1. Examining the Effects of Juvenile Migration Timing on Adult Age of Columbia River Salmon Benjamin P. Sandford Fish Ecology Division Fish Ecology Division Northwest Fisheries Science Center NOAA Fisheries Service

2. Introduction The Columbia/Snake River System has been extensively altered with hydropower and water-storage dams. This has significantly altered salmon migration timing patterns for many reasons. Understanding the effects of these changes is important for making future management actions.

4. Objectives Characterize the relationship between Year- Of-Return (YOR) probability and various juvenile migration factors for wild yearling Chinook salmon –Barge transport or In-river migration separately –Within-year Bonneville passage date –Migration year –PDO, temperature, and other ocean conditions –Fish length

5. Methods

9. Dataset Wild yearling spring/summer Chinook salmon PIT- tagged at or above Lower Granite Dam: 1998-2007 Only used years with a “reasonable number” of adult returns to Lower Granite Dam. This necessitated analyzing barge transport separately from in-river migration

10. YOR Model – Ordinal Logistic Regression

11. Analysis Ordinal Logistic Regression Fit all pertinent models (year, day, daysq, ints) Compare using Akaike’s QAICc Plot best model fits

12. Results

13. In-riverTransported YearSmoltsAdult Returns LGRLGSLMNAdult Returns 1998204426652189239952 1999661921495936001647267 20008109267375161771388297 20011856717009511343169 20024779846942119666639287 20036616201293216846359489 2004176192026934671180122 20051536425403378466274 20063020362391947701722232 200739554719241690438202 Wild Snake River PIT-tagged Yearling Chinook Salmon

14. In-river Migration MigrationReturn Year Percent Year of Return YearY1Y2Y3TotalY1Y2Y3SAR 1998219526 873191.27 1999216547214177223.23 20008112147267 342553.29 20011427 - - -0.38 2002470984 585111.76 2003013720 065350.30 20040639067330.51 20050134025750.26 2006029736 081191.19 2007634747 1372151.19

16. Wild Yearling Chinook – In-river

19. Wild Snake River PIT-tagged Yearling Chinook Salmon Barge Transport MigrationReturn Year Percent Year of Return YearY1Y2Y3TotalY1Y2Y3SAR 199863610521269190.67 19991321044267579162.26 200011131155297444521.66 200122121261691372150.95 20022620060287970211.12 20033592789366300.27 200457542122461340.49 20053462574462340.25 20061717045232773190.76 200721157242021078120.99

21. Wild Yearling Chinook – Transported

24. Yearling Chinook – In-river

25. From Peterson et al on NOAA Fisheries NWFSC site: http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a- ecinhome.cfm

26. Summary The age of adult return (by year) of wild yearling Chinook salmon increased for later migrants, both in- river and transported. There was substantial annual variability in age distribution and relationship to migration timing. There was little evidence that fish length (at tagging at dams) explained these results, but this needs more investigation along with ocean conditions. It takes a very large number of PIT-tagged individuals to make these assessments!

27. Thanks! Mark Scheuerell and Rich Zabel COE and BPA Many PIT-tag coordinators and taggers, especially Doug Marsh and CSS staff

28. Questions

30. Wild Yearling Chinook – In-river

31. Wild Yearling Chinook – Transported