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Estimating Steelhead Abundance in a High Sediment Stream: Bridge Creek, Oregon

Estimating Steelhead Abundance in a High Sediment Stream: Bridge Creek, Oregon. Ian Tattam Nick Bouwes Chris Jordan Michael Pollock. Outline. 1) Why trap steelhead in Bridge Creek? 2) 2009 Methods 3) 2009 Escapement Estimate 4) Spawner Distribution. Why Bridge Creek?

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Estimating Steelhead Abundance in a High Sediment Stream: Bridge Creek, Oregon

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  1. Estimating Steelhead Abundance in a High Sediment Stream: Bridge Creek, Oregon Ian Tattam Nick Bouwes Chris Jordan Michael Pollock

  2. Outline 1) Why trap steelhead in Bridge Creek? 2) 2009 Methods 3) 2009 Escapement Estimate 4) Spawner Distribution

  3. Why Bridge Creek? • Large Lower Mainstem John Day tributary • Suspected presence of hatchery adults • Tributary-scale restoration efforts

  4. Where’s the redd?

  5. 1) 2009 Methods • Upstream/Downstream Adult Trap • Mark-recapture estimate • Proportion of hatchery strays? • Operated 4/5/2009 to 5/28/2009 • PIT tag (cheek) • Caudal punch

  6. Trap

  7. Fish Fish Current

  8. There really are steelhead in that muddy water!

  9. 3) 2009 Escapement Estimate • Captures: • Upstream: 126 • Downstream: 84 • Downstream Recaptures: 23 • Population Estimate: 449 (344 to 625) • Capture efficiency • Upstream: 28% • Downstream: 19%

  10. 3) 2009 Escapement Estimate • CV: 15.3% for combined wild and hatchery estimate • Population size underestimated - late trap install • 19% hatchery - likely an underestimate

  11. “A” “B” Adult Length by Origin

  12. 4) Spawner Distribution

  13. RKM 12 RKM 26 PIT Detection Sites

  14. Wild: 57% Hatchery: 19% Wild: 17% Hatchery: 0% Detection of Upstream Migrating Adult Steelhead

  15. Conclusions • Steelhead are entering and spawning in Bridge Creek over a 3+ month period • Downstream trap box and seining combined resulted in sufficient recaptures • Flexible pickets allowed operation in high stream flows / velocities

  16. Conclusions • Hatchery adults appear to spawn lower in the creek than wild adults • Low reproductive success for steelhead spawning in RKM 1-9 • Are hatchery adults self-regulating?

  17. Acknowledgements Permitting: Jeff Neal and Chris James Construction: Steve Corwin, Mike Jensen, Kelly Stokes, Lonnie Goin, Kirt Cook, Glen Moodenbaugh Installation: Chris James and Nick Weber Handling/Tagging: Dan Rawding Trap Operation: Bryn Fleming

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