Transcript Marine Mammals

Bellwork: 02/28/2014
1. Change 10 to 25% of your tank water today if
you have not done so this week.
2. Check the water chemistry of your tank and
turn a copy in to me.
3. I am not handing back exams yet, but you can
come see your grade if you talk to me.
4. Answer the following questions & write down
your own opinion. I encourage you to talk to
each other as your are forming your opinions.
Thought Questions: One/Person, Include
name and date on paper
1.
2.
3.
4.
5.
To what extent do humans owe animals ample space without
human interaction and reduction in interference/suffering?
If an animal is in trouble, due to disease, accident, etc, but the
trouble is not caused by humans, should humans intervene to help?
Why/why not?
If an organism is determined to be sentient (able to reason and
recognizes itself as an individual) is it ethical to keep said animal in
captivity for the sake of entertainment?
If the growth of human civilization causes the disruption or
destruction of an animal’s habitat, do humans owe any protections
to the displaced animals?
Should the benefit (not key to survival) of humans always
supersede the survival of a non-human species? Should the basic
needs of humans always supersede the survival of a non-human
species?
Thought Questions:
2. If an animal is in trouble, due to disease,
accident, etc., but the trouble is not caused by
humans, should humans intervene to help?
Why/why not?
Thought Questions:
3. If an organism is determined to be sentient
(able to reason and recognizes itself as an
individual) is it ethical to keep said animal in
captivity for the sake of entertainment?
Thought Questions:
4. If the growth of human civilization causes the
disruption or destruction of an animal’s habitat, do
humans owe any protections to the displaced
animals?
Thought Questions:
5. Should the benefit of humans always
supersede the survival of a non-human species?
Should the basic needs of humans always
supersede the survival of a non-human species?
02/25/2014
1. Any thoughts/questions so far on the
documentary we are watching?
2. Think skeptically & critically
3. Tomorrow we will start with a review quiz and
then do water changes and water chemistry
Marine Mammals
Marine Mammals
• Like the marine reptiles and birds before
them, several different types of land animals
successfully invaded the ocean:
– Seals, sea lions, and the walrus (order
Pinnipedia)
– Sea otter and the polar bear (order
Carnivora)
– Manatees and dugongs (order Sirenia)
– Whales, dolphins, and porpoises (order
Cetacea)
• 120 species altogether
What is a Mammal?
• Land-dwelling ancestors
• Mammals have a 4
chambered heart.
• Mammals are warmblooded.
• They have hair/fur.
• Have mammary glands.
• Give birth to live young.
Major Marine Mammal Groups
Carnivora
Pinnepeds
• Pinnepeds are marine mammals that have
flippers and blubber, that need to breed on
land.
• Seals, Walruses, and Sea Lions all belong to
this Order.
• Pinnepeds live in cold water, they have a
thick layer of blubber to keep them warm.
• They are mostly carnivores and feed on squid
and fish.
• They have streamlined bodies and are
excellent swimmers.
• Seals are the largest group of pinnepeds.
•
•
•
•
•
Seals vs. Sea Lions and Fur
Seals
Seals lack prominent
ear flaps
Seals have smaller
front flippers
Seals have fore
flipper claws
Different hip
structures
Different locomotion
strategies
Seals
• Seals have rear flippers.
• They move forward by pulling
themselves along the ground.
• Seals do not have ear flaps.
• They are hunted for their fur
and are protected by the
Marine Mammal Protection
Act of 1972.
• There are approximately 19
species of Seals.
Weddell seal
New Zealand fur seal
Sea Lions
• Are also called Eared Seals,
because they have external ear
flaps.
• They can move their rear flippers
forward to walk.
• They are graceful and agile
swimmers.
• These are the animals that you
see at Sea World or an Aquarium
doing tricks and they also work
for the US Navy.
• At one time they were hunted for
their fur, but are now protected by
the MMPA of 1972.
Sea lions and fur seals vs.
Seals
Sea lions and fur seals
(Otariidae)
Seals (Phocidae)
Walruses
• Have large protruding
tusks for digging up
mollusks.
• They have stiff
whiskers for feeling
around on the ocean
floor.
• They are the largest
Pinneped, weighing up
to 2700 lbs.
Sea Otters
• They are the smallest Marine Mammal, weighing
60-80 lbs.
• They lack a layer of blubber, and make up for it by
trapping air in their dense fur.
