Chelonia mydas in Greece: a discovery

It was in summer 2017 that I went for a second time to Kastellorizo island, on an extended zoological expedition, looking for reptiles and fruit bats. Friend Kostas Chousalas was extremely obliging, giving to me the keys of his house, so I had a luxurious time to hang around and search the island. It was at that time that I observed the green turtles in the sea around the island, along with the loggerheads that were loafing around the tavernas. Loggerhead Turtles Caretta caretta are known from a number of places to have been accustomed to accept titbits and live in harbours. It is already known that in the main harbour of Kastellorizo there are some of these loggerheads that are regularly fed from the tavernas.

Caretta caretta in the main harbour of Kastellorizo

Caretta caretta exhaling at the surface to take a deep breath. They usually stay for some 4-5 minutes underwater, but can be much more.

The massive head of a Loggerhead Caretta caretta just under the surface

But while looking for turtles, I had a big surprise: apart from the loggerhead turtles that are quite common in Greece, there were some very rare Green Turtles Chelonia mydas. At the beginning I thought that there were only very few, but as I spotted more and more, I understood that in the small harbour these were the "common" turtles and not the loggerheads (which occupied the main harbour).

A Green Turtle Chelonia mydas surfacing to breathe. Trying to make photos of the turtles like this, I discovered that they were green turtles and not loggerheads

A number of features can tell apart the two species, but the easiest when you see them from afar is the small head of the green, the different shape of the head, the beak and the eyes, and the "keratin teeth" when you are near enough to see the mouth.

The keratin "teeth" can be seen here. The animal uses them for grazing sea grass

Unlike the Loggerheads, the Green turtles are herbivores and are not concerned for the titbits from the tavernas. They graze peacefully in the shallow small harbour which is like a lagoon, full of sea grasses (mainly Posidonia oceanica and Cymodocea nodosa). As you can imagine, I spent the next few days watching the turtles and trying to photograph them and to understand where they were going to graze. So I found that apart from the main water body, the animals came to extremely shallow depths to graze, and that was very usual. Big animals and very small ones (the size of a terrapin) were coming up to the shore to graze, when people were not there.

Adult Chelonia mydas grazing in less than half a meter of water, and less than two meters from the shore. I made the picture from a rock at the shore.

I swam and snorkelled with the turtles and was mesmerised by them. I decided to buy an underwater camera and return. The third trip was in spring of 2019 but there were no turtles to be found, all fishermen agreeing that the animals came from May on. So at last, in July 2019 I entered the water -the turtle-infested water- and swam again with them. Th experience was pure magic. The way they fly through the water is mesmerising. The fact that they were so beautiful and rare was only adding to it all.

That was my first underwater green turtle, a large male. You can tell it is male from the very long tail, used in copulation.

The large male heading to deeper water. That was the only male that I saw, all other animals being large females or smaller individuals, down to the size of a terrapin

The second day a large female approached me in about 10 meters deep water. Usually they were swimming far from me and not approaching me

Chelonia mydas resting at the surface. They only come at the surface to breathe and they stay for a minute. But it is magic when you are close to them.

A female in the crystal clear turquoise waters of the island. Green Turtle carapace is rounder than Loggerhead carapace.

The same female as above, in deep water, about 15 meters deep, with Bull Ray Aetomylaeus bovinus feeding under it on the bottom

The turtles were seen in water of 10-15 meters deep, feeding on the bottom, or coming to the surface to breathe, or in shallow water, again feeding on the sea grasses. When the animals were in deep water, it was easy to swim over them and then be very near them when they came to the surface to breathe. The turtles didn't seem to care for you at all and it was great to be just beside them.

On the contrary, when they were feeding in shallow 2-5 metres) or very shallow (0,5 -2 metres) water, they were very shy. The shallower the water was, the shier the turtles became.

