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Elasmobranchs
SHARKS AND RAYS
Elasmobranchs
Fish with:
Includes:
•
Cartilaginous skeleton
•
Sharks
•
5 or more gill slits
•
Rays
•
Skates
Fossil Record
•
Earliest sharks – 450 mya
•
200m years before dinosaurs
•
Megalodon
•
•
16 million years ago
•
Extinction 1.6 million years ago
Whorl tooth shark
•
•
270 mya
Earliest rays – 150 mya
Over 470 Species
6 inches to 50 feet
• 50% less than 3 ft.
• 80% less than 5 ft.
Range and Habitats

98% marine

Bull sharks
 1,000
miles up Miss.
 2,300
miles up
the Amazon
Polar to Tropical
Near Shore
Surface to 10,000 Feet
Cookie Cutter Shark
Over 500 Species
Schooling Rays

http://channel.nationalgeographic.com/channel/untamed
-americas/videos/gigantic-school-of-rays/
Sharks
THE TRUTH ABOUT JAWS . . .
Sharks are
unreasonably
feared by people.
It’s estimated that
for every fatal shark
attack up to 10
million sharks are
killed by humans.
1 in 1,378,067 Chance
•
More likely to die from:
• Falling
• Flu
• Lightening
• Fireworks
• Air/space accident
• Dog attack
Mistaken Identity
Who is in danger?
• Scientists estimate that
100 million sharks are
caught and killed each
year.
• Over 11,000 per hour.
Shark Fin Soup
Up to $100 per bowl.
$880 per pound.
Hawaii, Illinois, New York, Maryland, Delaware,
Massachusetts, Oregon, California and Washington have
banned the sale of shark fins.
Finning Revenue
Worth more Alive
$108 = The value of a shark
killed for consumption.
$2 million = The tourism
value each individual reef
shark can contribute to a
coastal community over
its lifetime.
Informed consumer
Know where your seafood comes from and how it is caught.
Avoid shark products including seafood, shark cartilage
supplements, and souvenirs.
Indirect Human Impact
•
Bycatch
•
Entanglement
•
Drift nets
•
Swim areas
Top Predator
Help to maintain a healthy ecosystem by
eating the weakest of their prey.
Without Sharks
Off the mid-Atlantic coast, shark
populations were destroyed.
As a result cow-nose rays, a
former shark prey, grew out of
control.
The rays depleted the scallops,
ending a 100 year old scallop
fishery.
Reproduction
•
Oviparous (egg laying)
•
Viviparous (live birth)
•
Ovoviviparous
Yolk
Embryo
Population Growth
•
Slower to mature
•
•
Long gestation
•
•
6-24 months
Time between breeding
•
•
Some 7+ years
Sometimes years
Relatively few pups
Research &
Conservation
http://www.ocearch.org/
Research &
Conservation
http://www.seattleaquarium.org/sixgill-shark/research
Sharks in Puget Sound
Spiny dogfish
shark
Visiting sharks
that are rarely
seen:
Blue shark
Sevengill shark
Salmon Shark
Sixgill shark
Shortfin mako
Common thresher
White shark
Basking shark
"Never doubt that a small group of
thoughtful, committed people can change
the world. Indeed, it is the only thing that
ever has."
-- Margaret Mead
Learn More
www/pdza.org/savesharks

WA species ID

WA state shark fin law

International shark research
projects (Florida Museum of Natural History)
Share your awareness
with others….