In the Jaws of Extinction Shark Awareness and Conservation Slide
2 What is a Shark? Shark is thought to have evolved from a Middle
English Term, shurke (villain) Shark is thought to have evolved
from a Middle English Term, shurke (villain) First sharks lived
about 380 million years ago First sharks lived about 380 million
years ago Considered primitive because they have changed very
little in that time Considered primitive because they have changed
very little in that time Slide 3 Class: Chondrichthyes Class:
Chondrichthyes Sharks, skates, and rays Sharks, skates, and rays
Modern Advances Modern Advances Adaptation as predator Hydrodynamic
body Slide 4 Anatomy of a Shark Slide 5 Slide 6 Circulation Sharks
have a 4 chambered heart like mammals Sharks have a 4 chambered
heart like mammals Faster moving sharks have larger hearts than
slower moving sharks Faster moving sharks have larger hearts than
slower moving sharks Hemoglobin in blood carries oxygen Hemoglobin
in blood carries oxygen Faster moving sharks have more hemoglobin
in the blood than slower sharks Faster moving sharks have more
hemoglobin in the blood than slower sharks Slide 7 Sharks, like all
fish, breathe by extracting dissolved oxygen in the water Sharks,
like all fish, breathe by extracting dissolved oxygen in the water
Water passes into the sharks mouth and is forced over the gills
Water passes into the sharks mouth and is forced over the gills
Most sharks have five gills on each side of the head; some have up
to seven. Most sharks have five gills on each side of the head;
some have up to seven. Respiration Slide 8 Slide 9 Jaws and Teeth
Jaws are only loosely attached to skull Jaws are only loosely
attached to skull Allows for teeth to be used more efficiently
Replaceable teeth attached to skin of jaws, not to the jaw
Replaceable teeth attached to skin of jaws, not to the jaw Can have
up to 7 rows of teeth in waiting Slide 10 Bite range of a Great
White can be in excess of 2.5 feet Slide 11 Diet All are
carnivores, but have highly varied dietary preferences All are
carnivores, but have highly varied dietary preferences Only consume
about 2% of body weight daily Only consume about 2% of body weight
daily Some sharks go weeks without eating Some sharks go weeks
without eating Slide 12 Feeding Habits All are flesh-eaters,
ranging from plankton and small fish to sea lions and whales. All
are flesh-eaters, ranging from plankton and small fish to sea lions
and whales. Do not eat every day Do not eat every day Undigested
food may stay in stomach for several days Undigested food may stay
in stomach for several days Slide 13 Size, Growth and Age Only 50%
of sharks reach a size of less than one meter, and only 5% exceed 4
meters Only 50% of sharks reach a size of less than one meter, and
only 5% exceed 4 meters Size Variation 13 m (Whale Shark) to 20 cm
(spiny pygmy shark) 13 m (Whale Shark) to 20 cm (spiny pygmy shark)
Average life span about 20-25 years but can live to 100 Average
life span about 20-25 years but can live to 100 Most do not
reproduce until late teens Most do not reproduce until late teens
Slide 14 Reproductive Biology Age at sexual maturity 15 to 25 yrs
Age at sexual maturity 15 to 25 yrs All sharks undergo internal
fertilization All sharks undergo internal fertilization Gestation
Periods 9 to 12 months (some 15 months) Gestation Periods 9 to 12
months (some 15 months) Females may retain the sperm until the next
season to fertilize their eggs Females may retain the sperm until
the next season to fertilize their eggs Most have 1 to 2
offspring/yr Most have 1 to 2 offspring/yr Few species can have
120+ offspring/yr Few species can have 120+ offspring/yr Slide 15
Sharks reproduce more like mammals than other fishes 70% bear live
young 70% bear live young 55% babies develop inside female body (by
placenta attachment) 55% babies develop inside female body (by
placenta attachment) Some lay eggs Some lay eggs Sharks egg called
Mermaids s purses Sharks egg called Mermaids s purses Slide 16
Giving Birth Ovipory: 30% lay eggs Ovipory: 30% lay eggs
Ovoviviparous internal incubation of eggs and live birth
Ovoviviparous internal incubation of eggs and live birth
Interuterine cannibalism Viviparous young born fully formed
