Localizing Vocalizations in fish-eating southern resident killer

whales (Orcinus orca)

Peggy ForemanBeam Reach 2006

Marine Science and Sustainability School

Social Arrangements

• Pod- primary social unit of matrilineal groups•Subpods and matrilines (J, K, and L)

• Communities- frequent associations with one or more pods, yet have different distributions with other communities (J + K + L)

• Clans- acoustically related; shared vocal tradition (J clan)

Vocal Clans

• Complex repertoire of whistles, clicks, and calls

• Calls are pulsed signals generated in high repetition rates and most fall into discrete categories

• These discrete calls are the most common sound type when individuals are widely spread out (cohesion)

Gender

• 86 whales (~14 sexually mature males and ~23 reproductive females)

• Sexual dimorphism • Predict lower frequency fundamental for males

• May spatially segregate to some degree when foraging

• Shorter duration of calls• Changes in harmonic frequency

Questions

• Are there any variations in calls in regards to gender?

Call Characteristics:

Call duration, Fundamental Frequency, and variations in the first harmonic of a call

* Towed linear 4 hydrophone array

* National Instruments Board with 4 channels

* PC computer: Ishmael software to localize calls

Raven software to analyze calls

* Clipboard: PDA/data sheets (behavioral data)

* Binoculars

* Range finder (research assistant)

* Camera (research assistant)/ID guides

Materials

Methods

• Hydrophone array was deployed off the starboard steps

• Continuous Acoustic Recording in Ishmael (sampling rate of 22050, DFT rate 512)

• Behavior Data ( # focal animal/s, distance, bearing, and predominant group behavior state)

• Opportunistic lone individuals or small groups (increase my success in localizing)

Acoustic Analysis:

ISHMAEL• Software designed to localize

• Phone pair bearing, crossed-pair bearing, hyperbolic location, and beam forming

• 0°, 180° can’t get a valid bearing (15°)

• Dinghy experiment: accurate with in 17° and closer than 300m to the boat worked best

• calculates two bearings

Acoustic Analysis:

ISHMAEL

Raven Analysis:

Call Characteristics

Duration

Fundamental

1st Harmonic Analysis (low, high, and change in Frequency)

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Results:

• Acoustic and surface behavior observations were recorded on 6 out of 19 field days

• 19.5 hr of acoustical recordings and 16.95 hr of PDA data (1170 one minute files)

• Looked through 115 one minute files

• Localized 122 calls

• 19 of those localized calls matched my bearing (avg 5.8° difference)

Results:

J “sprouter”

K21

1 call

3 calls

Foraging

SD Travel

L47

J-juvenile

2 calls

1 call

SD Travel

SD Travel

2M/2F (L21/L47)

1M/2F/J (K40)

4 calls

8 calls

SD Travel

SD Travel

SD= slow directional

Results:

Average Fundamental of Calls

0

200

400

600

800

1000

1200

1400

1600

Males Females Mixed

Gender

Frequency (Hz)

ANOVA: F[2,16]=2.4212, p= 0.1206

4 3 12

95% confidence intervals

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Average Call Duration

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Males Females Mixed

Gender

Time (sec)

Results:ANOVA: F[2,16]=1.8183, p= 0.1943

3 124

Results: 1st Harmonic

Average Low Frequency of Calls

0

500

1000

1500

2000

2500

3000

3500

4000

Males Females Mixed

Gender

Frequency (Hz0

ANOVA: F[2,16]=0.4785, p= 0.6283

3 124

Results: 1st Harmonic

Average High Frequency of Calls

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Males Females Mixed

Gender

Frequency (Hz)

ANOVA: F[2,16]=1.2457, p= 0.3142

3 124

Results: 1st HarmonicANOVA: F[2,16]=3.5752, p= 0.0521

312

4

Average Change in Frequency of 1st Harmonic of Calls

-500

0

500

1000

1500

2000

2500

3000

Males Females Mixed

Gender

Frequency (Hz)3 124

Discussion

Call Characteristics

My predictions Results

Fundamental Frequency

Lower for males

Higher for males and mixed

Call DurationShorter for males

Shorter for males

Changes in

1st Harmonic

They would be different

∆F: males higher, *mixed

Discussion

• Real differences between gender and mixed groups?

• Analyzed calls: Different call types?

• Males and Females could be using different calls

• The frequency Modulation changes with mixed gender groups could that be due to group size?

• Variations due to more than one pod together?

Why is this important?

• Localizing is only one piece of the larger picture

• Who is speaking…is it the oldest matriarch …is it the male on the periphery

scouting out “good” foraging areas • Acoustically recognize individuals

- especially in winter- detect when additions or loss of individuals

occur in the population

Future Studies

• Full summer season to see if changes in calls change with location, behavior, different social organizations

• Calling rate

• Source level of calls

• Call type vs. surface behavior

• Do males and females use the same discrete calls (vary with age?)

Acknowledgements

• Huge thank you to the instructors of Beam Reach(Jason Wood, Donna Hauser, Scott Veirs, and Val Veirs)

• Beam Reach colleagues (Rena Escobedo, Emily Pierson, Erin Soucy, Colleen Barry, and Juliette Nash)

• Todd, Mike, Glenn for the use and safe navigation of the Gato Verde

• Puyallup Tribe of Indians for your financial support

• Dr. James Ha for creating my specialized PDA program