• They were slaughtered to the brink of extinction
for their beautiful fur, but became protected by an
international agreement in 1911.
• They are playful, and intelligent.
• They eat mostly shell fish and spend most of the
day maintaining their fur.
Sea Otter
• Enhydra lutris
– Native to north Pacific
– 394,000 hairs/cm2
– No blubber
– Female 45 lbs; Male
65lbs
– Diet: Sea urchins,
abalone, mussels,
clams, crabs, snails
and about 40 other
marine species.
– Uses tools
– Dives to 330 ft
– Rests in coastal kelp
forests
Sea Otters
Sea otter as a keystone
species
Bellwork: 04/01/2013
1. What are two differences between a seal and a sea lion?
2. List three characteristics that can be found in all mammals:
3. What do walruses eat and how do they detect them?
Polar Bear
Pop size: 22,000 to 27,000
Weight: 550 to 1,700 pounds
Polar Bear
• Ursa maritimus
– United States, Canada,
Russia, Greenland and
on the Arctic islands of
Norway
– Male: 10 feet tall and
weigh over 1400 lbs
– Female: seven feet
and weigh 650 lbs
– wild polar bears live up
to age 25.
– Good swimmers
– Thick blubber
– Thick fur
Polar bears
• Polar bears are the least
adapted to the marine
lifestyle
• Land animals that are
adapted to the cold
• Considered marine mammals because they feed
almost exclusively on marine organisms
• Very good swimmers, but can’t dive below
surface well
• Hunt seals and walruses, occasionally cetaceans
Range:
• Circumpolar in Arctic
• Range depends on sea ice
• normal range
occasional range over pack
occasional range over permanent ice
Polar Bears
• They are semi aquatic, and inhabit both
the land and the sea.
• They feed primarily on seals.
• They have recently been put on the
endangered species list because of loss
of habitat due to global climate change.
Manatees and Dugong
• Sirenians (order Sirenia) include the
manatees and dugong
• Sirenians, also known as sea cows, have
a pair of front flippers, but no rear limbs
• Swim with up-and-down strokes of their
paddle- (manatee) or V- (dugong) shaped
tails
• Closest land relative is the elephant!
West African manatee
Similar to W. Indian manatee but:
blunter snout
more protruding eyes
more slender body
West Indian manatee
Dugong
Tusks
Cetacean-like tail
No nails on flippers
Totally marine
Amazonian
Manatee
<3m long
White patches
Totally freshwater
Manatees
The Florida Manatee
Dugong
Manatees and Dugong
• Sirenians are the only herbivorous marine
mammals; feed on aquatic plants and
algae
• Some species live in fresh and/or brackish
water
• Inhabit temperate or subtropical waters
• Severely threatened by motor boat
collisions, harmful algal blooms, pollution,
and severe winters
10,000
Dugong Range
Manatee
9.8 ft, 800-1200lbs
3,000 in U.S.
Stellar’s Sea Cow
(the sirenian you’ll never see)
• The Stellar Sea Cow was a large,
herbivorous marine mammal formerly
abundant in the North Pacific
• Described by naturalist Wilheim Stellar in
1741; hunted to extinction within 27 years
of discovery!
– 8 meters long
– Fed on kelp
– Did otter hunting
play a role?
Cetaceans
• This is the largest group of Marine Mammals,
consisting of Whales , Dolphins, and
Porpoises.
• These, of all the Marine Mammals, have
made the most complete transition to aquatic
life.
• These animals spend their entire lives in the
water.
• They are streamlined, and look remarkably
fish-like.
• They breathe air through lungs and have
nostrils on the tops of their heads called a
blowhole (some single, some double).
