season, five fish were tagged. Seven other fish trapped were recaptures from the two previous years
All 29 fish tagged genetically keyed to the NF Tieton River population, however…
Six (21%) were first generation hybrids (bull trout x brook trout) .

13. Hook and Line Data
Hook and line sampling was conducted in the stilling basin directly below Clear Creek Dam on July 31 (2014) and July 2 (2015)
A total of 28 fish were captured, 22 were tagged (7 males, 15 females)
Genetic samples were obtained from 25 fish. Twenty-three (92%) keyed to the NF Tieton population. Only one was a hybrid
One of the bull trout captured in 2015 genetically keyed to the SF Tieton River population and another to Indian Creek .

14. Key Findings
27 of the 29 fish tagged at the trap were detected in subsequent years of the study
20 of these fish migrated back to Clear Lake after spawning where they overwintered
Just four fish were confirmed to have migrated downstream of Clear Lake after spawning
The maximum likelihood estimate for the size of the spawning population was 59 individuals with a 95% confidence interval of

15. Key Findings (cont’d)
Large numbers of NF Tieton bull trout congregate directly below Clear Creek Dam in July and August
The size of this population was estimated at 71 individuals with a 95% confidence interval of 41-95
These fish, without exception, appear to be unable or unwilling to ascend the spillway channel
Seven bull trout were unsuccessful in 24 attempts over the course of 20 different days

16. The Bottom Line
The North Fork Tieton Bull Trout population exists in two segments which are roughly equivalent in size. One segment spawns in the river above Clear Lake and predominantly uses the lake for foraging and overwintering habitat. The other segment resides in Rimrock Lake and congregates below Clear Creek Dam in the summer, unable to migrate up the spillway channel. Both high water temperatures and extreme hydraulic conditions preclude upstream passage. .

17. Next Steps: Adult Bull Trout Transport
Goal: The goal of transporting adult Bull Trout above the dam is to maintain the genetic diversity and population fitness of the NF Tieton Bull Trout population.
Objective 1: Capture and transport adult Bull Trout until fish passage is implemented
Tagged Bull Trout will be moved immediately, untagged fish will be tagged, photographed, genetics, moved if they are positively ID
Hybrids will be culled, uncertain fish tagged and released to stilling basin until genetics are completed

18. Figure 2a. Plot of ancestry values from STRCTURE for samples analyzed in
2015 (top of plot) in comparison to the Yakima bull trout genetic baseline in the
Tieton basin. Brook trout were included in analysis to assess possible hybridization.
Each baseline sample has a color associated with their gene pool. Single ancestry individuals
have a single color from a single gene pool and mixed ancestry individuals have two
or more colors from multiple gene pools (Small et al. 2016).

20. Next Steps Continued
Objective 2: Monitor adult movements post transport
We expect most transported fish to stay in Clear Lake for some time and then go up the NF Tietion to spawn
Some fish may go back downstream if not ready to spawn or are from another population
Maintain PIT tag interrogation sites in key locations

21. Year Redds Redds/km 2007* 37 9.25 2008* 28 7 2009 15 2010 18 2011* 11
North Fork Tieton Redd Surveys
*complete survey
Year
Redds
Redds/km
2007* 37
9.25
2008* 28 7
2009 15
2010 18
2011* 11
2.75
2012* 17
4.25
2013 10
2014 19
2015* 27
6.75

22. Next Steps Continued
Objective 3: Use genetic parentage analysis to monitor reproductive success starting in 2017
Redd counts and PIT tag detections are indirect evidence of spawning success, redds can be difficult to observe
Collect genetic samples from juveniles to determine if transported adults are reproducing successfully
Depending on the number of adults transported we think around 100 juvenile genetic samples annually
Juveniles could be PIT tagged (12mm HDX) to gain insights into timing of juvenile migration downstream, age at migration, and may allow for a determination of the proportion of the juvenile NF Tieton Bull Trout population using each area
Long term monitoring could assess reduction in brook trout introgression?

23. Support Reclamation information needs for fish passage—challenging environment
Bathymetery ? reservoir temperature profile? technical meetings
December 9, 2015 >2,500 cfs,
elevation >3015

24. Thanks to everyone who helped work the trap, WDFW’s Region 3 Screen Shop, and a special thanks to Mo Small and Sarah Bell with the WDFW Molecular Genetics Lab for their excellent work