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Hawksbill Sea Turtle

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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
              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
               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
               Sea Turtles
         Common 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
                Sea Turtles
         Common Characteristics
   Don’t have teeth, but jaws have modified
    “beaks” suited to their particular diet
   Don’t 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
               Green Sea Turtle
                               Size: 3.5 feet in carapace
                               length; 350-400 lbs.

                               Range: Tropical & Sub-
                               tropical waters

                               Diet: seaweed, algae; the
*Most Well Known               only sea turtle that is a
                               strict herbivore as an adult,
Named for green color of fat   Jaws finely serrated, helps
under its shell                tear vegetation when eating
         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 in
Caribbean, protected by
Archie Carr
    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
   Female green sea turtle leaving the nesting
    beach
    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
Green Sea Turtle nesting and
        distribution
            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
    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.
Loggerhead nesting and
      distribution
           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. Paladino‟s research
    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
     Leatherback Sea Turtles
Other details: mainly
  nest in Northern South
  America
       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
Leatherback Nesting sites
             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
    Hawksbill Sea Turtle (cont.)

 Special
  Characteristics:
  “tortoise-shell,”
  hunted for jewelry
  and wall hangings
 Carapace would
  yield $50-100 per
  pound
 Up until mid 90’s,
  Japan importing 20
  tons of shells per
  year
       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
Hawksbill Nesting Sites
      Kemp’s 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           *Most Endangered
  Atlantic Ocean and can be
  found down East coast US
    Kemp’s Ridley Sea Turtle
 Females nest every year
 Females nest 2x per year
 110 eggs per nesting
 Eggs incubate 55 days
     Kemp’s 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
Kemp’s Ridley Nesting Sites
      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         *Greatest Population
  jaw)
      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
Olive Ridley Nesting Sites
        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
    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
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
Flatback Nesting Sites
           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
          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
         Carapace Patterns




Green Turtle   Hawksbill
    Carapace Patterns (cont.)




Kemp’s Ridley                 Loggerhead
                Leatherback
         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)
                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
                    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
                   Sargasso Sea




Hatchlings of Kemp‟s 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
             Studying Migration




Important to conservation efforts
Use Satellite devices to track turtles,
Able to map migration patterns
Threats to Sea Turtles
      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
            Coastal Armoring
   Reduces
    available
    nesting sites
Artificial Lighting
                Nesting
                 females
                 inhibited by
                 lights
                Hatchlings
                 confused,
                 may not
                 reach ocean
              Pollution & Trash




 Plastic bags choke & drown sea turtles that mistake the
  bags for jellyfish, mostly affects _?__
 Pollution--tumors
                       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
    General Information on Sea
              Turtles
 Adaptations-
 Shells-
 Egg laying-
 Hatchlings-
 Hatchlings‟ swimming frenzy-
    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
 Kemp’s 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)
    Turtle Conservation Efforts
   http://texashighways.com/slideshow/seaturtle/
   http://www.mcsuk.org/marineworld/turtles/turtles+in+trou
    ble
   http://www.mcsuk.org/media/turtle_flashvideo/index.html

				
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