Killer Whale Vocal Response to Vessel Traffic

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Killer Whale Vocal Response to Vessel Traffic

• Celia Barroso
• Beam Reach Marine Science and Sustainability
  School
• Fall 2005
• California State University, Long Beach
• Long Beach, California

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• Southern resident killer whales (SRKW) declared
  depleted under the Marine Mammal Protection Act
• Possible causes according to NOAA/NMFS
  Conservation Plan
• Pollutants/Contaminants (c.f. PCB, DDT)
• Decreased prey availability
• Anthropogenic noise pollution

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Population Structure and Communication

• Different pods (J-pod, K-pod, and L-pod)
• Different dialects
• Pod specific calls (Ford, 1990)
• S1 (J-pod, K-pod)
• S16 (K-pod, L-pod)
• S19 (L-pod)
• Dominant calls

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Research that sparked my curiosity

• Vessel traffic has increased five fold over
  between 1990 and 2000 (Foote et. al., 2004)
• During the period of 2001-2003 all pods exhibited
  a significant (15) increase in call duration in
  the presence of whale-watching vessels.

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My questions

• Do SRKWs exhibit short-term changes in call
  duration in response to daily exposure to vessel
  noise?
• Do they modify their calls to avoid masking by
  boat noise?
• Examples motor , ship , quiet

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How did I conduct my experiment?

• I attempted to recreate Andrew Footes and
  Richard Osbournes published research over a
  shorter time scale.
• We used a hydrophone, amplifier and digital
  recorder to receive and record the sounds.
• Viewed spectrograms of S1, S16, and S19

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How did I conduct my experiment?

• Calculated call duration of the second harmonics
  for S1 and S16 calls, the third harmonic for S19
  high frequency component and fundamental for low
  frequency component

S1
S19 Low
S19 High
S16
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What did I find?

• The mean I calculated for S16 calls compares to
  the mean S16 call published by Foote et. al.
• I did not record S16 or S19 calls that were
  quantifiable using my methods when vessels were
  absent

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What did I find?

• Average S1 call duration in the presence of
  vessels is 1.17s and 1.105s in the absence of
  vessel noise.

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What did I find?

• No trends

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Problems and conclusions

• I, unlike Foote et al., was generally unable to
  distinguish which pod I was listening to
• More observations are needed
• Observations during peak whale-watching season
• 24hr observations
• Observations regarding activities and call
  duration
• Perhaps SRKWs dont modify their calls in
  response to vessel noise

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