1. Timing of entry, distribution, and condition of chum salmon juveniles in western Alaska Nicola Hillgruber Christian E. Zimmerman Sean E. Burril

2. Outline ► Introduction & Background ► Methods ► Results  Fish catches and timing of outmigration  Distribution  Size and condition  Otolith microchemistry ► Conclusions

4. Methods

5. Kuskokwim Bay, western Alaska Quinhagak Eek Bethel Ishkowik River Kwethluk River

6. Sampling Stations

7. Methods

8. Sampling Trips 20032004 June 23-25 Week 1: May 16-22 July 24-26 Week 2: May 23-29 August 26-30 Week 3: May 30-June 5 Week 4: June 6-12

9. Results Fish abundance and timing of outmigration

10. Catch summary in 2003 and 2004 Species20032004TotalFork length [mm] Oncorhynchus keta681,2451,31331-66 Oncorhynchus kisutch120020170-170 Oncorhynchus tshawytscha5505578-125 Oncorhynchus nerka038 63-124 Oncorhynchus gorbuscha4768032-53 Ammodytes hexapterus0739 Clupea pallasii2,03512,036 Osmeridae1,81022,778+24,588 Gasterosteidae1,1171,4322,549 Others10104114

11. Mean CPUE (±SE) of juvenile chum salmon at the head of Kuskokwim Bay (station 1-3)

12. Mean CPUE for juvenile salmonids at the head of Kuskokwim Bay (station 1-3) 20042003 CohoPink ChinookSockeye

13. Results Environmental factors and juvenile chum salmon distribution

14. SST and SSS in 2004 6/06- 6/12 5/16- 5/22 Temperature Salinity

15. Surface density [m -3 ] of small copepod in 2004 5/16- 5/22 5/23- 5/29 5/30- 6/05 6/06- 6/12

16. Chum salmon CPUE in 2004 No Chum 0 - 0.01 0.01 - 0.1 0.1 - 1.0 10.0 – 30.0 1.0 – 10.0 5/16- 5/22 5/23- 5/29 5/30- 6/05 6/06- 6/12

17. Chum salmon CPUE by SSS

18. Results Size and condition

19. Weight and length of chum salmon juveniles Fork Length [mm] Weight [g] 2004 2003 186248162356 FL = 173.1 mm (Aug/Sept) Farley et al. 0

20. Energy content by size and month in 2004 2359 Aug/Sept (Farley pers. comm.) 815 river km 583221581113690

21. Results Otolith microchemistry

22. Determination of saltwater entry for Kuskokwim Bay chum and Chinook salmon Collected at SSS=12

23. Conclusions ► Chum emigration peaked in early/middle June ► Juveniles followed the river plume before moving into the bay ► Length and weight increased with season ► Condition decreased with size, season, SST ► No distinct saltwater entry signal for chum salmon juveniles

24. Acknowledgements ► Mikhail Blikshteyn ► Johnny Zutz ► Jim Peacock ► Bill Wiebe ► Wendy Whelan ► Switgard Duesterloh