attached to female and nourished by placenta Viviparous young born
fully formed attached to female and nourished by placenta Slide 17
Viviparous Slide 18 Types of Eggs Slide 19 Shark pup emerging from
egg case Slide 20 The Sharks Skin Skin protected not by scales, but
by hard skin teeth or dermal denticles Skin protected not by
scales, but by hard skin teeth or dermal denticles Feels like sand
paper Important in swimming efficiency Important in swimming
efficiency Denticles point backward to decrease drag Slide 21 Slide
22 Nose to Tail Sharks designed for constant, effortless swimming,
though not as sustained high speeds Sharks designed for constant,
effortless swimming, though not as sustained high speeds Color
blends in with colors of the ocean Color blends in with colors of
the ocean Their senses, like their teeth, are razor- sharp, and
they are quick to investigate anything that could be food Their
senses, like their teeth, are razor- sharp, and they are quick to
investigate anything that could be food Slide 23 Tails and Fins
Propels itself through water with powerful tail fin moving side to
side Propels itself through water with powerful tail fin moving
side to side Fins are non-retractable, used for balance and to
prevent roll-overs Fins are non-retractable, used for balance and
to prevent roll-overs Control direction of shark and act as a
braking mechanism Control direction of shark and act as a braking
mechanism Slide 24 Fin Facts Pelvic and Pectoral fins act like
wings of an aircraft for steering Pelvic and Pectoral fins act like
wings of an aircraft for steering Shark fins are cut off and dried
to make Shark Fin Soup Shark fins are cut off and dried to make
Shark Fin Soup Fins cut and live carcass thrown back into ocean
sharks die slowly by drowning Fins cut and live carcass thrown back
into ocean sharks die slowly by drowning Shark finning is illegal
in the U.S. Shark finning is illegal in the U.S. Slide 25 Shark
Finning in Asia Slide 26 Slide 27 Slide 28 Senses: Swimming
Computers Sharks can see, smell and hear in addition to sensing
movement and electrical fields made by other animals Sharks can
see, smell and hear in addition to sensing movement and electrical
fields made by other animals Uses sense of touch to locate food and
enemies Uses sense of touch to locate food and enemies Sharpness of
senses varies from one species to another depending on lifestyle
Sharpness of senses varies from one species to another depending on
lifestyle Slide 29 Vision Sharks have excellent vision: especially
sensitive to contrast Sharks have excellent vision: especially
sensitive to contrast Sharks probably see color Sharks probably see
color Black cones on back of retina (Tametum lucidum) increases
vision at night and in murky waters. Black cones on back of retina
(Tametum lucidum) increases vision at night and in murky waters.
Can see better at night than cats Slide 30 Slide 31 Scent Detectors
Shark has nostrils located in front of eyes on each side of snout
Shark has nostrils located in front of eyes on each side of snout
Olfactory sacs in nostrils detect scent Olfactory sacs in nostrils
detect scent Blacktip sharks detect one part of scent in 10 billion
parts of water Blacktip sharks detect one part of scent in 10
billion parts of water Most sharks can detect a scent from over a
mile away Most sharks can detect a scent from over a mile away
Slide 32 Detecting Sound Sharks have ears located on top of head
Sharks have ears located on top of head Detect movement of water
molecules Detect movement of water molecules Have detected sound 4+
kilometers away Have detected sound 4+ kilometers away Can detect
heartbeat up to 1 mile Can detect heartbeat up to 1 mile Slide 33
Slide 34 Electro-Sensitivity Sharks are most electrically-sensitive
vertebrate ever studied Sharks are most electrically-sensitive
vertebrate ever studied Use magnetic field of earth as natural
compass for migration Use magnetic field of earth as natural
compass for migration All organisms emit electrical signals varying
in strength depending on animal All organisms emit electrical
signals varying in strength depending on animal Slide 35 Ampullae
of Lorenzini Delicate, jelly-filled canals connected to pores in