Order Cetacea
• Adaptations for deep diving
• Use oxygen efficiently
– Able to absorb 90% of oxygen inhaled
– Able to store large quantities of oxygen
– Able to reduce oxygen required for
noncritical organs
• Muscles insensitive to buildup of carbon
dioxide
• Collapsible lungs
Mysticeti
• Most of the largest Cetaceans
– i.e. Blue Whales (Balaenoptera musculus) which are the
largest animal in history
• Exceeding 100 feet and weigh as much as 160 tons
– Smallest is the pygmy right whale (Caperea marginata)
• Measure up to 23 feet
– More examples: humpback whale (Megaptera
novaeangliae), fin whale (Balaenoptera physalus), and
southern right whale (Eubalaena australis)
Odontoceti
• Largest and most
diverse group
– i.e. the sperm whale is
the largest
• Reaching about 60 feet
– The largest living
predator of warmblooded animals is the
killer whale
– More examples:
Dolphins and
porpoises
Sperm Whale
Order Cetacea
• Suborder Odontoceti
(toothed)
– Dolphins, porpoises,
killer whale, sperm
whale
– Echolocation to
determine distance
and direction to
objects
– Determine shape, size
of objects
Bottle Nose Dolphin – Tursiops trucatus
Harbor Porpoise
Dolphins vs. Porpoises
• Porpoises
–
–
–
–
Smaller, more stout body shape
Blunt snout
Triangular, smaller dorsal fin
Blunt or flat teeth
• Dolphins
–
–
–
–
Larger, more streamlined shape
Longer rostrum
Falcate dorsal fin (hooked)
Pointy teeth like killer whales (orca)
Taxonomic History
• Hippopotamids are closest living
relatives
– Followed by ruminants
• i.e. cows
– Followed by Artiodactyls
• There are more than 120 species of
Cetaceans.
• They are divided into two groups: toothed
Whales (which includes Dolphins and
Porpoises), and toothless Whales which
have a Baleen.
• Instead of teeth, Baleen Whales have rows of
flexible, fibrous plates, that hang from the
upper jaws (called a Baleen). These are
used to filter out plankton and tiny organisms
from the water.
• Baleen Whales are the largest animals to
ever have lived on this planet.
• There are 13 species of Baleen Whales, the
Blue Whale being the largest at up to 110 ft.
long, and up to 200 tons.
• The remaining 80 species of Cetaceans are
toothed Whales.
• Their teeth are adapted for a diet of squid,
fish, and other prey.
• Teeth are used to catch and hold prey, not to
chew it.
• The largest of the toothed Whales is the
Sperm Whale, made famous by the novel
“Moby Dick”.
• Killer Whales, or Orcas, are predators, eating
seal, penguins, sea otters, and fish.
• They are more common in cold water, but are
found round the world.
Use of Baleen
SLEEP
• Voluntary breathing – must be conscious
to open blow hole.
• A few species sleep as such:
– Right whales (very buoyant)
– Sperm whales (float – do not have to breathe
for hours at a time)
• Duplication of brain function – part of brain
can sleep while another part awake.
How do Cetaceans reduce drag
for fast swimming?
• Fusiform body
– Tapered at both ends
• Paddle-shaped front limbs
• No external digits or claws
• Tail flattened laterally and bearing horizontal
flukes at the tip
• Vestigial ear pinnae
• Hairless body
• Thick subcutaneous blubber layer filled with
fat and oil
• Dolphins are highly intelligent creatures, and can
be easily trained.
• They are very playful, and have been known to
“escort” ships for miles at a time.
• Porpoises have flattened spade-like teeth and
shorter noses than dolphins
• Dolphins, Porpoises, and Whales travel in groups
called Pods.
• They are protected by the MMPA of 1972, but are
still hunted.
Marine Mammal Project
1. Pick your partner if you want one
2. Groups can be no larger than 2
3. Pick a list of animals for your project
4. The order that you get to select your organism
will be random
5. Due April 17th
Coping with Cold Climates
• Small cetaceans
– Have high metabolic rates
– Flippers and flukes have a
countercurrent heat
exchange system
• Heat from arterial blood
warms venous blood as it
returns to the heart
• Large cetaceans
– Small surface to volume
ration
• Lose little heat to the
surrounding environment
• Both are insulated by
thick blubber layer
Physiological Adaptations for
Deep Diving
• Rapid exchange in lungs
– Enhanced by double capillary layer in the
intraalveolar septae
– Humans use 4% of Oxygen inhaled,
Cetacea use 12%
– Twice the number of erythrocytes (red
blood cells) and myglobin molecules in
their blood
• Allows for efficient capture and transport of
oxygen
Physiological Problems with
Deep Diving
• Increased pressure with increased
depth
• At high pressure gases go into solution
more quickly
• Air breathing organisms have a problem
with Nitrogen gas absorption into blood
– Causes decompression sickness
• i.e. Bends or Caisson’s Disease
Physiological Solutions to Deep
Diving
• Structural Adaptations
– Lungs are small
• The total amount you take in
= the total amount you let out
– Dead air spaces are large
• i.e. trachea and nasal cavity
– Trachea is large and
supported by cartilaginous
rings
– Bronchioles are small but
braced by muscles and
cartilaginous rings down to
alveoli
– Ribs are free from sternum
Sperm Whale – Physeteridae
www.nwf.org/nationalwildlife/article.cfm
Cont.
