SEA TURTLES

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SEA TURTLES
"For in the end we will conserve only what we
love. We will love only what we understand. We
will understand only what we are taught."
-B. Dioum
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Sea Turtles

• Sea Turtles have long fascinated humans, and have
  figured prominently in the mythology and folklore
  of many cultures
• Millions of sea turtles once roamed the oceans,
  but now only a fraction remain
• Their spiritual significance has not saved them
  from exploitation for food and profit

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Sea Turtles

• Trade in sea turtle meat, eggs, shells, oil, and
  leather has driven almost every species of sea
  turtles to the brink of extinction
• Also, thousands of sea turtles die each year in
  shrimp nets, gill nets, long-line hooks, and
  polluted waters
• Dramatic changes to coastlines and beach property
  also affect sustainability

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Sea TurtlesCommon Characteristics

• Large, air-breathing reptiles
• Inhabit tropical subtropical seas throughout
  the world
• Shells consist of an upper part, called a
  carapace, and a lower section, called a plastron
• Hard scales (scutes) cover all but the
  leatherback the number arrangement can be used
  to identify the species

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Sea TurtlesCommon Characteristics

• Dont have teeth, but jaws have modified beaks
  suited to their particular diet
• Dont have visible ears, eardrums covered by
  skin
• Hear best at low frequencies
• Sense of smell is excellent
• Vision underwater is good, above water they are
  nearsighted

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Green Sea Turtle
Size 3.5 feet in carapace length 350-400
lbs. Range Tropical Sub- tropical
waters Diet seaweed, algae the only sea turtle
that is a strict herbivore as an adult, Jaws
finely serrated, helps tear vegetation when
eating
Most Well Known
Named for green color of fat under its shell
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Green Sea Turtle (cont.)
Prized meat for food, Flipper skin for leather,
Green fat main ingredient for Turtle soup,
also Eggs dug for food 1 nesting site left
inCaribbean, protected by Archie Carr
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Green Sea Turtle (cont.)

• Habitat Mainly stays near coastline, and around
  islands and lives in bays and protected shores
  rarely seen in open ocean. Problem with staying
  in shallow water??
• Population Estimate 203,000 nesting females
  today 88,520 nesting females

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• Female green sea turtle leaving the nesting beach

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Green Sea Turtle Reproduction

• Nest every 2-3 years
• Each female nests 3-5x per season
• 12 days between nestings
• 115 eggs per nest
• Eggs incubate for 60 days

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Green Sea Turtle nesting and distribution
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Loggerhead Sea Turtle
Size 4 ft long, 350-400 lb Range tropical
sub tropical Waters throughout most
of world Diet mollusks, crustaceans,
fish, Jellyfish Main nesting beaches
Caribbean, Central America, Yucatan
Population estimate 60,000 nesting females
today 44,560 nesting females
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Loggerhead Reproduction

• Nest at intervals of 2, 3, or more years.
• Nests between 4 to 7 times per season.
• Lays average of between 100 to 126
  eggs in each nest.
• Eggs incubate for about 60 days.

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Loggerhead nesting and distribution
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Leatherback Sea Turtle

• Named because its shell is made of a layer of
  thin, tough, rubbery skin that looks like leather
• Carapace does not have scales, except in
  hatchlings

Focus of Dr. Paladinos research
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Leatherback Sea Turtle (cont.)
Size 6 ft long, 12 ft Flipper span, 1000
lbs Range Pacific, Indian, Atlantic
Oceans, 60 N to 60 S Diet Mostly
jellyfish Population Estimate
35,000 nesting females today 35,860
nesting females
Largest
Greatest Range
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Leatherback Sea Turtles

• Other details mainly nest in Northern
  SouthAmerica

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Leatherback Nesting

• Females nest in intervals of 2-3 years
• 10 days between nestings
• Nests 6-9x per season
• Lays 80 fertilized 30 unfertilized eggs
• Eggs incubate 65 days

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Leatherback Nesting sites
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Hawksbill Sea Turtle
Size 3 feet in carapace length 150-250
lbs Range tropics only, around reefs,
worldwide Diet sponges anemones Shape of
head/beak allow it to get food from crevices in
coral reefs Pop 8,000 (in 2002) nesting
females today 22,900
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Hawksbill Sea Turtle (cont.)

• Special Characteristics tortoise-shell,
  hunted for jewelry and wall hangings
• Carapace would yield 50-100 per pound
• Up until mid 90s, Japan importing 20 tons of
  shells per year

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Hawksbill Sea Turtle

• Females nest every 2-3 years
• 2-4x per season every 15 days
• Each female lays 160 eggs
• Eggs incubate 60 days

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Hawksbill Nesting Sites
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Kemps Ridley Sea Turtle

• Atlantic Ridley
• Size less than 100 lbs 2 feet long
• Range adults limited to Gulf of Mexico-- nests
  only on small stretch of beach, Rancho Nuevo
  Mexico juveniles range between tropical and
  subtropical coastal areas of NW Atlantic Ocean
  and can be found down East coast US

Most Endangered
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Kemps Ridley Sea Turtle