the sharks skin Delicate, jelly-filled canals connected to pores in
the sharks skin Visible on the underside of sharks snout Visible on
the underside of sharks snout Can detect incredibly low voltage Can
detect incredibly low voltage Can feel heartbeat up to 1 mile away
Detects electrical stimuli from animals buried in sand or hiding in
corals Detects electrical stimuli from animals buried in sand or
hiding in corals Slide 36 Slide 37 Slide 38 Slide 39 Lateral Line
Specialized, pressure sensitive, hair receptor cells found in
grooves or canals along a central line that runs down each side of
a sharks body Specialized, pressure sensitive, hair receptor cells
found in grooves or canals along a central line that runs down each
side of a sharks body Movement of hairs signal the change in water
pressure caused by other fish Movement of hairs signal the change
in water pressure caused by other fish gauge distance useful in
murky waters or complete darkness Slide 40 Slide 41 Sensing Prey
Usually pick up smell of a victim first Usually pick up smell of a
victim first Tracks down bleeding prey easy meal Tracks down
bleeding prey easy meal Lateral line confirms position of target
Lateral line confirms position of target Ampullae of Lorenzini
picks up electrical activity of prey Ampullae of Lorenzini picks up
electrical activity of prey Closer in, ears pick up sounds Closer
in, ears pick up sounds Within striking distance, shark sees prey
Within striking distance, shark sees prey Sharks brain shuts down
senses Sharks brain shuts down senses Tastes victim by biting, then
swims away Tastes victim by biting, then swims away Victim moving
less, moves in for the kill Victim moving less, moves in for the
kill Slide 42 Behavioral Patterns Swimming usually casual Swimming
usually casual Rarely makes any sudden moves Rarely makes any
sudden moves Noises made by humans usually scares a shark Noises
made by humans usually scares a shark Curiosity often draws sharks
toward scuba divers Curiosity often draws sharks toward scuba
divers Slide 43 Hunting Movements of a shark become erratic during
hunting Movements of a shark become erratic during hunting Blue
sharks are fearless, attacking prey much bigger than themselves
Blue sharks are fearless, attacking prey much bigger than
themselves Great whites often patrol beaches that are known homes
to seals or sea lions Great whites often patrol beaches that are
known homes to seals or sea lions Slide 44 Territorial? Most sharks
are not territorial, simply swim around the oceans Most sharks are
not territorial, simply swim around the oceans Reef sharks form a
base and patrol it Reef sharks form a base and patrol it Grey reef
sharks may consider other sharks and people as a threat Grey reef
sharks may consider other sharks and people as a threat Breeding
sharks become very aggressive Breeding sharks become very
aggressive Slide 45 The Attack Sharks usually circle their prey
before attacking it Sharks usually circle their prey before
attacking it Slowly narrow the circle getting closer and closer
Slowly narrow the circle getting closer and closer Nicitating
membrane covers and protects eyes during the attack rendering the
shark blind during the attack Nicitating membrane covers and
protects eyes during the attack rendering the shark blind during
the attack Some often bump or nudge prey to see if it is soft Some
often bump or nudge prey to see if it is soft Great Whites attack
from below and behind, away from the head Great Whites attack from
below and behind, away from the head Slide 46 Slide 47 Slide 48
Behavioral Considerations Very predictable, very smart and very
social Very predictable, very smart and very social Many who work
with sharks maintain that they have very distinct personalities
Many who work with sharks maintain that they have very distinct
personalities Some sharks display a complex and subtle body
language which may be an attempt to communicate the violation of
their space Some sharks display a complex and subtle body language
which may be an attempt to communicate the violation of their space
Slide 49 Threat Warning Posturing has been displayed by many sharks
as a warning for attack Posturing has been displayed by many sharks
as a warning for attack 1. Swims back and forth in one place 1.
