Synthesis Workshop Summary

1. Synthesis Workshop Summary The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline December 4-5, 2003 Newport Beach, CA 11 Proposals funded by NOAA OAR/NOS CIFAR Object: Synthesis Review Paper of the Research Results Relate temporal variability in the physical system to the ecosystem changes

2. Workshop Participants Funded Investigators: M. Alexander, A. Capotondi (CDC) S. Bograd (PFEL) K. Coyle (UAF) B. Finney (UAF) G. Hunt, J. Jahncke (UCI) N. Kachel (PMEL) N. Mantua, C. Marzban (UW) H. Maschner (Idaho State) W. Maslowski (NPS) A. Miller, D. Neilson, E. Di Lorenzo, H.-J. Kim (Scripps) S. Okkonen (UAF) T. Royer, C. Grosch (ODU) A. Trites, E. Gregr (UBC) J. Wang (ARL) Program Manager: J. Calder (NOAA) Invited Contributors: L. Fritz (NMFS) J. Overland (PMEL)

3. Synthesis Paper Highlights Title: The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Forum: Fisheries Oceanography Authors: Trites, Maschner and all contributors Thesis: Spatial and temporal variations in the ocean climate system are creating adaptive opportunities for high trophic levels which is the underlying mechanism for the decline of the Steller sea lion populations in the western Gulf of Alaska. Important results: Temporal issue - 1970s to 1990s changes Spatial issue - East vs west asymmetry in Gulf of Alaska Biogeographic transition point at 170W Basin-scale climate changes have regionally sensitive impacts Upscaling from local complexities to broadscale regularities Eddy variance changes in western Gulf

4. Outline The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Physical Ocean-Atmosphere Data Analysis Ocean Model Results: Coarse and Eddy-Permitting Bio-Geography: Samalga Pass Transition Point Paleo-Perspective: Isotopes and Archeology

5. Outline The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Physical Ocean-Atmosphere Data Analysis Ocean Model Results: Coarse and Eddy-Permitting Bio-Geography: Samalga Pass Transition Point Paleo-Perspective: Isotopes and Archeology

6. Sea Surface Temperature Trends in the Gulf of Alaska • Analysis of COADS SST, 1950-97 • SST clusters into 5 dynamic regions • regional differences in long-term SST behavior in eastern Subarctic Pacific Bograd et al., 2004

7. NL PC1: 32% of variance Nonlinear PCA results from Marzan, Mantua, and Hare:based on 22 abiotic indices from the Pacific for 1965-2001 NL PC2: 23% of variance

8. North Pacific Regime Shifts: State Changes in Forcing SSTA SLPA, WindA “cool” “warm” “cool?” Peterson and Schwing, 2003

9. Modeled Gulf of Alaska coastal discharge Royer and Grosch

10. Changes in Ekman pumping Pre-shift mean conditions 1960-75 Dec-May Change after shift (1977-97) -(1960-75) Capotondi et al.

11. Outline The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Physical Ocean-Atmosphere Data Analysis Ocean Model Results: Coarse and Eddy-Permitting Bio-Geography: Samalga Pass Transition Point Paleo-Perspective: Isotopes and Archeology

12. Pycnocline (26.4) depth changesPeriod2 (77-97) – Period1 (64-75) P = OWS P G = GAK1 Model vs. Obs PAPA Model vs. Obs GAK 1980 1990 2000 1970 1980 1970 Capotondi et al.

13. Eddy-Permitting Model Eddy Surface Currents Before 76-77 Shift After 76-77 Shift Difference Kodiak Is. - More eddies north of Kodiak - Fewer eddies southwards Miller et al.

14. Naval Postgraduate School numerical model23 year (1979-2001) simulation with real winds NPS Model SST along shelf break Deep Salinity along shelf break Okkonen et al.

15. Physical-Biological Ocean Hindcast(Chai et al. model) Decrease in large zooplankton (and large phyto, small zoo) after the 1976-77 shift… …But occurs only during spring bloom Alexander et al.

