Marine Mammal Sensory & Sound Production Systems MARE 390 Dr. Turner

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  • Marine Mammal Sensory & Sound Production Systems

    MARE 390Dr. Turner

  • SoundProduction, transmission, & reception of sounds produced by marine mammals unique airborne & waterborne

    Manner differs between taxa & media

    Purposes: Communication within species to location of unseen targets with echolocation

  • Sound PropagationAcoustic energy characterized by velocity, frequency, wavelength, & amplitude

    Human hearing 18 Hz to 15kHzMarine mammal vocalizations above & below

    < 18 Hz (infrasonic)> 20 kHz (ultrasonic)

  • Sound in Air & WaterSound travels 5X faster in water (1550m/s) than air (340m/s) depending upon temperature & salinity (depth)

    Why increased capacity for sound production?

    Poor light transmission & vision in water

  • Functions of SoundDolphins large variety of whistle-like sounds; can understand complex linguistics

    Many sounds used for communicationSignature calls identify individuals

    Loud impulse sounds debilitation of prey, self-defense, intimidation of conspecifics

    Echolocation active detection & identification of a target with sound

  • Acoustic SignalFrequency, duration, & energy level are portrayed as:Spectrogram (frequency with time)

    Power spectrum (sound pressure levels with time)

    Frequency spectrum (sound pressure levels with frequency)

  • Acoustic SignalSpectrogram (frequency with time)

    Power spectrogram(sound pressure levels with time)

    Frequency spectrum (sound pressure levels with frequency)

  • Use of SoundsLow frequency sounds attenuate more slowly so good for long distance communication

    High frequency sounds attenuate more quickly but have the potential to provide more information on target resolution

  • Mammalian EarEvolved for detection of sound vibrations in air

    Amplitude (loudness) determined by the number of hair cells stimulated

    Frequency (pitch) depends upon the distribution pattern of stimulated hair cells

  • Pinniped Sounds Sounds produced 1 with larynx

    2 - teeth & pharyngeal pouches

    Typical mammalian ear with modificationsamplify sound receptionengorged with blood during diving

  • Cetacean Sounds Nasal sacs ventral to blowhole produce sounds including whistles & echolocation

    Monkey-lips or Phonic lips produce sounds as air is forced through themtweaking end of air-filled balloon

  • Cetacean Sounds

  • Sperm Whale Head

  • Sound PropagationMelon contains low-density lipids which serve as an acoustic lens to create focused directional sound beams

  • Mysticete RhythmsMysticete larynx possesses structures homologous to vocal folds - are capable of sound generation

  • Mysticete Rhythms(U-fold) in the lumen of the larynx- vibration of edges may generate sounds- walls of the laryngeal sac can serve as a resonant space

  • Sound ReceptionAll cetaceans have good hearing

    Auditory canal narrow in odontocetes; plugged in mysticetesGlove finger projection of eardrum into ear canal

  • Odontocete ReceptionUnique sound reception pathway jaw

    Pan Bones - Posterior portions of mandibles, flared, thin to transparency

    Filled with low density lipid similar to melon

    Directly connects with the auditory bulla of the middle ear

  • Odontocete Reception

  • Other Marine MammalsSea Otters & Polar Bears no special adaptations; similar to terrestrial mammals

    Sirenians have lipid filled zygomatic process (skull bone) connects to ear analogous to pan bone in odontocetes

    Poor directionality and lack of high frequency sound reception reason for high number of boat strikes

  • Pinniped SoundsIn air vocalizations classified by species, age, & sex

    Otariids more vocal than phocids

    Male calls barks, roars, grunts

    Mother-pup calls used specifically for recognizing & locating each other

    Underwater vocalizations typically male songs

  • Pinniped SoundsWeddell sealN. Elephant sealCalifornia sea lion

  • Other Marine Mammal SoundsWalruses males produce a series of knocking sounds

    Sirenians chirp-squeaks; little geographic variation; key in keeping calves with mothers

    Sea otters above water low-frequency sounds; similar to sea lions

    Polar bears females defensive growls; males - chuffs

  • Other Marine Mammal SoundsWalrus

    Manatee

    Sea Otter

    Polar Bear

  • Cetacean SoundsEcholocation projecting short-duration sounds and listening for reflected echoes

    Signature whistles narrow band frequency modulated (FM) sound with harmonic structure; specific to individuals

