1. Is there evidence for stock segregation in Chinook salmon during ocean residence? Indicators of survival: reconstruction of juvenile size-at-emigration Is bigger better? Who survives? Jessica Miller, Oregon State University, Coastal Oregon Marine Experiment Station, Department of Fisheries & Wildlife

2. Biogeochemical tags - otoliths

3. Is there evidence for stock segregation during ocean residence? Classification success (% correct) StockYear of captureYear prior to captureRandom Central Valley (21)677148 Rogue River (10)736418 Mid-Columbia (11)706030 Average696736

4. Frequency Estimated fork length at initial emigration (mm) 12 14 20 12 3.5 3.7 Frequency Fork length at release (mm) CROOS adults from Central Valley Central Valley hatchery releases Millions of fish (50 fish) (49 fish) Reconstruct juvenile size-at-emigration Is bigger better? Who survives?

5. There is evidence for stock segregation during ocean residence Central Valley, Rogue, and Mid-Columbia stocks Variability in juvenile size-at-emigration Relative importance of smaller migrants, natural-production Contribution of ‘fry’ migrants