Swims back and forth in one place 2. May drop pectoral fins, raise
nose and hunch back 2. May drop pectoral fins, raise nose and hunch
back 3. Turn toward you and then away 3. Turn toward you and then
away Repeats this process as a warning Slide 50 Slide 51 Slide 52
Avoiding Attack Remaining in the area when a shark displays
posturing behaviors could illicit an attack. Leave the area as
quietly as possible. Remaining in the area when a shark displays
posturing behaviors could illicit an attack. Leave the area as
quietly as possible. Do NOT turn your back to the shark. Do NOT
turn your back to the shark. Dont panic and race for the surface
unless you want to become dinner. They will chase you and they will
win!! Dont panic and race for the surface unless you want to become
dinner. They will chase you and they will win!! Slide 53 Avoiding
Attack Keep an eye on the shark at all times. Keep an eye on the
shark at all times. Be aware of your surroundings, remember sharks
are social animals there may be more! Be aware of your
surroundings, remember sharks are social animals there may be more!
Swim slowly. Quick movements attract attention. Swim slowly. Quick
movements attract attention. Remain close to the bottom until
directly below the exit point. Remain close to the bottom until
directly below the exit point. Slide 54 Slide 55 Quote to Remember
Between the months of five through nine (May to September), go
swimming in the ocean from nine to five Between the months of five
through nine (May to September), go swimming in the ocean from nine
to five Robert Hueter, Mote Marine Laboratory Sharks feed usually
at sunrise and sunset Sharks feed usually at sunrise and sunset If
food is present, they will eat at any time! Slide 56 Slide 57 Slide
58 Swimming Attacks Always stay in groups Always stay in groups Do
not enter the water if you are bleeding Do not enter the water if
you are bleeding Avoid shiny jewelry reflects light and resembles
sheen of fish scales Avoid shiny jewelry reflects light and
resembles sheen of fish scales Avoid contrasting colors yum-yum
yellow Avoid contrasting colors yum-yum yellow Refrain from
excessive splashing fish in distress signal Refrain from excessive
splashing fish in distress signal Sightings of dolphins do not mean
no sharks both eat same food Sightings of dolphins do not mean no
sharks both eat same food Avoid areas where people are fishing
Avoid areas where people are fishing Slide 59 Slide 60 The Sharks
Domain Sharks inhabit every area of the ocean from continental
shelves to the abyssal plains Sharks inhabit every area of the
ocean from continental shelves to the abyssal plains Majority live
in the well-lit surface waters, but a few are found only in very
deep waters Majority live in the well-lit surface waters, but a few
are found only in very deep waters Slide 61 Shark Diversity There
are 8 orders and about 380 known species of sharks inhabiting every
ocean and virtually every marine habitat in the world. There are 8
orders and about 380 known species of sharks inhabiting every ocean
and virtually every marine habitat in the world. New species
emerge, but most known species have changed very little over the
last 300+ million years New species emerge, but most known species
have changed very little over the last 300+ million years Slide 62
Slide 63 Naming Sharks Sharks exhibit certain characteristics that
are sometimes responsible for their naming including Sharks exhibit
certain characteristics that are sometimes responsible for their
naming including Color (leopard sharks, zebra sharks) Special
shapes (Hammerheads, angel sharks) Appendages (Horn sharks) Where
they live (Carpet Sharks) Slide 64 Weird and Wonderful Names
Megamouth sharks have an enormous mouth and over 100 rows of teeth
Megamouth sharks have an enormous mouth and over 100 rows of teeth
Great Whites are known as White Death Great Whites are known as
White Death Blind sharks close their eyes when they are taken out
of the water Blind sharks close their eyes when they are taken out
of the water Fishermen thought the Dogfish shark had teeth like a
dog Fishermen thought the Dogfish shark had teeth like a dog Angel
sharks have large pectoral fins that resemble an angels wings Angel
sharks have large pectoral fins that resemble an angels wings Slide