• Females nest every year
• Females nest 2x per year
• 110 eggs per nesting
• Eggs incubate 55 days

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Kemps Ridley Sea Turtle

• Their diet consists mainly of swimming crabs, but
  may also include fish, jellyfish, and an array of
  mollusks.
• Number of Nesting females
  1942 42,000
  1995 1,429
  today 2,500

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Kemps Ridley Nesting Sites
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Olive Ridley Sea Turtle

• Size 2 feet long, less than 100 lbs
• Range tropical regions of the Pacific, Indian,
  and in Atlantic off of South America
• Diet crabs, clams, mussels (powerful jaw)

Greatest Population
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Olive Ridley Sea Turtle

• Nests in arribadas (mass nestings)
• Females nest 2x per season
• Female lays 105 eggs per nest
• Eggs incubate 55 days
• Number of Nesting
  Females 500,000
  today 800,000

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Olive Ridley Nesting Sites
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Flatback Sea Turtle

• Named because its shell is very flat, but still
  somewhat rounded
• Size 3 feet long, 200 lbs
• Diet sea cucumbers, prawns, and invertebrates

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Flatback Sea Turtle (cont.)

• Range Most restricted limited coastal waters
  of Northern regions of Australia and the Gulf of
  Papua, New Guinea
• Population 7,500 nesting females today
  20,285

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Australian Flatback Sea Turtle

• Females nest 4x per season
• Each nest has 50 large eggs
• The eggs incubate for about 55 days.
• When hatchlings emerge, they are larger than most
  species

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Flatback Nesting Sites
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Black Sea Turtle

• Size 150 lbs
• Range Eastern Pacific,
• 30 N to 30 S
• Diet seagrasses, algae,
• invertebrates as juveniles
• Other details nesting in Central
• South America Galapagos Islands
• Possible subspecies of Green Sea Turtle

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Black Sea Turtle

• Although this turtle enjoys a protected status in
  the Galapagos Islands, some portions of this
  population are nesting in coastal Ecuador where
  they are being exploited.
• In Mexico, despite laws to protect them, the
  turtles continue to be captured and sold

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Carapace Patterns
Green Turtle
Hawksbill
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Carapace Patterns (cont.)
Kemps Ridley
Loggerhead
Leatherback
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Nesting Behavior

• Most commonly nest at night
• Return to natal beach (females return to the
  beach on which they were born to lay their eggs)

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Nesting (cont.)

• Females lumber up onto beach at night
• Dig a hole, lay the eggs, cover the hole, and
  return to the ocean, all in about one hour
• Average 100 eggs laid in each nest
• Average depth of nest is 2 feet

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Nest

• -Sand permits gas exchange
• -Hatchling gender controlled by incubation
  temperature
• 30.2 C gives 50/50 balance
• If cooler, more males
• If warmer, more females

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Sargasso Sea
Hatchlings of Kemps Ridley swim far out into the
major ocean Currents and spend the first 4-5
years of their lives drifting Around on patches
of sargassum
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Studying Migration
Important to conservation efforts Use Satellite
devices to track turtles, Able to map migration
patterns
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Threats to Sea Turtles
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Threats to Sea Turtles

• HUMANS are the biggest threat
• Sea turtles are hunted/harvested for their fat,
  eggs, shells for food and decorations
• Also killed accidentally by commercial fishing
  industry
• Population greatly affected by availability of
  nesting grounds

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Coastal Armoring

• Reduces available nesting sites

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Artificial Lighting

• Nesting females inhibited by lights
• Hatchlings confused, may not reach ocean

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Pollution Trash

• Plastic bags choke drown sea turtles that
  mistake the bags for jellyfish, mostly affects
  _?__
• Pollution--tumors

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T.E.D.s

• Turtle Excluding Device
• On shrimp nets
• Prevents turtle entry
• Successful
• Now, used 97 of the time
• US Shrimp Fleet- 15,000 boats, 40,000 part time
  trawlers

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General Information on Sea Turtles

• Adaptations-
• Shells-
• Egg laying-
• Hatchlings-
• Hatchlings swimming frenzy-

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General Information on Sea Turtles

• Turtle tears-
• Tortuga (as in the Dry Tortugas)-
• Archie Carr-
• Removing nesting females bad animal husbandry-
• National Marine Fishery Service in water
• US Fish Wildlife Service out of water

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Kemps Ridley Turtle Nesting on Padre Island,
Texas

• 75 92 2000 eggs per year transported, 16,000
  released
• Nests on Padre Island in 95 4
• Nests on Padre Island in 96 6
• Nests on Padre Island in 97 9
• Nests on Padre Island in 98 13
• Nests on Padre Island in 99 16
• Nests on Padre Island in 00 12 (first returner
  from previous year)
• Nests on Padre Island in 01 8
• Nests on Padre Island in 02 40
• Nests on Padre Island in 09 117 (Total in
  Texas 197)

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Turtle Conservation Efforts

• http//texashighways.com/slideshow/seaturtle/
• http//www.mcsuk.org/marineworld/turtles/turtlesi
  ntrouble
• http//www.mcsuk.org/media/turtle_flashvideo/index
  .html