1. Copyright © 2014 Dawn Witherington
Juveniles have more narrow teeth than adults
and tend to specialize in eating
fishes, including
other sharks.
Juvenile Prey
Adult Prey
Adults seem to prefer seals, but also eat other marine
mammals, sea turtles, and the blubber and flesh of
dead whales.
Why Help Sharks?
These apex predators are critical to how marine ecosystems function. For
example, research reveals that coral reefs with higher numbers of top
predators have greater biodiversity and a higher carrying capacity for
important species. When sharks and other apex predators are removed,
lower level predators increase, herbivorous fishes decline, algae
overgrow the reef, and many marine species are lost.
Large dorsal fin
The fin stabilizes the shark and contains
fibers that stiffen with rapid swimming.
Wide caudal keel and pointed snout
The caudal keel supports and strengthens
caudal (tail) fin movement.
Countershading
From above, a dark top blends in with deep water;
from below, a white belly blends in with the sky.
Sharks are magnificent animals that add tremendously to our life
experience. Owing to this charisma, many people pay to see sharks.
Both directly and indirectly, a live shark is worth money.
Threats to Shark Populations
Because most shark species mature late and have few offspring,
their populations depend on adult sharks breeding over a long
life. But mortality is unnaturally high for most shark species.
Widespread commercial fisheries target sharks or accidentally kill
them as bycatch while targeting other species. Sharks are also
caught for sport. Ironically, the more magnificent a shark is, the
more likely it is to be killed intentionally for its jaws and teeth.
Either as intentional catch or as bycatch, millions of sharks are
killed each year. Many species are being fished out faster than
they can reproduce. Despite the mounting evidence of shark
overfishing and depletion, few countries restrict shark fishing.
Even fewer have managed their shark fisheries to be sustainable.
A Very Large Shark
The Hunt
Great white sharks
are ambush predators
that rely on stealth.
Their predatory style is
to lurk surreptitiously
until opportunity
presents, then swim
rapidly, exploding into
their prey. This often
results in dramatic
breaches and grisly
scenes. What may
seem to humans as
ruthlessness, is in fact
an efficient method
for feeding that
reduces the
chances a shark
would miss its agile
prey. Events where
white sharks injure
humans are extremely
rare and are thought
to be cases of
mistaken identity.
Harbor
porpoise
Bluefish
“Only when we all work together can we make a true impact on our oceans for future generations” — Chris Fischer, Founding Chairman & Expedition Leader, OCEARCH
Where Do They Go?
This example of a year-long
track of a 16-ft, 3500 lb
female white shark tagged
off Cape Cod shows a series
of broad looping sojourns
extending 14 thousand miles.
The path extends into coastal
waters as well as into the
open deep sea, past oceanic
landmarks like the eastern
Gulf Stream and Bermuda.
The shark’s story is told by
data from a transmitter that
broadcasts to orbiting
satellites.
May 3, 2013
Dec 22, 2012
Apr 27, 2013
Feb 21, 2013
Mar 10, 2013
May 17, 2013
Feb 04, 2013
Tagged Sep 18, 2012
Shark Tracker
Transmitters attached to the
shark’s dorsal fin send signals to
orbiting satellites whenever the
dorsal fin breaks the water’s
surface. The signals allow
researchers to plot movements in
real time, outlining a descriptive
story of each shark’s travels.
Up close and personal with a top predator
Large,
triangular
dorsal fin
Large dark
eyes, with an
iris ringed in
blue
Dorsal
coloring typically
greyish-brown
Bluntly
pointed
snout
Countershading
(a sharp color
change between
top and bottom)
Wide
caudal keel
Size and Weight: Adults can reach over
20 feet and weigh 5000 pounds.
Age: White sharks live to more than 60 years.
Reproduction: Females mature in 12–14
years and breed only every 2–3 years, giving
live birth to about 5 pups per litter.
FastFacts
Black tips on
ventral
surfaces of
pectoral fins
7 feet (with fins)
Atlantic menhaden
SkatesSquids
Loggerhead
sea turtle
This large marine predator elicits strong
emotions of fear, awe, and curiosity. But as
impressive as they are, great white sharks are
in trouble. New tracking technologies
are beginning to reveal the
mysterious lives of these great
fish, providing information that
is critical to protecting them.
Gray seal
Spiny dogfish shark
P A R T N E R S
www.keepersofthecoast.org