Steller Sea Lion Critical Steller Sea Lion Critical HabitatHabitat

Dr. Randall DavisDr. Randall DavisTexas A&M Univ. Texas A&M Univ.

Mr. Don CalkinsMr. Don CalkinsAlaska SeaLife CenterAlaska SeaLife Center

Ms. Holly BriggsMs. Holly BriggsTexas A&M UniversityTexas A&M University

CollaboratorsCollaborators

• Mr. Jason Waite– Alaska SeaLife Center

• Dr. Robert Leben– The Colorado Center for Astrodynamic

Research, University of Colorado, Boulder

What is Critical Habitat?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.”

Critical Habitat StudyCritical Habitat Study

Critical habitat definitionCritical 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

Critical Habitat DesignationCritical Habitat Designation

Courtesy National Marine Fisheries Service

What habitats are critical?What habitats are critical?What do we know?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.

Critical Habitat StudyCritical Habitat Study

ObjectivesObjectives

• 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

Critical Habitat Study

MethodsMethods

• Capture sea lions1. Dart Capture

2. Hoop net capture

3. Dive Capture

4. Floating trap

• Bring aboard boat and anesthetize

• Sample captured animals– Blood – Tissue biopsies

• Blubber • Skin• Flipper punch• Tooth• Nasal, oral and genital

swabs • Muscle

Critical Habitat StudyCritical Habitat Study

• Glue on Transmitters

– SLOT• Glued to head• Transmissions limited

to surface times

Photo by R. Davis

• Glue on Transmitters

– SDR

Photo by J. Waite

Critical Habitat StudyCritical Habitat Study

Critical Habitat StudyCritical Habitat Study

• Release– Animal allowed

sufficient time to recover from anesthesia

– Released back into area of capture

Photo by J. Waite

Data collectionData 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

Argos System Satellite Telemetry

FORRESTER IS

DALL ISLAND

30 0 30 60 90 120 Kilometers

N

EW

S

90 % MCP Homerange

Critical Habitat StudyCritical Habitat Study

Critical Habitat Study

• Location data will be plotted and compared to hydrographic features:

– Bathymetry• 4 categories

1. Continental shelf <200 m

2. Upper continental slope 200 – 1,000 m

3. Lower continental slope 1,000 to 2,000 m

4. Abyssal >2,000m

Critical Habitat StudyCritical Habitat Study

• Comparisons to hydrographic features continued– Sea Surface Height

Anomaly1. Anticyclone (warm-

core) eddies

2. Cyclonic (cold-core) eddies

3. Confluence

4. other

Critical Habitat Study

• What have we done?– Applied for Permit– Purchased equipment

• Capture Skiff• Dive Equipment• Dive skiff • Satellite Transmitters

– Received and prepared