Caretta Caretta the sea
turtles
Sea turtles have been swimming the oceans
and seas of our planet for over a 150 million years. Contemporaries of
the earliest dinosaurs, they appeared long before mankind did. After having
survived climatic and geological changes sea turtles today face extinction
due to uncontrolled exploitation of the environment by man. Sea turtles
spend almost all their life at sea, but their survival depends entirely
on specific beaches where the females lay their eggs. Most of the turtle
beaches world- wide have been destroyed or are under immense human pressure.
Sea turtles are reptiles biologically
adapted to a marine environment. They breath with lungs and their soft
inner organs are protected by hard upper and lower shells, known as the
carapace and the plastron. Eight species of sea turtles now live on the
earth. Three species live in the Mediterranean: the leather back turtle
Dermochelys coriacea; the green turtle Chelonia mydas; the loggerhead turtle
Caretta caretta. Only the green and the loggerhead sea turtles still reproduce
in the Mediterranean.
Today, Greece hosts last major
habitats for the Caretta caretta in the Mediterranean: Crete (Rethymnon,
Chania), Peloponnese (Lakonia, Kyparissia) and Zakynthos.
On the island of Zakynthos,
in the Laganas Bay is existing the last important concentration of loggerhead
nesting sites in the Mediterranean with an average of 1 300 nests on 5
km of beaches.
On its present form the Caretta
caretta has existed on the earth for 80 million years. The carapace of
the adult Mediterranean loggerhead is approximately one metre long and
90 centimetres wide.
Each time the female Caretta caretta returns
to lay her eggs (from beginning of June through the end of August) she
does so on the same beach she was born on. She comes ashore at night and
pulls herself to the upper part of the beach where she digs a hole and
lays up to 200 eggs before returning to the sea. The same turtle may return
approximately 15 days later to dig another nest and she may repeat this
for a third or even fourth time in the same season.
The eggs must remain undisturbed
in the warm sand for about 2 month before they hatch out. When the eggs
hatch, the hatchlings remain in the nest for several days to absorb the
yolk sacs. From late July, hatchlings start appearing. They dig their way
out of the nest usually emerging during the night or very -very early in
the morning and they make their way down to the sea. The race of the hatchlings
from their nest to the sea is crucial for their biology.
Although a female sea turtle
may lay hundreds of eggs each summer, only very few hatchlings will survive
to adulthood: only one out of a thousand will reach reproductive age of
30 years.
The nesting beaches of Laganas
have been declared as specially protected areas for nature conservation
and a National Marine Park is underway.
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For more information about the sea
turtle go to
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*information
from the sea Turtle Protection Society of Greece and WWF