    Mysticete sounds low-frequency sounds used for long distance communication

    Prey stunning sounds loud blasts of sound called bangs to debilitate prey

  • EcholocationUsed by about 20% of mammals (bats & odontocetes

    Evolved independently in 5 mammalian lineages (bats, shrews, hamsters, lemurs)

    Dolphins may use successive echolocation clicks followed by multiclick processing

  • Echolocation

  • EcholocationBottlenose dolphin

    Rissos dolphin

    Beluga whale

    Sperm whale

  • Signature WhistlesHypothesized that whistle broadcasts identity of the animal & other information (state of arousal, fear, food, etc)

    More social animals whistle more often

    Often different dialects representing regional distributions

  • Vocal ClansKiller whales & Sperm whales

    Pods share calls including calls specific to individuals

    Pods are loosely associated into clans; share clan specific calls as well some but not all calls

  • Vocal Clans

  • Prey Stunning SoundsBlasts of sounds called bangs used to stun or debilitate prey

    First identified in sperm whales jaw claps

    Energetics of sperm whale feeding ecology

    Evidence difficult to collect 240-250 db of sound required for stunning

  • Empirical EvidenceEmpirical studies suggest that sounds not enough to debilitate playback experiments; conducted with live fish but not live dolphins/porpoises

  • Mysticete SoundsHypothesized to have some form of echolocation never substantiated

    Different equipment form/function of sounds production in odontocetes Most well known sound production from humpbacks- male songs

  • Mysticete SoundsBroad system clicks & pulses

    Low frequency whale tones with very long wavelengths

    Humpbacks sing long complex songs

  • Humpback Songs

  • Mysticete SoundsBlue whale

    Humpback whale

    Bowhead whale

  • Sound in the OceanSound pollution thought to be as detrimental to marine mammals as chemical, thermal, physical

    NATO & Navy Sonar war games

    ATOC Acoustic Thermometry of Ocean Climate 260 watt low frequency sounds

  • Sound in the OceanSound pollution thought to be as detrimental to marine mammals as chemical, thermal, physical

    NATO & Navy Sonar war games

    ATOC Acoustic Thermometry of Ocean Climate 260 watt low frequency sounds

  • Sound in the OceanSources of Human-Generated Ocean NoiseTransportation: Aircraft, ships and boats, icebreakers, hovercrafts and vehicles on iceDredging and Construction: Dredging, tunnel boring, other operations.Oil Drilling and Production: Drilling from islands and caissons, bottom-mounted platforms, and vessels; andoffshore oil and gas production.Geophysical Surveys: Air-guns, sleeve exploders, and gas guns.Sonars: Fish finders, depth sounders, and military systems.ExplosionsOcean Research: Seismology, acoustic propagation, acoustic tomography, acoustic thermometry

  • Sound in the OceanOcean Acoustic Tomography (Acoustic Thermometry) - technique used to measure temperatures across large distances in the ocean

    Sounds travel between transmitter and receiver of known distance (typically 100-5000km); time for sound to reach received depends upon temperature of water (and other variables)

  • Sound in the OceanATOC - Acoustic Thermometry of Ocean Climate

    Most infamous regarding marine mammals

    Public outrage and political reaction primarily caused by misinformation

  • Sound in the OceanAMODE (Acoustic Mid-Ocean Dynamics Experiment) & SYNOP (Synoptic Ocean Prediction) most recent versions

  • Workshop: Navy Sonar and Cetaceans:Why Does RIMPAC have us on High Alert?

  • What Is RIMPACRim of the Pacific Exercise since 1971

    World's largest international maritime exercise

    Hosted and administered by the US Navy, US Marine Corps, US Coast Guard & Hawaii National Guard

    Held biennially in June and July in Hawaii

  • ParticipantsAlways: United States, Canada, and Australia,

    Sometimes: United Kingdom, Japan, Republic of Korea, Chile, and Peru

    Observers: France, Singapore, Malaysia, the Philippines, Thailand, Colombia, Mexico, India, Ecuador, Indonesia, China and Russia

  • PurposeEnhance coordination armed forces in Pacific

    Key to military readiness; conflict "hot spotsChina & Taiwan North Korea & South Korea, US, Japan

  • Conduct ship-sinking & torpedo exercises Test new naval vessels and technologyExercises

  • Marine Mammals and Sound

  • Patterns of ConcernGreece, May 1996atypical mass stranding of 12 Cuviers beaked whales associated with acoustic trials by vessels from NATO

    Bahamas, March 200016 whales (14 beaked, 2 minke) stranded over 2 daysUS Navy vessels were using active high intens