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Gray Whales as Sentinels of Alaskan Ecosystem Variability. Sue E. Moore NOAA/AFSC @ APL-UW. Co-Investigators. Kate Stafford (APL-UW) Kate Wynne (UAF – Kodiak) Jackie Grebmeier (UT) Dave Rugh (NOAA/AFSC/NMML) Wayne Perryman (NOAA/SWFSC/PRD) Jim Overland (NOAA/PMEL). Gray Whale Basics.
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Gray Whales as Sentinels of Alaskan Ecosystem Variability Sue E. Moore NOAA/AFSC @ APL-UW
Co-Investigators • Kate Stafford (APL-UW) • Kate Wynne (UAF – Kodiak) • Jackie Grebmeier (UT) • Dave Rugh (NOAA/AFSC/NMML) • Wayne Perryman (NOAA/SWFSC/PRD) • Jim Overland (NOAA/PMEL)
Gray Whale Basics • Only member of Eschrichtiidae • Feeding generalists • Two populations in North Pacific: ENP & WNP • ENP pop. ~ 18K whales *de-listed in late 1992 **1999-2000 mortalities, post 1997-98 El Nino
Ecosystem Sentinels?‘Weight of Evidence’ • One-week delay in southbound migration timing, coincident with NPAC regime shift (Rugh et al. 2001) • Calving rates positively correlated with ice-free Chirikov Basin (Perryman et al. 2002) • Absence of feeding GW in Chirikov Basin,coincident with decline in benthic infauna (Moore et al. 2003) • Feeding whales year-round near Kodiak(Moore et al.*) • Calls detected year-round near Barrow(Stafford et al.*)
Rugh’s ObservationsShift in migration timing - PDO • Census @ Granite Canyon since 1967 • Median Southbound dates: • 8 JAN pre-1980 • 15 JAN post-1980 • 1-week shift, co-incident with increase in calf sightings North of Mexico (Shelden et al. 2004) [PDO = N. Mantua]
Co-incident with Decline in Infaunal Benthic PreyJ. Grebmeier’s Benthic Time Series
So, if not the Chirikov Basin, where areGray Whales Feeding? • 10s to 100s of whales seen feeding year-round offshore Kodiak Island K. Wynne’s surveys • ‘many’ west of the IDL in Southern Chukchi Sea • 10s to 100s reported NE Barrow by whalers • 10s of whales feeding near Sitka J. Straley obs.
‘Kodiak’ Gray Whales, 1999-2004100s of whales in 2000 & 2001
Feeding on dense swarms of cumaceans • Benthic sampling from small boat, 15-20 August 2002 Jackie Clement • Extremely high cumacean densities @ 4 stations: 48,000-86,000/m2 • Amphipods nearly absent
Meanwhile, Recorders Near Barrow • ARPs deployed OCT03-SEP04,via NSF-SBI cruises • Part of broader AK array; BioScience, January 2006 With thanks to: L. Munger (SIO) R. Pickart (WHOI)
AVHRR sea ice image: 25 January 2004‘breathing room’ [image: Hajo Eiken]
K. Wynne’s - ‘So What?’ • Gray whales are not behaving “like they used to”; is it just population growth/recovery? • Gray whales track prey shifts and thereby provide insight to local ecology. [Duffus Lab] • Population & environmental time series supports modeling approach. [J. Brandon] • Species should be considered NPAC/Arctic Ecosystem Sentinel – under development by NOAA Ecosystem Goal Team [S. Swartz]
Ultimate Goals • Inclusion of gray whales (& other large whales) in Ecosystem Models. • Capability to interpret Ecosystem Variability via population and health assessment of large whales. • Improved prediction/response to mortality events.
THANKS for Support • NOAA/AFSC/NMML: GW census, aerial surveys, Kodiak prey assessment & ARPs (via Scripps) • NOAA/SWFSC: calf census, aerial surveys, sea ice analyses • NOAA/PMEL: conceptual model & web support • UAF/GAP Program: Kodiak logistic support • NSF/Shelf-Basin-Interaction Program: logistic support for Beaufort recorders