In Ascension we spent a lot of nights on the beach. Around the island lives the second largest breeding population of Green Turtles (Chelonia mydas) in the Atlantic Ocean with 2.000 to 4.000 individuals and up to 25.000 nests per year. For us it is a rare opportunity to observe this big turtles very closely in and out of the water.
One of the nights was very special. It was raining and we were the only people on the beach and found a place, where we were surrounded by four digging turtles. We were sitting in between and listening to the noise of their digging and long deep breaths. At the same time five more turtles were just coming out of the water and starting their long way up the beach. At first we did not know if we should move or stay put so to not disturb them. We decided to keep sitting and wait where they would go and to finally observe them when they were ready to lay their eggs.
After the numbers of the turtles decreased rapidly in the 19th and early 20th century, they were mainly eaten, the population is now one of the only ones of the world which is increasing since the research started in 1977. In German the Green Turtles are called Soup-Turtles. That is because those turtles were very popular for their meat with the sailors and people who had to stay on the island. At least there was a law that they had to wait for the turtles to lay their eggs first and only afterward were allowed to turn them on their back. Now they had plenty of time to move the turtles to the so called Turtle Ponds, small pools, where they were kept sometimes for months. You can still see them in Georgetown. Every week one turtle was killed and eaten. Lots of them were also shipped to England, where turtle soup was a delicacy with the nobility. The last turtles were eaten in the 50ies and 60ies. Now the Green Turtles, like all the other marine turtles, are protected. On Ascension you have the special opportunity to see them during their mating as well as laying eggs and later in the year observing the freshly hatched young turtles in the months between December and May.
The main nesting beach - Long Beach with app.10.000 nests per year - is right next to the main village Georgetown. There they put up signs where you can read about the turtles and how you are supposed to behave when you want to see them nesting at night. After the sunset the first turtles are starting to come on the beach. One can see the dark shadows of their big bodies from far away on the bright beach. With an unbelievable effort, since they do not feel their weight in the water, those huge turtles, measuring up to 250 kg and 150 cm, move slowly up the beach. On a place behind the high water line they start to dig a big hole where they throw the sand a few meters away. After that they dig a smaller hole with their back flippers, the so called egg chamber, and start laying their 120 to 140 eggs. After they finish with laying their eggs they close the egg chamber carefully and then move lots of sand on top of that, so that you do not know where the egg chamber is situated after they are finished. The turtles seem to be more and more exhausted and are happy to be back in the water after 3 hours, so they do not feel their weight anymore. Every female turtle comes an average of six times in an interval of two weeks on the beach and so lays about 720 to 840 eggs in one season. If the hatched turtles are lucky one of them (in average one of 1.000 to 10.000 eggs) survives until the age of 25, when they will come back here to breed. Because they have to travel very far they only come every 3 to 4 years. Normally they live on the coast of Brazil where there is enough seagrass for them to eat, their main food next to algae. To breed and lay their eggs they travel up to 2.000 nautical miles in 5 to 6 weeks. Exactly the same way we now sail towards South Africa and Brazil. During their whole time in Ascension they do not eat anything because there is nothing for them to eat. They have to fast for almost half a year before they are back at their feeding grounds and can eat again.
The small turtles hatch after about 6 to 10 weeks and after they reach the water swim for 24 hours out on the open ocean - called juvenile frenzy. There they stay until they are about the size of a dinner plate where they turn up at their feeding grounds on the coast.
The mating often happens in front of their nesting beaches, in our case directly at our anchorage. In their loving embraces they sometimes collide with the boats at anchor with a loud bang. We have never seen as many turtles and we encountered them everywhere over and under water. The females often just lie somewhere at a depths of 20 meters and rest for their next beach trip. The males are more curious and active so we often see them when snorkeling or diving around Ascension.
Currently scientists are looking at the sexes of the freshly hatched turtles. Because the sex is decided by the temperature of the nest the scientists believe that the temperature of the sand will get higher because of the climate change and so the relative proportion of female and male turtles will change over time. Is the temperature under 29°C there are more male hatchlings, is it higher there are more female ones. Also the color of the sand has an effect, so more females than males hatch on the beach in North East Bay, in the north of the island, because the sand is darker. If this is true there may be effects on the whole population. But it can only be done in long term studies. At the moment everything is good and we hope that the population of Green Turtles will continue to increase even though there are less and less feeding grounds around Brazil. Hopefully a lot of people will have the opportunity to spend one of those magic nights with the turtles on the beaches of Ascension.