Transcript STCB slideshow

Sea Turtles of Bonaire
Research, Conservation & Education
SEA TURTLE
CONSERVATION
BONAIRE
[email protected]
www.BonaireTurtles.org
tel. 717 2225 - 790 0433
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
What are sea turtles?
• Reptiles:
-vertebrates
-air breathing
-have waterproof skin
-lay eggs on land
What are sea turtles?
• Reptiles
• Evolved from terrestrial
turtle (tortoise)
• Archelon ischyros,
largest marine turtle,
known to have lived
70 million years ago
• Turtle species we see now have existed
for about 20 million years
Archelon ischyros
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Worldwide
7 sea turtle species
Hawksbill
Loggerhead
Bonaire
3 regularly seen species
2 rarely seen species
Green turtle
Olive Ridley
Found elsewhere
Kemp’s Ridley
Flatback turtle
Leatherback
Green turtle
Turtuga blanku
Chelonia mydas
Hawksbill turtle
Turtuga karet
Eretmochelys imbricata
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Where around Bonaire do the turtles live?
Some survey and tagging program objectives:
•
•
•
•
make an accurate count of turtles by species
locate the foraging habitats most used by turtles
measure how fast individual turtles are growing
determine how much turtles move around
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Sea turtle general life history
Turtle diving behavior
Depth (m)
• turtles living on reefs are active
during day, mostly resting at night
• surfacing every 20-60 min
• depth range of juvenile hawksbills
to 50 meters, adults to 200 meters
• leatherback turtles can dive to
depths >1000 m
Photo by Ellen Muller
Sea turtle behaviors
• Resting
• Mating
• other behaviors
Photo by Ellen Muller
• Feeding
Turtle migratory behavior
• where do turtles go after they
are done laying nests on Bonaire?
• two hawksbill turtles tracked in
2003 with satellite transmitters
• two hawksbills, one green and
one loggerhead tracked in 2004
with satellite transmitters
Satellite Tracking 2003 & 2004
‘Extra’
‘STINAPA’
‘Nautila’
‘Schillie’
‘Funny’
‘Tom’
Turtle Migratory Behavior
Satellite Tracking 2003 and 2004
Satellite Tracking 2005
• ‘Albert’ - male hawksbill
fitted with transmitter 09
June
• Captured off Ebo’s Reef
•Sponsored by the cruise
ship Freewinds
Photo by Steve Jarrad
Satellite Tracking 2005
• ‘Happy’ - female
loggerhead fitted with
transmitter on 24 June
at SW Corner
• Departed 29 June
• Arrived Vieques
Passage 18 July
• Swam over 1100 km
• Sponsored by the
Rotterdam Zoo
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Sea turtle longevity
• Sea turtles are slow growing
• 15-30 years to maturity is typical
• Adult turtles that we see may be
15-60 years old
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
• For juvenile turtles you
cannot tell males from
females by looking at
them
•Only when adult do the
males have long tails and
claws on their front
flippers
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Playa Benge
Playa Chikitu
BONAIRE
No Name
KLEIN
BONAIRE
Main sea turtle nesting areas
around Bonaire
“Pocket Beaches”
Lagoen
Klein Bonaire’s “No Name” nesting beach
Hurricane “Lenny” damaged many
Bonaire nesting beaches
Bonaire sea turtle nesting calendar
Primary
beaches
• Chikitu W.P.
• Benge W.P.
• No Name K.B.
• No Name K.B.
• Pocket Beaches
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Sea turtle nest
characteristics
Green turtle:
~100 eggs per nest
~80 cm deep
prefers open beach
Loggerhead:
~120 eggs per nest
~60 cm deep
prefers base of dune
Hawksbill turtle:
~150 eggs per nest
~50 cm deep
prefers under vegetation
Sea turtle nests hatch after
about two months incubation
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Turtles vulnerable to predation,
especially when small
Survival ratio example for stable population:
Hawksbill turtle female:
lays 150 eggs per nest
4 nests per season
one season every 3 years
12 year reproductive life (5 seasons)
-> 3000 eggs produced during lifetime
successful hatch rate of about 75%
-> 2250 hatchlings produced during lifetime
needs to produce 2 replacement adults (1 female and 1 male)
-> stable population survival ratio: 2250:2 = 1125:1
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
Turtles threatened by:
• exploitation at sea
(turtle meat, shell)
• exploitation on the nesting beach
• habitat destruction
• disease
(eggs, turtle meat)
(such as coastal development)
(such as fibropapillomatosis)
• fisheries by-catch
• pollution
(such as entanglement)
Fibropapillomatosis occurs in green
turtles at Lac Bay and Lagoen
• What are sea turtles?
• How many species are there? How many around Bonaire?
• Where around Bonaire do the turtles live?
• How do turtles live? What is their behavior?
• How old can sea turtles become?
• How can you tell the difference between male and female turtles?
• Where do turtles nest on Bonaire? When is the breeding season?
• How big is a turtle nest? How long until a nest hatches?
• What proportion of hatchlings will survive?
• What threats do sea turtles face?
• What can I do to help?
What you can do to help:
• Don’t pollute the sea
• Keep vehicles off the beaches
• Never buy sea turtle products, such
as “tortoise shell” jewelry
• Report any turtles in trouble around
Bonaire to us immediately
• Help out as a volunteer in our
research, conservation and educational
activities
• Become a member or make a donation
Visit us at
www.BonaireTurtles.org
Support Bonaire
www.SupportBonaire.org
Sea Turtles of Bonaire
Research, Conservation & Education
SEA TURTLE
CONSERVATION
BONAIRE
[email protected]
www.BonaireTurtles.org
tel. 717 2225 - 790 0433
Support Bonaire Inc.
www.supportbonaire.org