1. Thursday: 03/20/2014
Go to: Kahoot.it Pin is: 1581 Enter Your Name

2. Thursday: 03/20/2014
Each individual must answer the following questions in complete sentences:
Sketch and label, or describe the flow of air & sound when a small cetacean uses echolocation to find prey.
Describe four major physiological adaptations that deep-diving cetaceans have to dealing with high pressure.
What are the four modern whaling countries and what justification is used by each for this illegal practice (not all answers will be found in the notes)?
What are two major differences between mysticeti and odontoceti? Give an example of each animal.
Explain the conservation laws that were passed in 1911, 1972, and 1985.

4. Acoustics and Biology Acoustics loudness (amplitude or pressure level)
pitch (frequency)
Use of sound by marine animals
Predation/defense
Communication and social interaction

5. 
Same frequency,
Different amplitude
Same amplitude,
Different frequency
Amplitude determines sound level pressure or loudness
Frequency determines “pitch”

6. Loudness
(Amplitude, sound level)
Chart shows loudness in dB of some things we are familiar with
Sound levels in air and water have different reference levels, so
0 dB (air) ≈ 26 dB (water)

7. Marine animal sounds can be made up of multiple frequencies
The sound spectrum gives the pressure level at each frequency
Intensity  pressure2
dB = 10 Log10(intensity)

8. Spectrogram shows how sound spectrum changes over time

9. An invertebrate example:
snapping shrimp
claw crab
Snapping shrimp make noise to stun their prey.
They create a cavitation bubble that “snaps” as it collapses.

10. A fish example: Atlantic Croaker
Some fish use sound for courting and as a fright response

11. Toothed whales Baleen whales Smaller (1.5 to 17 m long) Social
Most are not migratory
Chase and capture individual fish, squid, crabs
Use sound to echolocate, communicate
Baleen whales
Larger (15 to 30 m long)
Often solitary
Long annual migrations
Feed on aggregations of krill, copepods, small fish
Use sound only to communicate

12. Baleen
(mysticete)
whales
Toothed
(odonticete)
whales

14. Larger whales produce lower-frequency sound
Larger whales can dive deeper
Toothed whales forage deeper than baleen whales

15. Outgoing sound is generated by the vocal cords and projected through the melon.
Incoming sound is received through the jaw, which transmits sound waves through a fat channel to the “ear” (auditory bulla).

16. Social calls Frequency (Hz)
Dolphins live in social groups that stay together 5-10 years. They have “signature whistles” that can be used to recognize individuals at distances of >500 m.
Time (s)

17. Communication frequencies
Toothed Baleen
Thick bars: most common vocalizations
Thin lines: extremes of frequency

18. Echolocation using echoes from sound pulses or clicks
Whale can determine distance, angle, size, shape, etc. from sound echoes

19. Echolocation frequencies
Mellinger 2007

20. Toothed whale prey Baleen whale prey Squid and large fish are:
More likely to be solitary
Good acoustic targets
(squid pens and fish swim bladders have density different from water)
Plankton are:
More likely to aggregate
Poorer acoustic targets
(density similar to water)
Baleen whale
prey

21. A good invention for listening to whales: acoustic whale tag (D-Tag)
Acoustic sensors (hydrophones) and 3D accelerometers in a waterproof, pressure-resistant case, mounted on suction cups
Carefully sneak up on whale, attach D-Tag
Record audio, pitch, roll, heading and depth
Tag pops off, floats to surface 18 hours later
Mark Johnson with D-Tag

22. Long-Term Geotags:

23. Toothed whale foraging: Beaked whales dive deep to find prey
Natacha Aguilar de Soto
(Yellow indicates echolocation)
Peter Tyack et al.

24. Baleen whale foraging: Right whales dive to bottom of the mixed layer where plankton are most concentrated
Fig. 4. Eubalaena glacialis and Calanus finmarchicus. (a-d) Examples of diving and tracking observations during feeding behavior. Contoured C. finmarchicus C5 abundance estimated from the OPC casts is shown. Color scale shown in (d) applies to all plots. () Times of visual contacts.
() Times and locations at which a resurfacing occurred and a conductivity-temperature depth/optical plankton counter (CTD/OPC) cast was conducted. Solid and dashed lines indicate the sea floor and the top of the bottom mixed layer, respectively, measured at the location of each CTD/OPC cast.
Baumgartner and Mate 2003

25. Marine mammal sound levels are generally between 100 and 200 dB
Baleen whales
Toothed whales
Seals, sea lions, and walruses
Manatees and dugongs
Echolocation (toothed whales)

26. Worcester & Spindel 2005

27. Blue whales migrate and communicate over long distances

28. Man-made noise in the ocean
These add constant background noise
Outboard engine
6,300 Hz
Commercial Ship
10 to 20,000 Hz
Airgun
10 to 500 Hz
Up to 232 dB
Low-Frequency Active Sonar
100 to 500 Hz
230 to 240 dB
These are loud enough to damage tissues and cause hearing loss

29. Humans add noise to the ocean
Potential effects of man-made sounds on marine mammals:
Temporary or permanent hearing loss or impairment
Disruption of feeding, breeding, nursing, acoustic communication and sensing
Death from lung hemorrhage or other tissue trauma
Psychological and physiological stress

30. Since the invention of propeller-driven motors (~150 years ago),
Background noise level in the ocean has increased by ~45 dB
Lowest background noise f has dropped from ~100 Hz to ~7 Hz
After motors
~7 Hz
Before motors
~100 Hz
After motors
~75 dB
Before motors
~30 dB

31. Can use transmission-loss curves to calculate the effective communication range
Blue whale song
20 Hz, ~155 dB
Pre-motor noise level
30 dB
Whale song stays
above ambient noise
level for ~2,000 km
e.g. San Diego to Seattle
(area 10,000,000 km2 )
Current noise level
75 dB
level for ~60 km
e.g. New Brunswick to NYC
(area 10,000 km2)
Blue
whale

32. Range of effective communication for blue whale
singing at 20 Hz and 155 dB
Range before
mid-1800s
Current range

33. Noise-induced mass strandings
Mass strandings associated with Navy sonar activity
The Bahamas (2000):
14 beaked whales, 1 spotted dolphin, 2 minke whales
Cranial Bleeding
Naval Training Exercise: SONAR
The Canary Islands (2002):
14 beaked whales
Gas bubbles and bleeding in multiple organs, likely from surfacing too quickly

34. Noise-induced mass strandings
Mass strandings associated with air guns
Tasmania and New Zealand (2004):
208 whales and dolphins
Mass Stranding: ExxonMobile Seismic Testing
Senegal and Madagascar (2008):
200 pilot whales and melon-head whales
Mass Stranging: Dolphins & Seismic Testing
Northern Peru (February 2012)
900+ dolphins stranded or washed ashore dead
Middle Ear Bleeding
Cracked bones in ear
Hemorrhage in mandibular fat
Air bubbles in liver, kidneys, bladder, and blood vessels
Pulmonary emphysema
* The last two are associated with acute decompression syndrome