Transcript Sharks - part 2

Most Common Sharks to Attack
• These sharks are larger in size and
consume larger prey
• Great White
• Tiger Shark
• Bull Shark
• Blacktip Shark
How to Reduce Risks of being
Attacked
• Stay in groups, sharks usually attack a animal that is
alone
• Do not go in the water at night, sharks have an
advantage and are more likely to attack
• Do not wear shiny jewelry
• Sharks see color contrast well- avoid bright color
What do Sharks Eat?
• No sharks are true herbivores
• Large irregular feeds
– .5-3% of body weight
• May attack humans, but they are not
designed to feed off humans
– Humans were not around when sharks
developed feeding habits
What do Sharks Eat?
• Specialized
– same thing over and over
– similar habitats offer similar foods
• Common Preys
– squid, fish, turtles, sea lions, and crabs,
What do Sharks Eat?
Facts
• Great Whites usually consumer 11 tons of meat per year
• 10% of all food consumed goes into making new shark
– growth and body maintenance
– Where is the other 90%
• Found in Tiger Sharks
–
–
–
–
drums
coal
cans of paint
coats
horse parts
chickens
dogs
cattle parts
How do Sharks Eat?
• Some Are Filter Feeders
– passes through bristles along the gills
• Use of Teeth
– pliable dentine covered by harder enamel
• Arranged in Rows
– lost teeth/rows replaced by the ones behind
– happens about every two weeks
– can go through 20,000 teeth in a life time
Why Conserve
• Sharks are a natural by catch of many
longline fishing industries fishing for tuna
and billfish. Due to hazards imposed on
the crew these sharks are often killed.
• Historically there was a wide market for
Vitamin A, which is produced in the liver of
sharks. There is still a strong market in
Asian communities for shark fins. (Shark
Fin Soup)
• So why conserve?
– Many societies depend on shark fisheries to
sustain their economies.
– Low reproductive capabilities.
• Gestation period long
• Mature at high age
– Due to over fishing some areas shark
populations have become extremely low.
Conservation Strategies
• Listing at risk species on the endangered
species list.
• Research into shark reproduction.
• Fishing regulations for “keeper” size
sharks.
• Banning/boycotting goods produced from
sharks in countries where it is legal to do
so.
Whale Shark
• Largest fish in the
world
• Very lucrative industry
in India
• Not much is known
about reproductive
capabilities.
• Listed as Endangered
Great White Shark
• Considered the most
deadly shark to
humans
• Often hunted for role
in attacks.
• Little is known about
breeding.
• Listed as vulnerable.
Smalltooth Sawfish
• Once common
throughout the eastern
seaboard
• Almost completely
extinct due to fishing
pressure for their saw.
• Listed as endangered.
• Little is known about this
animal.