Environmental Variability, Bowhead Whale Distributions and Iupiat Subsistence Whaling

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Environmental Variability, Bowhead Whale
Distributions and Iñupiat Subsistence Whaling
Carin Ashjian (Woods Hole Oceanographic
Institution)
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Who are we?

• Modelers
• Wieslaw Maslowski (NPS)
• Yvette Spitz (OSU)

• Oceanographers
• Carin Ashjian (WHOI)
• Robert Campbell (URI)
• Steve Okkonen (UAF)
• Barry Sherr (OSU)
• Ev Sherr (OSU)

• Social Scientists
• Steve Braund (SRBA)
• Jack Kruse (UMassAmherst)
• Craig Nicolson (UMassAmherst)

• Whale Ecologists
• Craig George (NSBDWM)
• Sue Moore (APL)

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Bowhead whales are found on the shelf along
northern Alaska during their fall migration and
are hunted there
Barrow
Kaktovik

• Why do whales prefer certain locations along the
  shelf?
• How might climate variability affect this
  behavior?
• How might climate variability affect whaling
  success?

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We think that whales stop at Barrow to feed
because there are high concentrations of plankton
prey here

• Plankton composition (copepods or
  euphausiids/krill) is influenced by amount of
  Pacific Water
• Euphausiids/krill come to this region in Pacific
  Water
• Plankton patches are formed at fronts in the
  ocean or at places where there is a lot of food
  for the whale prey

Euphausiids/Krill
Copepods
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How does the amount of Pacific Water vary?Two
Climate Regimes

• Regime I (negative AO, strong Beaufort gyre)
  Greater influence of Beaufort Sea gyre near shore
  and Arctic water, less PW
• Regime II (positive AO, weak Beaufort gyre)
  More PW extending along Beaufort Shelf (contains
  euphausiids)

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GOALS OF OUR PROJECT

• To describe why bowhead whales stop at Barrow
  during their migration
• To describe the oceanographic conditions that
  make this a good place for food
• To understand how climate variability might
  change the locations of good feeding spots when
  the whales are near Barrow

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How will we do this?

• Biological-physical modeling of the ice-ocean
  system
• High resolution field study of the coastal ocean
  to identify the oceanographic conditions leading
  to plankton prey patches and to verify model
  predictions
• 20-year retrospective analysis of climate, ocean
  conditions, plankton and whale distributions, and
  hunting success
• Ground-truthing of the analyses and integration
  of expert local knowledge through interaction and
  involvement of whaling captains

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How will we do this?

• Biological-physical modeling of the ice-ocean
  system
• High resolution field study of the coastal ocean
  to identify the oceanographic conditions leading
  to plankton prey patches and to verify model
  predictions
• 20-year retrospective analysis of climate, ocean
  conditions, plankton and whale distributions, and
  hunting success
• Ground-truthing of the analyses and integration
  of expert local knowledge through interaction and
  involvement of whaling captains

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High-resolution field sampling

• This is the kind of boat we will use
• We would work from mid-August to mid-September
  (if we need to)
• We will sample in both 2005 and 2006

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High-resolution field sampling the locations

• We will go out for 1-2 days at a time and come
  back to Barrow in between
• Exact locations of transects to be determined
  after discussions with whaling captains
• We need your help to identify the locations of
  our sampling

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Field Sampling

• DISCRETE (AT STATIONS)
• CTD and Rosette - T, S, Fl, PAR, nutrients,
  phytoplankton and microzooplankton abundance and
  composition, chlorophyll a
• Video Plankton Recorder -high resolution vertical
  distributions of plankton
• Plankton net tows - zooplankton composition and
  plankton condition

• UNDERWAY
• ADCP - velocity and backscatter (plankton)
• CTD and fluorometer mounted on Acrobat towed
  undulating vehicle
• Bottom depth (ships fathometer)

• OTHER (DURING WHALING)
• Whale strike locations
• Boat towed CTDs (fronts, eddies, whales)
• Whale stomach content analysis (plankton type)
• Whale locations (aerial surveys)

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Acrobat towed undulating vehicle
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In-situ plankton type and abundance using a video
plankton recorder

• Underwater microscope
• Images of plankton are captured at 60 times per
  second and saved on an internal hard drive
• Coincident temperature, salinity, and depth
• Once back on board, the files are downloaded from
  the instrument

Video Camera and Strobe
CTD
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Shore Based Work

• Sampling program based at BASC and will use
  laboratory and storage facilities there
• Some laboratory analyses will be done here other
  samples will be shipped home
• We will present our initial findings in September
  before we leave we will come back in winter to
  show more.

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