• Mechanism
– Total exhalation before diving
– Diving pressure forces collapse of lungs
• Forces air into dead air spaces, including nasal
passages
– Dead air spaces devoid of vascular tissue
– Nitrogen is six times more soluble in oils then in
water
• Blubber is highly vascular and serves as Nitrogen
reservoir
• Oil also present in nasal sinus and may absorb nitrogen
there as well
Cont.
• Alter blood distribution
– Rate of flow slows down (undergo bradycardia)
– Eliminated at non-critical organs via shunts
• i.e. digestive tract
– Reserved for critical tissues
• i.e. heart and brain
• High tolerance to Carbon Dioxide and lactic
acid build up in tissue
Communication
• One way Cetaceans communicate is through
Echolocation.
• They release tiny bubbles through their
blowholes and make clicking sounds to
communicate with each other and determine
distances, and warn others about danger.
• This is natures version of Sonar.
• The Melon (fatty structure on the top of their
heads) focuses and directs these sound
waves.
• Cetaceans produce a rich variety of sounds
tha are associated with different moods,
sexual signaling, feeding, alarms……
Communication
• Flukes or Flippers
– Slap the surface
• Breaching
– Leaping from the waters
surface
– Helps them to attain an
elevation of several yards
• Spy-hopping
– Raise head out of water to
investigate objects or
potential prey
Echolocation
• Good vision of marine
mammals is limited by
ocean conditions.
• Mammals emit clicks of
different pitches.
– Low frequency – great
distance
– High frequency – closer
range
• Dolphins can detect
schools of fish at more
than 100 meters
(330 feet).
Echolocation
• Toothed whales send sound through water.
• Sound is reflected, returned to the animal,
and interpreted.
• An evolved inner ear structure may help
toothed whales pick up sounds.
• Increased marine noise pollution may affect
cetacean echolocation.
Echolocation
LONGEVITY
• Harbour porpoise – 15 years
• Bottlenose dolphin – 50 years
• Killer whale – 90+ years
• But only 20-25 years in captivity
• Blue whales - 100+ years
• Bowhead whales – 218 years +
Long life cycles and low reproductive
rate means that the recovery of
depleted populations is slow
Mating
• Usually have one mating season per
year
• Gestation is about 10 to 17 months
• Females give birth to a single calf every
one to six years
• Calves are born tail first and must swim
from the moment of birth
• Mysticetes nurse for about six months
• Odontocetes nurse for over two years
Social behavior
• Highly sociable within their respective
species; often forming pods
– Pods often collaborate in hunting, playing,
traveling, and taking care of young
– Usually remain in pods throughout their life
– Pods are beneficial because hunting is
easier in a group; also pods decrease
predation
Breaching
• When Whales leap in the air and loudly
crash on the surface of the water.
• This can be a warning signal, getting rid
of external parasites, fun, or a way of
scanning the surface.
Ecosystem Roles
• Vital roles as consumers
• Host a range of internal
parasites
– Cestodes in their intestines
(Tetrabothrium and
Diplogonoporus)
– Plerocercoids in their blubber
(Phyllobothrium and
Monorygma)
– Trematodes in their stomachs,
livers, intestines, and sinuses
(Bolbosoma)
• Host a range of external
parasites
– Cookie-cutter sharks (Isistius
brasiliensis)
Cont.
• Cetaceans are mutualists with animals that
feed on ectoparasites
• Birds have a commensal relationships with
cetaceans
– Seagulls often follow schools of dolphins and
consume small fish stirred up by the feeding
cetaceans
– Pilotfish (Naucrates ductor) sometimes
accompany killer whales and eat scraps from their
kills
Economical Importance for
Humans
• Disadvantage
– Impact commercial
fisheries due to competition
for fish
• Advantage
– Hunted for meat, oil, and
blubber in 19th century
• Oil is used for lighting and
heating
– Important for entertainment
and tourist industries
Killer Whale
Whaling
• 1600’s Europeans exploited whales in North Atlantic
• Americans dominated whaling industry.
• Hunted for blubber which was used to make soap
and lamp oil
• Baleen used for making stays on corsets.
