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Erik Suring ODFW

Comparison of Winter Steelhead Trap Estimates in Small Basins to Other Escapement Methods and the Representativeness of ODFW Life-Cycle Monitoring Sites. Erik Suring ODFW. Oregon Coast Steelhead. ODFW Salmonid Life-Cycle Monitoring Project

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Erik Suring ODFW

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  1. Comparison of Winter Steelhead Trap Estimates in Small Basins to Other Escapement Methods and the Representativeness of ODFW Life-Cycle Monitoring Sites Erik Suring ODFW

  2. Oregon Coast Steelhead • ODFW Salmonid Life-Cycle Monitoring Project • Small basin steelhead returns do not correlate to each other or large scale returns as with coho • Determining age structure at multiple life stages allow for survival estimates and local freshwater conditions

  3. Life-Cycle Monitoring Project • Ten years of adult and smolt data • ODFW Habitat Surveys • Compare distribution of habitat conditions

  4. Life-Cycle Monitoring Project • Seven sites in the OC DPS • Non-random selection • Representative of DPS based on habitat metrics • Coho returns highly correlated with ESU returns

  5. Life-Cycle Data

  6. LCM Sites

  7. LCM Basin Size

  8. Habitat Representativeness

  9. Habitat Representativeness

  10. Habitat Representativeness

  11. LCM Representativeness

  12. LCM Representativeness

  13. Coho Trap to Trap

  14. Steelhead Trap to Trap

  15. Trap to Trap Correlations

  16. Nested Basins Coho: R2 = 0.92, p < 0.001

  17. LCM versus the DPS • Relationships between LCM and large scale abundance are not as strong for steelhead as for coho • Steelhead numbers have not varied as much as coho over the course of monitoring • Weak trap to trap correlations indicate local freshwater conditions play a larger role in steelhead recruitment

  18. Steelhead Survival Estimates • Monitoring multiple life stages • Use scales to track brood year for smolts and adults • Estimate marine and freshwater survival rates • Currently in our first or second year of adult scale collection • Also measure size and timing of smolts and adults

  19. Freshwater Survival • Single year of smolt scale data applied to all years: • Ward and Slaney (1993) Average 0.84%

  20. Marine Survival • Smolt and Adult scales at WF Smith • Ward and Slaney (1988) Range 7-26%

  21. Freshwater Age Structure

  22. Survival Estimates • Identify factors that affect smolt and adult abundance • Look at local variation in survival • Reveal trap to trap relationships • Other data we should collect?

  23. Conclusion • Adult returns to LCM basins do not correlate to larger areas or each other • Local freshwater conditions obscure a common ocean signal • Describing smolt and adult age structure will allow for survival estimates and reveal differences between LCM sites

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