65 Six-Gilled Sharks: Living Fossils Included Cow Shark and Frill
Sharks Included Cow Shark and Frill Sharks Have six or seven gill
slits Have six or seven gill slits Most similar to primitive sharks
Most similar to primitive sharks Slide 66 Saw Sharks Saw-like
structure on nose Saw-like structure on nose Used for stirring up
bottom in search of small fish and crabs Used for stirring up
bottom in search of small fish and crabs Covered with skin at birth
reduce injury to mom Covered with skin at birth reduce injury to
mom Slide 67 Dogfish Small in size Small in size Important source
of food and are fished all over the globe Important source of food
and are fished all over the globe Slide 68 Horn Sharks Named for
horn-like spines located on their backs next to each dorsal fin
Named for horn-like spines located on their backs next to each
dorsal fin Slide 69 Carpet Sharks Live on the seabed and are
sluggish swimmers Live on the seabed and are sluggish swimmers Not
generally aggressive Not generally aggressive Nurse Sharks, Leopard
Sharks, Wobbegongs, zebra sharks Nurse Sharks, Leopard Sharks,
Wobbegongs, zebra sharks Slide 70 Slide 71 Angel Sharks Live in
shallow, warm seas Live in shallow, warm seas Large pectoral fins
look like angel wings Large pectoral fins look like angel wings
Disguise themselves by covering their bodies in sand Disguise
themselves by covering their bodies in sand Often sold as a
substitute for lobster Often sold as a substitute for lobster Slide
72 Mackerel Sharks Very aggressive nature full of curiosity Very
aggressive nature full of curiosity Include: Great white, mako,
megamouth, sand tiger and goblin sharks Include: Great white, mako,
megamouth, sand tiger and goblin sharks Mackeral sharks named for
eating Mackeral and Herring Mackeral sharks named for eating
Mackeral and Herring Slide 73 Mackerel Sharks Mako, Sand Tiger,
Goblin and Porbeagle Sharks Slide 74 Hammers and Threshers Easy to
recognize Easy to recognize Hammerheads swing heads from side to
side to detect stingrays Hammerheads swing heads from side to side
to detect stingrays Thresher long tail used to frighten and stun
small fish Thresher long tail used to frighten and stun small fish
Slide 75 Requiem Sharks Second most dangerous shark to swimmers and
divers Second most dangerous shark to swimmers and divers Some live
in open ocean while others are found close to the shore Some live
in open ocean while others are found close to the shore Slide 76
Requiem Sharks Silky Sharks, Silvertip Reef Sharks, Blue sharks and
Tiger Sharks Slide 77 Plankton Eaters Harmless, docile sharks
feeding mainly on plankton Harmless, docile sharks feeding mainly
on plankton May grow to lengths of 60 feet and 44 tons May grow to
lengths of 60 feet and 44 tons Whale sharks, Megamouth sharks and
Basking sharks Whale sharks, Megamouth sharks and Basking sharks
Slide 78 MEGAMOUTH SHARKS Megamouth shark was not discovered until
1976 by US Navy Megamouth shark was not discovered until 1976 by US
Navy Deep water dwellers, plankton feeders, poor swimmers Deep
water dwellers, plankton feeders, poor swimmers Slide 79 Gentle
Giants Whale Sharks inhabit all warm, tropical seas Whale Sharks
inhabit all warm, tropical seas Thought to be highly migratory
Thought to be highly migratory About 300 rows of small teeth About
300 rows of small teeth Live bearer of young, with up to 300 pups
at one time Live bearer of young, with up to 300 pups at one time
Slide 80 Strange Sharks Cookiecutter shark 20 in long gouge round
plugs of flesh from victims Cookiecutter shark 20 in long gouge
round plugs of flesh from victims Dwarf sharks 6 in long lives in
deep Pacific Ocean Dwarf sharks 6 in long lives in deep Pacific
Ocean Slide 81 Sharks in the Atlantic Ocean and Gulf of Mexico In
2000 there were 34 shark attacks along the Florida coast In 2000
there were 34 shark attacks along the Florida coast Tiger or bull
sharks said to be responsible Of the 350 shark species, about 80%
are unable to hurt people or rarely encounter people Of the 350
shark species, about 80% are unable to hurt people or rarely
encounter people Slide 82 Sandbar Shark Also called a brown shark
Also called a brown shark Large triangular shaped dorsal fin Large
triangular shaped dorsal fin Can grow to 8 ft Can grow to 8 ft
