Steller Sea Lion Critical Habitat

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Steller Sea Lion Critical Habitat

• Dr. Randall Davis
• Texas AM Univ.
• Mr. Don Calkins
• Alaska SeaLife Center
• Ms. Holly Briggs
• Texas AM University

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Collaborators

• Mr. Jason Waite
• Alaska SeaLife Center
• Dr. Robert Leben
• The Colorado Center for Astrodynamic Research,
  University of Colorado, Boulder

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What is Critical Habitat?

• Critical habitat is defined in the US Endangered
  Species Act as
• (i) the specific areas within the geographic
  area occupied by the species, at the time it is
  listed in accordance with the provisions of
  section 4 of this Act, on which are found those
  physical or biological features (I) essential to
  the conservation of the species and (II) which
  may require special management considerations
  and
• (ii) specific areas outside the geographic area
  occupied by the species at the time it is listed
  in accordance with the provisions of section 4 of
  this Act, upon the determination by the Secretary
  that such areas are essential for the
  conservation of the species.

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Critical Habitat StudyCritical habitat definition

• 1992 Recovery team
• Recommended 3 aquatic foraging areas
• Aquatic areas 3000ft seaward of rookeries and
  major haulouts
• 1993 NMFS
• Designate 3000ft zones seaward, landward and
  upward of all rookeries and haulouts in Alaska
  and seaward and upward of all rookeries in CA and
  OR
• Designated 20 nm zones seaward of all rookeries
  and major haulouts west of 144o

Courtesy National Marine Fisheries Service
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Critical Habitat Designation
Courtesy National Marine Fisheries Service
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What habitats are critical?What do we know?

• Adult females at rookeries forage predominately
  within 20 nm of rookeries while attending pups
  June to November.
• Weaned juveniles and adult females move around a
  great deal and may forage as far as 500 km
  offshore. They utilize areas out to the
  continental shelf.

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Critical Habitat StudyObjectives

• 1. To monitor Steller sea lion movements and
  diving behavior using satellite telemetry
• To characterize Steller sea lion habitat
  associations by combining tracking and dive data
  with bathymetry, and TOPEX/POSEIDON and ERS
  satellite remote sensing of hydrographic
  features.
• To compare areas shown to be important or
  critical to sea lions in this study to those
  areas currently protected as designated critical
  habitat by NMFS.

Photo by J. Waite
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Critical Habitat StudyMethods

• Capture sea lions
• Dart Capture
• Hoop net capture
• Dive Capture
• Floating trap
• Bring aboard boat and anesthetize

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Critical Habitat Study

• Sample captured animals
• Blood
• Tissue biopsies
• Blubber
• Skin
• Flipper punch
• Tooth
• Nasal, oral and genital swabs
• Muscle

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• Glue on Transmitters
• SLOT
• Glued to head
• Transmissions limited to surface times

Photo by R. Davis
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Critical Habitat Study

• Glue on Transmitters
• SDR

Photo by J. Waite
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Critical Habitat Study

• Release
• Animal allowed sufficient time to recover from
  anesthesia
• Released back into area of capture

Photo by J. Waite
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Data collection

• Monitoring
• Service ARGOS System
• 2 sun-synchronous Polar orbiting TIROS-N Weather
  Satellites
• Three consecutive UHF transmissions from the tag
• Location calculated by Doppler shift of tag
  transmissions created by the speed of the
  satellite
• Accuracy depends on number and time between
  received messages during the satellite pass
• Previous 6 hours of dive data transmitted each
  time

Polar orbiting satellites carrying receivers
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Argos System Satellite Telemetry
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Critical Habitat Study
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Critical Habitat Study

• Location data will be plotted and compared to
  hydrographic features
• Bathymetry
• 4 categories
• Continental shelf
• Upper continental slope 200 1,000 m
• Lower continental slope 1,000 to 2,000 m
• Abyssal 2,000m

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Critical Habitat Study

• Comparisons to hydrographic features continued
• Sea Surface Height Anomaly
• Anticyclone (warm-core) eddies
• Cyclonic (cold-core) eddies
• Confluence
• other

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Critical Habitat Study

• What have we done?
• Applied for Permit
• Purchased equipment
• Capture Skiff
• Dive Equipment
• Dive skiff
• Satellite Transmitters
• Received and prepared