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 BasicsOnly member of EschrichtiidaeFeeding generalistsTwo populations in North Pacific: ENP & WNPENP 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.*)

ENP Gray Whale Range

Rugh’s ObservationsShift in migration timing - PDO

Census @ Granite Canyon since 1967Median 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]

Perryman’s Observations-sea ice = +recruitment

Our Observations

Pt. Piedras Blancas, CA

Absence of Feeding GW in the Chirikov Basin…

Co-incident with Decline in Infaunal Benthic PreyJ. Grebmeier’s Benthic Time Series

So, if not the Chirikov Basin, where are Gray 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, 1999-2004

100s of whales in 2000 & 2001

Feeding on dense swarms of cumaceans

Benthic sampling from small boat,

15-20 August 2002Jackie ClementExtremely high cumacean densities @ 4 stations: 48,000-86,000/m2

Amphipods nearly absent

Meanwhile, Recorders Near Barrow

ARPs deployed OCT03-SEP04,via NSF-SBI cruisesPart of broader AK array; BioScience, January 2006

With thanks to:L. Munger (SIO) R. Pickart (WHOI)

Detect Gray Whale Callsthroughout winter `04 [until May]

AVHRR sea ice image: 25 January 2004

‘breathing room’ [image: Hajo Eiken]

Sea Ice and Productivity: Conceptual models

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 GoalsInclusion 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