The video below shows a green turtle cruising near the bottom

The video below shows a green turtle shoving sand with its front flippers to uncover the grasses on which it feeds

Feeding on the bottom

Shoving the sand to uncover sea grasses

In this picture can be seen the way it puts its front flippers to shove the sand in front of its head

After grazing for about 5 minutes, the turtle rises to the surface

When in deep water, the turtles had no fear of me and would surface very near me

Near the surface

Taking some breaths. They stayed for some breaths at the surface, for some seconds only.

Between breaths, hey would scan me and the sea below

After some seconds on the surface and some deep breaths, back to the bottom to carry on feeding

The following video shows an animal feeding on the bottom

And the next one shows a juvenile swimming

I spend the next two days in shallow water, sometimes just under a meter deep. When in deep water, the risk of been hit by a speed boat was very real. Many motor boats came dangerously near me. I also found turtles with scars from collisions, and turtle bones (ribs) on the sea floor. Implementing some speed limits and observing the places where boats are forbidden, is mandatory. There is heavy traffic of speed boats and sail ships in the small harbour where the green turtles live.

A speed boat passes very close to a green turtle, with the men being completely unaware of its presence

Many green turtles were found not in deep water but in very shallow one. Like this individual cruising over the sea grass Posidonia oceanica

In very shallow sea, the water was cloudy. One could see only at two meters distance. I would stand in the shallows with the water up to my knees and see a turtle just 5 meters away, but when immersed in the sea I could not see anything.

This is the sight that I would get when trying to approach a turtle in very shallow water. Neither of us could see the other, and when the turtle would see me, it was gone in a second

The solution was to forget about the animals that were grazing in very shallow sea (o,5-2 meters) and head to deeper water (2-5 meters). There the visibility was better and the turtles more relaxed when approached.

A juvenile green turtle

Exquisite patterns on the back of the juvenile

female in 3-4 meters deep water

That was the seascape in about 5 meters deep sea, with the turtles crisscrossing it. Underwater meadows of the sea grass Posidonia oceanica

Amongst the green turtles I found only one loggerhead, a massive male. Here is the first time I saw it, sleeping at the bottom.

Getting closer, I saw it sleeping with the head tucked in the sea grass and the tail bent. A sucker fish Echeneis naucrates can be seen on its side.

Beautiful green turtle at the underwater plains

And another, younger individual. Can be seen the patterns and the indented carapace

Where in deeper water I would observe feeding, in shallow water most of the time I would see active animals cruising from place to place. In one occasion I saw feeding and 2-3 times I saw individuals like this one, just resting on the floor. A sucker fish Echeneis naucrates is also seen here. And unfortunately, the scars of a propeller that had once injured the turtle.

I am not quite sure what they are, but in about 2 meters deep, one can see submerged man-made structures that once were over the surface. Probably the fortifications of a harbour or town? Seeing the fish and turtles swimming over them, brings an eerie feeling of distant past, or, for me at least, of distant future, when man is long gone and turtles roam over his ruins

Roaming here and there, I happened to stumble on this scene where there are three different animals in the same frame. On the left there is a Loggerhead turtle going to the left (the only one in this place, the one I met sleeping), on the right there is a Green Turtle going ahead, and in between there is a very small animal where you can see two white spots. The small green turtle is not very well visible, but you can see the barnacles on its back. See next photo

This is the very young individual with the barnacles on its carapace

The big male Caretta caretta surfacing

After some time wandering, I found again the big Loggerhead, again resting on the sea floor

But it was a shy animal, here it is departing again

On the last day I was very lucky to photograph a green turtle eating Posidonia oceanica at close range. It was in water not more than 1,5 metres deep, and I was lucky because I was behind some sea grass. The animal was relaxed on the floor and started eating

Grazing the sea grass. Usually the turtles were very shy in shallow water and I had only this chance to photograph one feeding

The discovery was very important because Green turtles are globally threatened and the Mediterranean population even worse. And of course because this is the first feeding ground to be found in Greece with so many turtles of any age and size congregated in such numbers. This led to a small article in Herpetological Bulletin, published by the British Herpetological Society :

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