A Turtle Made It To The Water

The ancient stones are not the only silent witnesses of history. The body of a thousand-year old olive tree or sometimes sea turtles that made the same waters their home for millions of years swimming in the shimmering blue Mediterranean have the same effect. As the waters of the Mediterranean witnessed civilizations, wars, and love stories through the ages, the sea turtles were also part of this history. For an estimated 110 million years, this species, which has been a part of nature since the dinosaurs, shared the same seas and coasts long before human beings. Currently, there are seven different sea turtle species around the world and they all face the threat of extinction. Two of these species regularly visit the Mediterranean coasts to nest. Apart from Caretta caretta and Chelonia mydas, the leatherback turtle, daytime nesting turtle and hawksbill turtle have also been seen on these coasts, even if very rarely, for feeding or having accidentally arrived in the Mediterranean.

The sea turtles are relatives of a group of reptiles but spend almost their entire lives in the sea, having adapted to life in the water. The upper shells, called carapace, are not shaped like a dome as in land turtles, and are more suited to swimming. Since they are larger than freshwater turtles, their upper carapaces are a flatter, aerodynamic shape. In all species except one, this upper carapace is covered with large keratin scutes. The number of rings on the scutes gives an idea about their age. When the hatchlings come out of the eggs, they are usually in uniform and dark colors. As they grow, the carapace takes characteristic colors and different patterns appear on the scutes. The lower carapace, called the plastron, also consists of keratin scutes. The number of scutes on both the lower and upper carapace along with their patterns are used to identify species. Other features used in identifying species include the number of prefrontal scales in the region on the nose between the eyes and the skull structure. Another important feature is that, unlike the land turtles, sea turtles are unable to withdraw their heads into their shell.

These sea creatures, with legs that end in flipper-like feet, have different numbers of sharp nails. With flippers supported by strong muscles attached to the lower carapace, they are able to move through the sea with amazing elegance. Their tails also serve as rudders. The tails of the male sea turtles are quite long while the tails of the females are just slightly longer than the opening at the very back, called the cloak. This allows the tail not to get in the way during mating. The nails are also used during mating to hold each other firmly.

Though they spend most of their lives in the sea, the sea turtles still need to rise to the surface at regular intervals to breathe because they have a respiratory lung system. In such times, the hatchlings can become prey to birds. Adults may also face dangers such as boat propellers or fishing rods. Since the spine and ribs are attached to the carapace, the blows taken to the head and carapace can be lethal.

The sea turtles have highly developed smell and vision senses, however we cannot say the same for their hearing because the nostrils shut down under water with a special structure and the water is prevented from entering the lungs. Their vision is three-dimensional and they perceive both color and brightness well.

Instead of teeth, the sea turtles have sharp keratin protrusions called the rhamphotheca on the jaw, which resembles a beak. Some species are only herbivorous, while others are carnivorous. Naturally, the rhamphotheca structure has a morphology suited to the feeding of the species, and those in the herbivores are not as sharp as those of the carnivores. The carnivores can chew almost all shellfish with their strong jaws. And their favorite food is jellyfish.

The sea turtle’s life adventure begins in its nest buried under the warm sand.

Unfortunately, they sometimes swallow plastic bags thrown into the water, fishing nets and lines, mistaking them for jellyfish. Herbivores are very effective in preventing excessive algae growth. They secrete the excess salt they take in from sea water with the help of the glands in the back of their eyes.

The life story of a sea turtle begins in the nest buried under the hot sand. The egg, which the mother lays in a carefully selected spot on the beach and then covers with aweinspiring care, is warmed by the hot sand and has an incubation period of 6-10 weeks. The average nest temperature in the middle of this period determines the sex. Generally, in temperatures below 30 °C, the hatchling becomes male and in higher temperatures, it’s female. Eggs are a valuable nutrient for several animals. Foxes, raccoons, crabs, seagulls or dogs that dig up sand can damage the eggs. If all goes smoothly, the hatchling that completes its development at the end of this period comes out of the egg and reaches the sandy surface to arrive at the sea in the cool of the night. However, it is not that simple because there are hunters waiting to prey on these hatchlings that are about to take their first big test on this short journey. There are also obstacles and pitfalls on the way that they may not be able to overcome with their tiny flippers. A hole in the sand or an ordinary tire mark can pose a very serious danger. Any light that is brighter than moonlight can also cause them to lose direction. They must make it to the sea overcoming the hunters and other dangers that come their way before the sun rises. Otherwise, they run out of energy and are faced with the danger of drying under the hot summer sun.

Those that make it to the sea instinctively swim non-stop to reach the feeding areas. All the energy they have up to that moment comes from the nutrients inside the egg. They are not only unable to feed until they reach the safe areas, but they are also unsafe against all kinds of danger in the sea as well. They are tested with preying sea creatures, garbage, fishing nets and lines as well as starvation. Those that can grow to the size to be able to defend themselves only reach reproductive maturity in 25-30 years and then return to the beach. When the weather begins to get warmer, they go to the beaches where they were first hatched to nest. Encountering male sea turtles at the beach is a very rare situation because it is very difficult to carry their already heavy bodies on land. Since they are used to living with the buoyancy of the water, gravity on land is too high. Furthermore, when they stay too long on land, the shelled body causes pressure on their lungs and it becomes difficult for them to breathe. This species lays eggs every few years, and when she does, she doesn’t settle with one nesting. Females return to the same beaches every 2-3 years and most nest 2-4 times during the years of nesting.

The mother watches the beach from afar and when she decides there is no danger, she goes ashore to look for a suitable spot. When she finds one, she uses her rear feet skillfully like scoops and creates a nest. She lays the eggs in the plump vase-shaped nest and then covers it with sand. She even throws some more sand on it to make sure that it is hidden well. We learn almost everything we know about sea turtles from research on the turtles that come to nest, the hatchlings and the nests themselves. But what we know about their life and behavior in the sea is quite limited. The feeding areas of some of these turtles are very far from where they nest. We know that they follow certain migration routes. These jour neys can be partially tracked with the help of satellite monitoring devices fitted on their shells. The studies are important in terms of preserving the species and better understanding of their biology. The protection activities prevent damage to the eggs through regular monitoring of the nests and ensure that as many hatchling as possible reach the sea. Local people, tourists, touristic facilities and administrations are all informed.

The young turtles that are injured or need help are treated. And yet, on average only one in a thousand eggs can reach the age of reproducing. The sea turtles live in all the regions with mild climates across the world and nest in relatively pristine beaches with suitable sand. The Mediterranean is an extremely important nesting area. And many of the countries by the Mediterranean have nesting beaches. Turkey is among the countries with the highest number of nesting beaches and the most protection activities. The nesting beaches and the nesting turtles are protected under the Bern Convention and CITES.

Currently, adult turtles are hunted or eggs are gathered for nutritional purposes in some countries. The shells are used to make souvenirs and their fat is also extracted. The Ecological Research Society, EKAD, is one of the several working groups that strive to alleviate the negative effects of human action on the turtles and has been operating in Belek, Antalya for thirty years.