16. Outline The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Physical Ocean-Atmosphere Data Analysis Ocean Model Results: Coarse and Eddy-Permitting Bio-Geography: Samalga Pass Transition Point Paleo-Perspective: Isotopes and Archeology

17. Locations of Passes sampled May-June 2002 Samalga Pass forms a boundary between shelf water to the east and open ocean waters to the west Coyle et al.

18. Surface Salinity along Aleutian Islands East of Samalga Pass, ACC has strong influence West of Samalga Pass, Alaska Stream has strong influence Ladd et al. (2004)

19. Abundance vs. Transect May-June 2002 Coyle et al.

20. Short-tailed shearwaters Seabirds Reflect Biogeographical Boundaries West of Samalga Pass: Fulmars and Auklets (open ocean food web) dominant East of Samalga Pass: Shearwaters and Puffins (coastal food web) dominant Northern fulmars Tufted puffins Small alcids Jahncke et al.

21. Outline The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Physical Ocean-Atmosphere Data Analysis Ocean Model Results: Coarse and Eddy-Permitting Bio-Geography: Samalga Pass Transition Point Paleo-Perspective: Isotopes and Archeology

22. Paleoproductivity 30 -20.0 20 -21.0 -22.0 10 -23 12 -24 10 -25 8 1700 1750 1800 1850 1900 1950 2000 Bering Sea: Skan Bay Core Paleoproductivity > 1976 Regime-shift Bering Sea: d13C - decrease Opal - variable Gulf of Alaska: d13C - increase Opal - increase d13C Opal (%) Gulf of Alaska: GAK 4 Core d13C GOA GAK 4 Opal (%) Skan Bay d13C Opal (%) Finney et al. Year AD

23. Relative Abundance of SSL based on Archaeological Data Maschner et al.

24. Some Outstanding Questions The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline What mechanisms control the restructuring of the ecosystem by climate, especially concerning fish? How do human activities and ecosystem interactions work with variable climate forcing to alter Steller sea lion populations? Do Steller sea lions feed in eddies? What can be said about changes in sub-surface conditions? How does vertical mixing vary in space and time? What other regime shifts may have occurred?

25. Synthesis Paper Highlights Title: The Climate-Ocean Regime Shift Hypothesis of the Steller Sea Lion Decline Forum: Fisheries Oceanography Authors: Trites, Maschner and all contributors Thesis: Spatial and temporal variations in the ocean climate system are creating adaptive opportunities for high trophic levels which is the underlying mechanism for the decline of the Steller sea lion populations in the western Gulf of Alaska. Important results: Temporal issue - 1970s to 1990s changes Spatial issue - East vs west asymmetry in Gulf of Alaska Biogeographic transition point at 170W Basin-scale climate changes have regionally sensitive impacts Upscaling from local complexities to broadscale regularities Eddy variance changes in western Gulf

26. Extras

27. Sea Surface Temperature Trends in the Gulf of Alaska (a) trend 1 • loadings increase west to east • warming from early 70’s • accelerated warming after 76 (b) trend 2 • accentuates trend 1 • pronounced drop after 58 • rapid rise after 72 • positive loadings = strong warming after 72 (c) trend 3 • strong warming in eastern GOA during 57-58 event • broad warming after 76 (d) trend 4 • strong interannual variability • impacts from El Niño events • strong loadings in coastal BC and WWD Bograd et al., 2004

28. NL PC1: 39% of variance Nonlinear PCA results from Marzan, Mantua, and Hare:based on 45 biotic indices from the Bering Sea and Gulf of Alaska for 1965-2001 NL PC2: 18% of variance

29. Kendall’s  trends in Alaska adult SSL data(Marzban, Mantua and Hare) 99% ci -- 99% ci -- For SSL data from 1970-2001

30. Seasonal Amplitude and Phase Changesin Coastal Freshwater Discharge Royer and Grosch

31. Wavelet Analysis of Coastal Freshwater Discharge Royer and Grosch

32. Naval Postgraduate School numerical model23 year (1979-2001) simulation with real winds Red line indicates shelf break (for Hovmuller diagram) Okkonen et al.

33. T and S vs. Transect May – June 2002 Coyle et al.

34. Schematic of Traditional Aleut Knowledge of Recent North Pacific Cycles Maschner et al.