• Explosive harpoon developed in 1800’s
• Right Whales first to be seriously depleted. Slowswimming, floats after being harpooned.
Explosive Harpoon:
Whaling
• 1900’s Whaling moved to Antarctic feeding grounds.
Reached its peak in 1930’s Estimated that more than
1 million whales killed in Antarctica.
• Blue whales yielded more than 9000 gallons oil.
30,000 blue whales killed during 1930-31 season,
200,000 killed between 1924 and 1971.
• The Japanese, Iceland, Faroe Islands, and Norway
are the main contemporary whaling countries
• Japanese and Norweigian fishing Industries have
been whaling under false pretenses (scientific
whaling).
• It is common for Cetaceans to get caught in fishing
nets meant for other species.
Faroe Islands: grindadráp
• The event, considered more of a party
in modern times, takes place every
summer
• 950 to 1,000 pilot-whales killed during
each hunt
• Even in the Faroe islands, pilot
whales are considered unsafe for
human consumption
Faroe Islands: grindadráp
Faroe Islands: grindadráp
Faroe Islands: grindadráp
Faroe Islands: grindadráp
Whaling (cont.)
• 1946 – International Whaling Commission set up by 20
countries to stop “over-fishing”. Collected data on whale
numbers from whalers, set non-binding, annual quotas.
• After WWII - Demand for whale oil dropped, due to substitutes
created. Whale meat still in demand by pet-food industry and
Japanese kujiraya or whale-meat bars
• 1972 U.S. passed Marine Mammal Protection Act which bans
hunting of all marine mammals(exception are Alaskan native
fisheries) and importation of all marine mammal products.
Whaling (cont.)
• 1974 IWC protected blue, gray, humpback, right whales
• 1985 moratorium declared on all commercial whaling by IWC.
• 1987 Soviet Union halted all whaling/1988 Japan, Iceland and
Norway opted to continue whaling of minke, fin and sei whales
under “scientific whaling”. Iceland dropped out of IWC
• 1994 IWC members created Antarctica as sanctuary, main
feeding ground of 80% of remaining great whales.
Whaling
• International Whaling Commission
(IWC) 1948 – established to manage
whale hunting
• In 1986, 72 IWC nations banned
whaling
• Three ways to legally hunt whales:
– Objection to IWC ban
– Scientific whaling
– Aboriginal subsistence whaling
When the whaling moratorium was
enacted, Norway put in a
reservation.
Norway is, therefore, NOT BOUND
BY THE BAN. It initially respected
the ban, but then restarted
commercial whaling in 1993.
Japan eventually signed up to the
whaling moratorium.
However, it uses a loophole in the
moratorium that allows whales to
be killed for scientific research.
After blubber and stomach content
samples are taken, meat is
processed and sold in markets
In 1994, the International Whaling
Commission made the Southern Ocean
a Whale Sanctuary
– hunting of whales is banned in this area
regardless of the moratorium
Despite this, Japan still hunts minke
whales in the Antarctic for
‘scientific purposes’
SCIENTIFIC PERMITS
... A report distributed at the IWC by
Kaschner & Pauly refuted
the Japanese claims that whales are eating too many fish
"Our analysis clearly shows that there is no evidence that food
competition between [marine mammals and fisheries] is a global
problem."
"Consequently, there is little basis to blame marine mammals for the
crisis world fisheries are facing today."
"We find that the bulk of consumption by marine mammals occurs in
areas of low overlap [with fisheries]…
In other words, what marine mammals consume is largely stuff that
we do not catch in areas where we do not fish.“
"The bulk of what they eat is actually not fish, it’s krill and other
things that we don’t eat."
Dolphins and Man
• Dolphins are being substituted for whales by some
countries. Not protected by IWC
• 28 species are in immediate danger of extinction
• Vaquitas – small, shovel-nosed porpoise of Gulf of
California – only 100 to 300 left.
• Depleting fish and squid on which dolphins feed.
• Peru – dolphin meat cheaper than beef or chicken
• Tuna Fishermen – use purse seine nets and drift
nets which trap and drown many dolphins
Purse Seine and Drift Nets
Drift net
Closing Purse Seine Net
Fishing
Purse seine net
•
Whales as Endangered
Species
Fewer whales now
than before whaling
• International Whaling
Treaty
• Hunting of gray whale
banned in 1938
• Gray removed from
endangered list in
1993 as population
rebounded