Marine Mammals and Sound

Transcription

1 Marine Mammals and Sound

2 Acoustics Why sound? Light attenuates rapidly Sound travels farther & faster (higher density of fluid)

3 Over large spatial scales in water, visual communication is not practical but acoustic communication is

4 Acoustics What is sound used for? Feeding Communication Predator avoidance Navigation

5 Locating Food

6 Reproductive Display (Deception)

7 Obtaining Information About the Environment

8 Predation

9 Marine Mammal Acoustics How does sound function? - Basic wave form

10 Amplitude or Intensity Wave Form of Sound Transmission Frequency = cycles/sec = Hertz Wave length (λ) = speed/frequency Time

11 Characteristics of Sound High frequency = short 1 sec Low Frequency = long

12 Low Frequency Sounds Travel Farther Sound attenuates as a function of the # of cycles Low frequency: longer wavelength Travels farther for the same # of cycles

13 Characteristics of Sound High frequency = small Good for short range Good for long range Low Frequency = large

14 Describing Marine Mammal Sounds Frequency = pitch Amplitude = loudness (db) Duration

15 Amplitude Looking at Sounds Waveform/Power spectrum: Time (s)

16 Frequency (Hz or khz) Looking at Sounds Spectrogram/Sonogram: Amplitude denoted by color scheme Time (s)

17 Frequency (khz) Baleen whale song Song The production of a sequence of notes repeated in a predictable pattern Humpback, bowhead, blue, & fin whales 2 Humpback whale song 0 0 Time (s) 10 20

18 (khz) Baleen Whale Song 0.15 Blue whale 0.15 Fin whale (s) 75 (courtesy of Chris Clark) x 4x

19 Humpback Whale

20 Marine Mammals and Sound Pinnipeds Sound produced in the larynx Air-borne & underwater Low to high frequency Grunts, growls, mother-pup attraction calls, aggressive interactions

21 Weddell Seal Male Display

22 Steller sea lions: Males, females, & pups

23 Harbor Seal Male Low Frequency

24 Australian sea lion Mother and pup

25 Australian sea lion Mother and pup

26 Northern fur seal Mother and pup

27 Marine Mammals and Sound Odontocetes Sound produced by nasal passages Larynx present but no vocal cords Underwater vocalizations

28 Marine Mammals and Sound Odontocetes Mid to high frequency Biosonar: very high freq. (ultrasonic) Whistles, harmonics, clicks, upsweeps, etc.

29 Biosonar Broad frequency click trains

30 Beluga Whale

31 Narwhal

32 Killer Whale

33 Common Dolphin

34 Spotted & Spinner dolphins

35 Frequency Time Signature Whistles For identification and group cohesion Stable up to 12 years Common during separations

36 Frequency (khz) Signature Whistles Time (sec)

37 Marine Mammals and Sound Mysticetes Larynx present but no vocal cords Potentially use sinuses and/or vocal folds Underwater vocalizations

38 Marine Mammals and Sound Mysticetes Low frequency (infrasonic) Echo-ranging? Upsweeps, downsweeps, grunts, songs

39 Right Whales Multiple sound types Groans Trumpet Gun shot

40 Blue Whale Infrasonic = below human hearing (>20Hz)

41 Blue Whale Infrasonic x sec call

42 x5 x5 x10

43

44 Dwarf Minke Whale Mid to Low Frequency Sounds

45 Frequency (khz) Minke Whale (the star-wars vocalization, guitarfish, or boing-fish) Time (s) 2.5

46 Frequency (khz) Baleen whale song Song: The production of a sequence of notes repeated in a predictable pattern Humpback, bowhead, blue, & fin whales 2 Humpback whale Time (s)

47 Humpback Song Humpback and Fin whales: males sing to attract mates

48 Humpback Song Composed of: themes

49 Humpback Song Composed of: phrases

50 Humpback Song Composed of: sub-phrases

51 Humpback whales Only males sing observation & DNA All males sing same song, changes through time Why? male-male competition female attraction relay information synchronize estrous defend territory

52 Sound Surveillance System (SOSUS, Navy) For passive listening: - Submarines - Ships - Marine mammals

53 Estimating Geo-position

54 Tracking Whales SOSUS Arrays 1) Fin 2) Blue 3) Minke 4) Unknown

55 1) Fin 2) Blue 3) Minke 4) Unknown

56 Track of Blue Whale

57 Acoustics Uses of sound: Communication Reproduction Predator Avoidance Feeding Navigation

58 What happens when the ability to use sound is altered?

59 Noisy Ocean Earthquake Precipitation Jet engine 140 db Supertanker 190 db Earthquake 210 db

60 Man-Made Sounds Transportation Aircraft (fixed-wing & helicopters) Vessels (ships & boats) Hovercraft and vehicles on ice Dredging and Construction Dredging Tunnel Boring Other Construction Operations Oil & Gas Drilling and Production Drilling from Islands Drilling from bottom mounted platforms Offshore oil & gas production Geophysical Surveys Airguns Sleeve Explosions and Gas Guns Other Techniques Sonars Explosions Ocean Science Studies Seismology Acoustic Propagation Acoustic Thermometry