The Examination of killer whale (Orcinus orca) call duration due to boat noise and vessel count

By: Peter Valenzuela

Beam Reach Spring 2009

Introduction

• There are 3 different Ecotypes of Killer Whales:– Offshore: Thought to be fish/shark Eating– Transients: Mammal Eating – Residents: Fish Eating

• The Southern Resident Killer Whales (SRKW) are our focus of study

• Area of Study: San Juan Islands and Haro Strait

• Three Major Threats to Killer Whales:– Toxins, Prey Availability, and Noise

Killer Whales and Sound

• Sound is primary source of communication between the SRKW

• Extra human noise potential to disrupt SRKW normal activities

• John Ford Classified 3 types of Sounds: clicks, whistles, and pulsed calls

• Pulsed calls are most abundant and characterized class of vocalization used by the SRKW

S1 Call

Other Studies done on Call Duration

• Andrew Foote: Boat Presents or Absence- found significance in call duration to boat presence

• Marla Holt: Measured boat noise to see if it affects call duration- found no significance

Methods• Looked for behavior states

– Traveling, Resting, Milling, Foraging, Play

• Counted boats (within .5 Nautical mile or approximately 1000 meters)

• Measured Boat noise• Used Audacity program for

analysis

Spectrogram in Audacity

Spectrogram in Audacity con.

Results

• P-value: 0.000718 & Sample Size: 181

All: Call Duraton (sec) VS Vessel Count

y = 0.0173x + 1.1215

R2 = 0.0599

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 2 4 6 8 10 12 14 16

Vessel Count

Call Duration (sec)

Series1

Linear (Series1)

• P-value: 0.485

All: Call Duration (sec) VS dB re 1 microPa

y = 0.0041x + 0.6928

R2 = 0.0037

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

110.00

112.00

114.00

116.00

118.00

120.00

122.00

124.00

126.00

128.00

dB re 1 microPa

Call Duration (sec)

Series1

Linear (Series1)

• P-value < 0.001

All: Vessel Count VS dB re 1 microPa

y = 5.3076x + 117.19

R2 = 0.2383

110.00

112.00

114.00

116.00

118.00

120.00

122.00

124.00

126.00

128.00

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

Vessel Count

dB re 1 microPA

Series1

Linear (Series1)

Comparison

• Andrew Foote (n=135)– Found Significance

using a Mann Whitney U test between boat presence/absence and Call duration

• Peter Valenzuela (n=181)– Did same test and

found no significance

• Marla Holt (n=104)– Found no

significance using a linear regression between boat noise and call duration

• Peter Valenzuela (n=181)– Found Significance

using the same test, but varies by behavior

Behavior Breakdown!

P-Value Traveling Foraging Play

CD vs VC 0.00013 0.644 0.147

CD vs BN 0.0153 0.434 0.234

VC vs BN < 0.001 0.0075 0.329

Sample Size

127 31 23

Thank You!

• Beam Reach– Dr. Jason Wood– Dr. Val Veirs– Dr. Scott Veirs

• Cpt. Todd Shuster• Cpt. Mike Kramer• My Class Mates

Questions?