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 turt
le that is a strict herbivore as an adult, Jaws
finely serrated, helps tear vegetation when eati
ng
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 ingred for Turtle soup, also E
ggs dug for food 1 nesting site left inCaribbe
an, 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

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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
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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 b/c 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
Other details mainly nest in Northern
SouthAmerica
Largest
Greatest Range
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Leatherback Sea Turtles
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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 allo
w It to get food from crevices In coral reefs
Pop 8,000 nesting females
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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 1x every 2-3 years
• Every 15 days 2-4x per season
• 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 b/w 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 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

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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 Est 7,500 nesting females

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Australian Flatback Sea Turtle

• Females nest 4x per season
• Each nest has 50 large eggs
• The eggs incubate for 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
• 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 Galapagus 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 inyo the
major ocean Currents and spend the first 4-5 year
s of their lives drifting Around on patches of sa
rgassum
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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