Transcript Marine Mammals

Unit #8 Exam
Overall: Average – 82.99%
Highest – 109
1st: 84.33%
4th: 86.75
2 Failures
2 Failures
100028564 (62)
100022745 (50)
100023842 (26)
100028473 (60)
2nd: 80.87%
5th: 82.65%
3 Failures
2 Failures
100023258 (54)
100023446 (46)
100023161 (64)
100029541 (20)
100038241 (52)
7th: 80.92%
3rd: 87.52%
2 Failures
2 Failures
100023579 (30)
100023608 (55)
100034582 (36)
100023260 (60)
Lowest – 20
Most Missed Questions:
• A shark that carries its eggs within its
body prior to the eggs hatching shortly
before birth would be considered
a)
b)
c)
d)
Oviparous
Viviparous
Cannibalistic viviparous
Placental viviparous
Most Missed Questions:
• Scientists have discovered scales of
chondrichthyes that date back to the
____________ period.
a)
b)
c)
d)
Cambrian
Silurian
Ordovician
Quaternary
Most Missed Questions:
• All of the following are true when considering
shark eyes, EXCEPT:
a) Melanin helps shield their eyes from bright light
b) The tapetum lucidum covers over the eyes of
larger sharks when they bite into prey that could
hit and damage their eyes
c) Sharks have eyes that are well developed for
detecting prey during the day and during the night
d) The tapetum lucidum helps to amplify light in lowlight situations so that the shark can hunt
effectively in the dark
Most Missed Questions:
• Chondrichthyes have several potential methods
of respiration. The method of respiration that is
most similar to our own (human) is
a)
b)
c)
d)
Two-pump
Ram ventilation
Lobed-lungs
Spiracles
Most Missed Questions:
• Using Chart #2, which chondrichthyan can be
found in the greatest numbers in contemporary
times (Cenozoic):
a)
b)
c)
d)
Sharks, rays, and skates
Chimeras
Modern bony fishes
Lungfishes
Figure 24.01
Most Missed Questions:
• Using Chart #2, which chondrichthyan can be
found in the greatest numbers in contemporary
times (Cenozoic):
a)
b)
c)
d)
Sharks, rays, and skates
Chimeras
Modern bony fishes
Lungfishes
Most Missed Questions:
• When considering respiration, a stingray uses
spiracles and _____________ to breathe.
a)
b)
c)
d)
Ram ventilation
Two-pump ventilation
Nictitating membrane
Ampullae of lorenzini
Bellwork: 03/23/2012
Collect the following data:
• Chlorine
Salt Water Tanks
Only:
Water Hardness
• DO
- Phosphate
• Turbidity
- Salinity
• Nitrate
- Calcium
• Nitrite
Make sure to clean out any excess food
from your filter and gravel/sand. Scrub off
• Ammonia
the inside of the glass & clean the outside
with Windex once you are finished.
• pH
• Temperature
(Fresh water only)
Bellwork:
1) The Ampullae of Lorenzini detects:
2) A shark’s olfactory senses can reach
up to _________ meters.
3) What is the benefit of a “rete mirabile?”
What type of fish would have this?
Bellwork: 03/20/2012
1) What organisms are considered Pinnipeds?
2) What are two physical differences between
seals & sea lions?
3) Name 4 characteristics that are found in all
mammals:
Bellwork:
1) Test your water for TAN (nitrate, nitrite,
ammonia) & report all values to me.
2) Change 10 to 25% of your water
depending on those values.
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?
• Mammals have a 4
chambered heart.
• Mammals are warmblooded.
• They have hair/fur.
• Have mammary
glands.
• Give birth to live
young.
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
• 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
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.
Sea Otters and Polar Bears
• Sea otters are found only in the
Pacific Ocean, and have the densest
fur of all animals
• Sea otters inhabit nearshore
environments and dive to the sea floor
to forage on mollusks, crustaceans and
echinoderms (sea stars and urchins)
– Must eat ~25-30% of their body weight per
day
Polar Bear
• Polar bears are semi-aquatic mammals
that spend a good deal of their life
drifting on sea ice in the Arctic
• They feed primarily on seals, which they
stalk at breathing holes
• World’s largest land carnivore
• Thick blubber; translucent fur, black
skin!
• Threatened by the loss of Arctic sea ice!
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?
MANTEE ECOLOGY
• Nutritionally poor diet
• Metabolic rate 20-30 % lower than expected
• Primarily plant diet
-some times eat fish captured in nets & tunicates
• Predation low: crocodiles/alligators and
sharks
• Most mortality:
cold
red tides
boat collision
by-catch
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).
• There are more than 90 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.
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.
• The Japanese, and Norwegian fishing
Industries have been illegally whaling under
false pretenses (scientific whaling).
• It is common for Cetaceans to get caught in
fishing nets meant for other species.
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 and
myglobin molecules in their blood
• Allows for efficient capture and transport of
oxygen
Cont.
• Alter blood distribution
– Rate of flow slows down (Undergo bradycardia)
• Heart rate slows by as much as 80 beats per minute
– 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
Taxonomic History
• Hippopotamids are closest living
relatives
– Followed by ruminants
• i.e. cows
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……
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
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
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
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
www.destination360.com
Bellwork – 03/22/2012
1) What is echolocation & which organ
helps focus the sound used in
echolocation?
2) Which marine mammal has the most
dense fur?
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.
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.
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.
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 200 to 500 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