Wenatchee Spring Chinook Relative Reproductive Success Study. Andrew Murdoch (WDFW) Michael Ford (NOAA) Michael Hughes (WDFW)

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1 Wenatchee Spring Chinook Relative Reproductive Success Study Andrew Murdoch (WDFW) Michael Ford (NOAA) Michael Hughes (WDFW)

2 Acknowledgements Bonneville Power Administration Chelan PUD Grant PUD

3 Study Design Adults sampled at Tumwater Dam (thru 2018) Multiple life stages - Smolt - Adult Smolts sampled at smolt traps (thru 2020) Multi-generational study (brood years )

4 Study Objective Measure the relative reproductive success of hatchery and natural-origin Chinook salmon in both natural and hatchery settings Determine the degree to which any differences in reproductive success between hatchery and natural Chinook salmon can be explained by measurable biological characteristics Estimate the relative fitness of hatchery-lineage Chinook salmon after they have experienced an entire generation in the natural environment

5 F Wenatchee Spring Chinook Salmon Relative Reproductive Success M F M RRS F Age: 3 M Age: 4 Age: 5

6 RRS (H/W) Mean RRS by Stream Female Male Chiwawa Little Wenatchee Nason Upper Wenatchee White

7 Effect of spawning location on fitness

8 RKM Spawning location H W ORIGIN Chiwawa Nason

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10 Female spawning distributions Female Distribution Relative To Channel Type Hatchery-origin Plane-bed dominant Pool-riffle dominant Natural-origin RKM

11 Differences By Channel Type Among Hatchery-Origin Redds Side View 24-26% difference in bowl depth 10-30% difference in tail apex height Flow Direction Top View 25-30% difference in redd area 24-42% difference in channel location Flow Plane-bed Pool-riffle Hughes and Murdoch in press

12 Conclusions Ford et al. (2015) Mother s spawning location (RKM)

13 Ecological Investigations Phenotypic Differences Migration timing by age Age at maturity Hatchery fish younger Sex ratio Hatchery produces more males Size at age Hatchery females smaller; males mixed Egg size Fecundity Body lipids Hatchery fish lower body lipids Behavioral Differences Spawn timing Spawning distribution Hatchery fish lower in Chiwawa/Nason Redd location Hatchery fish closer to the bank Redd morphology Hatchery fish shallower Egg retention Redd residence time Competitive ability

14 Ecological Investigations Phenotypic Differences Migration timing by age Age at maturity Hatchery fish younger Sex ratio Hatchery produces more males Size at age Hatchery females smaller; males mixed Egg size Fecundity Body lipids Hatchery fish lower body lipids Behavioral Differences Spawn timing Spawning distribution Redd location Redd morphology Egg retention Redd residence time Competitive ability Spawning habitat quality metric

15 Conclusions Hatchery fish had lower relative fitness than wild fish A greater proportion of hatchery fish spawn in the lower reaches of the Chiwawa River and Nason Creek Distribution of hatchery fish from new Nason Creek Program should be more similar to wild fish Domestication selection explains part of the difference Broodstock origin not important as in steelhead Spawning location also explains part of difference Channel type effects More important for females than males Similar trends in RRS among smolt and adult life stages Second generation results are still pending

16 1.00 Rock Island Dam Conversion Rates ( ) 0.98 Hatchery Wild 0.96 PIT Tag Conversion Rates Upstream Tumwater Location

17 Factors influencing delay time at Tumwater Dam Effect Parameter SE t P Intercept < Julian date < Mean discharge < Mean water temperature < Number of spring Chinook <0.0001

18 Factors influencing probability of reaching the spawning area Effect Parameter SE Wald P Intercept Delay time Julian date Mean discharge Mean water temperature Number of spring Chinook Year Origin Year x Origin