Marine Mammals II Flashcards
what kind of hunting grounds do sperm whales have?
- deeper than 1000m for 1 hours
- descend and ascend quick
what do sperm whales hunt?
- spend 20-30 min hunting squid
what is the pressure like at 1000m?
101 atmospheres
what are the risks for air breathers associated with pressure?
- nitrogen narcosis
- embolism
- bends
nitrogen narcosis
nitrogen dissolved in blood affects brain and thinking
- anesthetic effect
- alters consciousness
embolism
bursting of blood vessels in lungs due to blockage by bubbles
- air or gas
- air goes from the lungs to the blood stream
the bends
release of nitrogen gas into tissues and joints
- when pressure increases ( gas goes to liquid form)
- when the pressure decreases then goes from liquid to gas
what is the illness name for the bends?
decompression sickness
what happens to nitrogen with pressure?
- it is compressed into liquid and enters muscles and joints by the bloodstream
what happens with nitrogen when returning to normal pressure?
- comes out as gas bubbles in tissues ans joints
- destroys joints = bends
how much air is exchanged with each breath?
20%
- exhale 16% of O2 taken in and only use 4-5%
- humans get bends from diving deep and surfacing quickly
what are the ways mammals prevent embolism and narcosis?
- compress the lung: store any gas in tough trachea (no exchange) -> elastic lungs (compression/expansion without energy) (lungs are mobile)
- more efficient use of air: few short breaths before diving, inhale same vol as land mammal but EXCHANGE 90% of vol each breath, extract most O2 from air inhaled (16%)
- restrict circulation b/w lungs and rest of circulatory system -> collapse alveoli when diving, close bronchiole valves to alveoli ( limits the movement of N2 gas)
- blood to brain through nitrogen filter (no narcosis)
- store O2 in muscle and blood rather than lungs (no embolism) -> (blood = high hemoglobin, muscle = high in myoglobin), increased vol of arteries and veins and increase blood cell concentration for carrying O2
- decrease HR when diving -> decreases oxygen consumption
what are the adaptations for diving?
- collapse lung
- push air into trachea- less gas exchange
- store oxygen in blood/muscle - prevent embolism
- efficient extraction of O2
what help sperm whales stay buoyant?
spermaceti organ -> becomes solid and heavier on descent and liquid and lighter on ascent
- changes with temperature
what causes dolphins and whales to carry out risky ascent behavior and what is the result?
naval sonar testing-> think it is a predator
- bends: nitrogen bubbles in tissues
what is found in Odontocetes?
- mass stranding - use sonar for hunting
- social groups
- deep diving groups
what are the characteristics of deep diving groups?
- sonar cannot detect sloping shorelines
- groups - altruism is important
-> follows the leader and then there is confusion and can cause issues - potential coupling to earth’s magnetic field -> used for navigation
what is the main sense in marine mammals?
sound
- no smell
- sight is ok
- touch in close encounters
what is used for topography?
low frequency clicks
what is used for communication?
high frequency whistles
what is used for hunting and finding food
high freq clicks
- for sending and receiving sounds
how does echolocation work?
- blowhole - sound generated
- frontal surface of skull - sound reflected off surface
- melon - sound focused
- sound exits
how does sound work in sperm whales?
- sounds come out from trachea
- goes through passage called the “monkey’s muzzle” -> makes sound energy audible
- then goes through spermaceti organ
what is the equivalent to monkey’s muzzle?
phonic lips
where is sound focussed in sperm whales?
sound is reflected off air-filled sac on skull and enters Junk
describe the sound, social behavior and intelligence of cetaceans
- communicate with each other using sound
- large brains relative to body size
- altruism for other species
- trained
what are whale aunties?
females take turns diving for food when there are calves to be protected from killer whales by them
- matriarchal
how do sperm whales communicate?
- over long distances
- clicks like morse code but of same length
- codas personal signature
what is logging?
- whales sleep like a log when not moving
how do M dolphins swim?
side by side
what do calves do while with mother?
sleep while swimming and tow calves in slipstream
- not enough fat to float so need to rely on mother
what do F dolphins do with their brains?
shut down half and switch to the other side
what is a natural fertilizer in oceans?
whale poo
- kicks starts the food chain
what is used to show the productivity in the ocean?
sea birds
how much iron is found in the southern ocean?
12% of iron accounted from whale poop
compare amount of iron in feces and saltwater
10 million times more iron in feces
how do phytoplankton grown and allow for carbon sequestration?
baleen whales eat 1900 million tones of krill/year = 7600 tonnes of feces
what are whales hunted for?
- oil
- meat
- ambergris
- baleen
- whale bone
what is the IWC?
- international whale commission
- founded in 1946
- moratorium on whaling since 1982
- 4 countries still whale for commercial and scientific reasons
- southern ocean whale sanctuary established 1994
- japan building new whaling “mother ship”
what happened post whaling?
- rebound
- moratorium on whaling put in place in 1915
- careful management of subsistence harvest
