1. Chris Bare, Jim Latshaw, Ian Tattam, Jim Ruzycki, and Rich Carmichael Estimating Chinook escapement to the John Day River basin using a mark-recapture approach

2. Presentation Outline Monitoring adult spring Chinook –Redd counts at index sites –Redd counts at census sites –Mark-recapture using PIT tag detections 2

3. 3 John Day River Basin OREGON

4. 4 Index Census Total survey = 268 km 29% Index, 71% Census Total survey = 268 km 29% Index, 71% Census Redd Surveys

5. 5

6. 6 Concerns with Redd Counts –Index bias –Census assumptions –Detection probability

7. John Day Dam vs. Census Redd Counts 7

8. 8 PIT-tagging Chinook in the John Day Basin

9. 9 PIT-tagged John Day Juvenile Chinook

10. 10 Columbia River Pacific Ocean BON TDA MJ1 Detection Site Survey Reach

11. Estimating Abundance via Mark-Recapture 11

12. 12 -Closed population: 100% homing from detection arrays to spawning grounds -Equal pre-spawn mortality among marked and unmarked fish -Marks are retained during upstream migration -Equal number of marked males and females -Mark does not affect probability of detection -Observers correctly record all marks Mark-Recapture Assumptions

13. 13 Basinwide Marks, Captures, and Recaptures 6 65 24 9 16 12

14. 14 Basinwide Abundance Estimates

15. 15 Middle Fork Marks, Captures, and Recaptures

16. 16 Middle Fork Abundance Estimates

17. PIT-falls… 17

18. 18 Basinwide Redd Expansion vs. Mark-Recapture Estimates

19. 19 Basinwide Redd Counts vs. Mark-Recapture Estimates

20. Future Directions Genetic Stock Identification Better understanding of survival during adult life history 20

21. 21 Acknowledgements Oregon Watershed Enhancement Board Bonneville Power Administration Confederated Tribes of the Warm Springs Reservation Private landowners Field crew and volunteers

22. Chris Bare, Jim Latshaw, Ian Tattam, Jim Ruzycki, and Rich Carmichael Estimating Chinook escapement to the John Day River basin using a mark-recapture approach