Slide 83 Sharpnose Shark Distinguished by white spots, long
flattened snout and a thin body Distinguished by white spots, long
flattened snout and a thin body Grows to 3 feet Grows to 3 feet
Slide 84 Blacktip Shark Black tips on dorsal and pectoral fins
Black tips on dorsal and pectoral fins Grows to about 6.5 feet
Grows to about 6.5 feet Number one species for attacks along the
Gulf coast Number one species for attacks along the Gulf coast
Slide 85 Spinner Slender, fast- swimming shark that often leaps
spinning out of the water Slender, fast- swimming shark that often
leaps spinning out of the water Grows to 9 feet Grows to 9 feet
Slide 86 Blacknose Shark Small shark with noticeable dusky smudge
or moustache on tip of its snout. Small shark with noticeable dusky
smudge or moustache on tip of its snout. Maximum length about 4.5
feet Maximum length about 4.5 feet Slide 87 Bull Shark One of the
most dangerous sharks along S.E. coast One of the most dangerous
sharks along S.E. coast Short, broad snout and small eyes Short,
broad snout and small eyes Grows to 11.5 ft Grows to 11.5 ft
Tolerates fresh water Tolerates fresh water Slide 88 Tiger Shark As
dangerous as Bull sharks more likely to attack people As dangerous
as Bull sharks more likely to attack people Broad snout with
telltale stripes on body (spots as a juvenile) Broad snout with
telltale stripes on body (spots as a juvenile) Max length is 18 ft.
Max length is 18 ft. Slide 89 Why are Sharks Important? Maintaining
a healthy ecosystem Maintaining a healthy ecosystem Culling weak
and wounded animals Dont compete with fishermen (take what a fisher
wouldnt catch or would discard) Dont compete with fishermen (take
what a fisher wouldnt catch or would discard) Eliminating sharks
would have catastrophic effect on ocean ecosystem Eliminating
sharks would have catastrophic effect on ocean ecosystem Slide 90
Human Benefit? Squalimine is a broad-based antibiotic produced from
cells throughout body of a spiny dogfish Squalimine is a
broad-based antibiotic produced from cells throughout body of a
spiny dogfish Successfully used against bacterial and fungal
infections and may be key to treating resistant infections Many
sharks harvested for Vitamin A found in their livers Many sharks
harvested for Vitamin A found in their livers Slide 91 Cancer
Preventative? Cancer is very rare in sharks Cancer is very rare in
sharks Once thought to be something in cartilage that prevented
cancer was found to be not true Once thought to be something in
cartilage that prevented cancer was found to be not true People
still seek cartilage pills in heath stores People still seek
cartilage pills in heath stores Costa Rica alone kills over 2.8
million sharks per year to make Costa Rica alone kills over 2.8
million sharks per year to make cartilage pills cartilage pills
Slide 92 The Future? Humans kill up to 100 million sharks every
year Humans kill up to 100 million sharks every year As slow
breeders, sharks cannot replace such losses As slow breeders,
sharks cannot replace such losses Many species of sharks already
endangered Many species of sharks already endangered Fishermen
catch and release sharks, but most die shortly afterward Fishermen
catch and release sharks, but most die shortly afterward Slide 93
Tourism could be key to sharks long term survival Shark photography
Shark photography Shark watching tourism feeding frenzies Shark
watching tourism feeding frenzies Shark wrestling Shark wrestling
Shark dives from reef sharks to great whites Shark dives from reef
sharks to great whites Marine Aquariums only small sharks; large
sharks difficult to keep in captivity Marine Aquariums only small
sharks; large sharks difficult to keep in captivity Slide 94 Slide
95 Protection Marine reserves and breeding ground reserves may be
needed in near future Marine reserves and breeding ground reserves
may be needed in near future Great White are already protected in
California, Australia and S. Africa Great White are already
protected in California, Australia and S. Africa Fishing quotas
Fishing quotas Slide 96 Sharks are amazing animals but difficult to
study, so little is known about them. The more we know and
understand, the more we can learn to respect such misunderstood
creatures
