Sea turtles
Crete is one of the most important places for the reproduction of the threatened
loggerhead sea turtle (Caretta caretta), which is very famous throughout Greece.
However, there are more sea turtle species found in the seas of Crete, which do not nest
on the island. These are the green turtle, the leatherback turtle and the hawksbill sea
turtle. All sea turtles have lungs, but can hold their breath for a long period under water.
Loggerhead sea turtle (Caretta caretta)
The loggerhead sea turtle (scient. Caretta
caretta) is the most important sea turtle
species of Greece, which is strictly protected
by
the
Greek
laws.
In
Greece,
two
organizations are involved in the protection of
sea
turtles,
namely
ARCHELON
and
MEDASSET , actually doing a great job.
The caretta turtle has a hard shell with 5 scutes on each side and its length extends to
100-120cm. Its weight usually reaches 100-150kg, but sometimes exceeds 450kg and the
turtle lifespan is 47-67 years. It feeds mainly on jellyfish, molluscs, crustaceans, and rarely
with algae. Unfortunately, a large number of turtles lose their life by swallowing plastic
bags, confusing them with jellyfish.
Crete is one of the most important places for Caretta caretta breeding, as hundreds of
loggerhead turtles lay their eggs on the island’s sandy beaches every summer. That's why
associations for the protection of the sea turtles operate in the northern beaches of Chania
and Rethymno cities, and in the Gulf of Messara, where the birthrates are higher than in
other beaches of the island.
The female turtle approach the shores of Crete only for giving birth, every 2-4 years,
from May to September. This is the time when beaches are filled with people. Once it finds
a beach with no lights, it comes out in darkness and gives birth to 20-200 eggs, which are
buried in the sand. When eggs hatch (after 2 months) the young turtles head to the sea.
The female turtles live in the open sea till they become mature and return to the same
beach to lay their eggs.
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The problem with the life cycle of turtles is that the deterioration or destruction of the
beach where they were born makes them actually incapable of reproduction (as they
always lay their eggs on the same beach). For this reason, on beaches where turtles
usually reproduce, it is not allowed to use lights, speakers, driving in the sand and walking
in the evening, so as not to disturb turtles.
In Crete, turtles lay their eggs on all the sandy beaches of the island, so it is advisable
to avoid evening walks on the beach during these hours. Also, if you locate a nest, you
must call the relevant association and mark the spot temporarily, so as to avoid walking
there. When informed, the association ARCHELON places metal cages over the nest.
Also, for those interested, ARCHELON accepts donations and volunteers to support the
association’s activities.
Leatherback turtle (Dermochelys coriacea)
The
leatherback
turtle
(scient.
Dermochelys coriacea) is the largest reptile in
the world, with its shell growing up to 250cm
and its weight, sometimes, exceeding 900kg.
Infrequent appearances of the species have
been reported in Greece (and in Crete), while
there has not been reported any case of
breeding on Greek beaches.
The leatherback turtle takes its name after its shell, covered by thick leather, rather than
hard scutes, as the other sea turtle species. It lives permanently in the sea, usually in very
deep and cold waters (up to 1200m depth), where it feeds on jellyfish and invertebrates. Its
blades remind of paddles, helping it move very fast and to travel vast distances.
Like other turtles, the leatherback female turtles come ashore every 1-4 years just to
give birth. The females dig a deep pit in the sand and lay 80-120 eggs therein, up to 12
times in the same breeding season. The buried eggs hatch after about 2 months.
Unfortunately, thousands of leatherback sea turtles lose their lives every year, after
eating plastic bags that look like their favorite food, jellyfish.
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Green Sea Turtle (Chelonia mydas)
The green sea turtle (scient. Chelonia
mydas) has been met very rarely in the Greek
seas and there are no indications for nesting
on Greek shores. It is also found rarely off the
Cretan seas and is the largest sea turtle with
hard shell in the world.
It is the only herbivorous sea turtle, feeding
primarily on algae. Its name does not come
from the color of the turtle, but the color of its fat due to its algae-based diet.
It has a hard carapace with 4 scutes, with beautiful black, gray, brown and yellow
shades, while it has a relatively small head. Its length can exceed 120cm, its weight
usually reaches 100-150kg, and can live up to 80 years.
It lives permanently in the sea and the females come out on the sandy beach, where
they were born, every 2-5 years, to lay 50-240 eggs. The eggs hatch after approximately
2-2.5 months. In the Mediterranean Sea, the green turtles breed in the eastern coasts
(south-eastern Turkey, Cyprus).
This species is seriously threatened with extinction worldwide, as it is hunted by
humans for its flesh. Moreover, many newborn turtle lose their life after swallowing plastic
bags, considering them as food.
Hawksbill sea turtle (Eretmochelys imbricata)
The
hawksbill
sea
turtle
(scient.
Eretmochelys imbricata) is an endangered sea
turtle species found primarily in tropical seas.
Some of them (very few) have been met in the
open sea south of Crete and in other
Mediterranean areas.
The hawksbill sea turtle is perhaps the
most beautiful sea turtle and is named
“tileturtle” by Greeks because its shell is composed of scutes that resemble tiles. The
carapace has a length of up to 110cm and weighs 125kg. It feeds mainly on jellyfish and
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other marine invertebrates. However it is omnivorous species, as the juvenile turtles seem
to prefer vegetable food.
Females approach the coasts every 2-6 years, digging deep pits into the sand and lay
50-200 eggs, up to 4 times in the same reproductive period. The eggs hatch after about 2
months.
The hawksbill sea turtles are eaten in some countries. Moreover, their carapace is the
main source of articles of natural celluloid. Hence, fishermen often kill them or remove
their carapaces while still alive. These practices threaten E. imbricata populations
with extinction.
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