RID 2470 - ROTARACT CLUB OF GLYFADA

Sea Turtles:

Fossil records lead to the conclusion that sea turtles are contemporaries of the dinosaurs. Although dinosaurs disappeared, turtles continue to survive to the present date.

Out of the seven species in the world, only three can be regularly found in the Mediterranean (loggerheads - Caretta caretta, green turtles - Chelonia mydas and leatherbacks - Dermochelys coriacea). Of these three only the loggerhead sea turtle nests in Greece. The most important nesting beaches are in Zakynthos (Bay of Laganas), Peloponnesus (Bays of Kyparissia, Lakonikos and Koroni) and on Crete (Rethymno, Bay of Chania and Bay of Messara). The beaches of Zakynthos have an extremely high nesting density. The density on one beach (Sekania) may reach about 1500 nests per km, one of the highest in the world.

The loggerheads’ carapace is heart-shaped and has five pairs of costal scutes. The colour of the carapace is reddish brown but can be obscured by a covering of green algae. The plastron is pale yellow. Loggerheads tagged in Greece have been recovered over a wide area, up to 1500 km away, in Italian, Tunisian, Libyan waters suggesting purposeful non-random movement. Most of the recoveries are from the Gulf of Gabes in Tunisia and the northern part of the Adriatic Sea which probably indicate that these are the preferred wintering areas for loggerhead turtles. The most serious threats to loggerheads in the Mediterranean are tourist development of nesting beaches and incidental catch in fishing gear.

Threats to Survival:

The World Conservation Union (IUCN) has declared 6 species of sea turtles as endangered or critically endangered. The threats for sea turtles are both natural and man-induced.

Natural Threats: There are of course natural threats to the survival of sea turtles, their hatchlings and eggs. Weather is a prime factor. Wind, rain and cold and unnaturally high tides, all take their toll on turtles at all stages of their lives. Temperatures below 14°C stun even adult turtles. Beach erosion destroys nesting beaches. The natural enemies of eggs and hatchlings vary depending on geographical location. In Greece, foxes, dogs and occasionally jackals may dig up the eggs. Hatchlings racing for the sea are sometimes eaten by those animals as well as by martens and rats, or by birds like crows, gulls and cormorants. Once the hatchlings have reached the sea they may be devoured by large fish such as sharks.

Threats from Man:

1. Capture by fishermen for exploitation purposes (meat, accessories)

2. Poaching of eggs for consumption

3. By-catch in fishing gear resulting in drowning or being killed by fishermen.

4. Nesting beaches are dramatically shrinking because of development, especially tourist development.

a) Lights shining on the beaches disorient both nesting females and hatchlings trying to get to the sea.

b) Sand compaction due to vehicular traffic may disturb the balance of gases and their absorption by the eggs.

c) Beach furniture on the nesting areas often make an impenetrable wall that denies access to the back of the beach for nest construction.

d) Heavily trafficked beach paths, planting shade trees, or setting up umbrellas result in lower sand temperatures which has an impact on the incubation of the nest.

e) Human presence on the nesting beaches at night scares sea turtles trying to nest.

f) Sand castles and vehicle tracks may trap hatchlings in their race to the sea.

5. Pollution of the seas is yet a further threat. Turtles often mistake discarded plastic bags for jellyfish, tar balls or a chunk of polyethylene for something to eat. If they consume these foreign substances their intestines may become clogged and they may die.

Reference:
- http://www.archelon.gr/

Rotaract Club of Glyfada – RID 2470, GREECE