Localizing Vocalizations in fish- eating southern resident killer whales (Orcinus orca) Peggy...
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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