Ascension’s pride and joy and a must do if you are there in season.
For centuries, and probably much longer, green turtles have been coming to Ascension Island’s white sandy beaches to breed. At 3-4 year intervals male and female turtles migrate from Brazil to Ascension Island solely for this purpose. The arduous 4,000km round trip is an absolutely amazing navigational feat – rather than a chance landing on this isolated volcanic outcrop in mid-Atlantic. Turtles born on Ascension return there to breed – not just to Ascension but actually to the same beach they were born on. How they do this remains a mystery – theories range from olfactory (smell), visual and auditory (sound) cues, to innate maps and magnetic fields.
These green turtles are the largest of their species measuring around 1.5 metres in length and weighting up to 250kgs by the time they start breeding at the age of around 25.
The female turtles come ashore between January and May, some time after having engaged in an offshore courting and mating ritual that can last several hours. The turtles come ashore at night-time and while being reasonably agile and safe at sea (having made it to adulthood that is) they are clumsy and vulnerable on land and easily scared by light or movement hence the stern instructions not to shine bright lights on them. Take your photos in night mode or just after dawn when many will still be on the beach or returning to the sea.
In preparation for laying eggs the female turtle will seek a position well up the beach and dig a nest of up to a metre deep. She will then lay approximately 100 soft white eggs and cover them up. This process will be repeated several times in a season. Having laid their eggs the turtles will return to the relative safety of the sea – leaving behind an array of what look like tractor tracks down the beach to the sea and a beach that looks like it has been peppered with small bombs.
About 6-10 weeks after having been laid the eggs begin to hatch. An especially interesting piece of information (for me anyway) is that the sex of the hatchlings is determined by the temperature at which the nest incubates, and not genetically as is the case with most animals. Nests incubating at 29 degrees centigrade produce a 50:50 sex ratio. Above this temperature, a greater proportion of females are produced, and in nests cooler than 29 degrees, a larger number of males are produced. As the temperatures on Ascension tend to be 26 degrees, recent research has shown that most of the hatchlings here are female.
Having hatched, the hatchlings dig their way out of the nest – 3-5 days work – and surface in the dead of night and make a dash for the sea. How do they know which direction to go in I hear you say? They head towards the lowest and brightest horizon they can see and this, 99% of the time, is the sea – bright due to the reflection of the moon and stars. Occasionally they will head in the direction of a lighted house on the shore and one islander told me about how (not long after taking up residence on the island) she awoke to dozens of baby turtles on her verandah as she had left a light on overnight. She returned the turtles to the sea and henceforth hasn’t forgotten to turn all lights off before retiring of an evening.
Those that get their timing wrong and emerge too late to get to the sea in the dark, and alas many do, become prey for the frigate birds. Other predators include crabs and fish. Crabs “line up” along the beach close to the water’s edge and wait to pounce. Watching the crabs and the frigate birds at work just after dawn is a very depressing sight and is the reason you will see visitors escorting young turtles (which are about 3-4 cms long) to the sea at this time of the morning. I mentioned in my introduction entry to Ascension Island that I had developed a dislike for the birds on Ascension Island – now you know why. Off course when they get to the sea many other predators await them. Sadly, as I understand it, only one in a thousand hatchlings make it to adulthood.
Thankfully today (at least on Ascension Island) man is no longer a predator. This has not always been the case. See my separate review on Ascension’s Turtle Ponds for more detail on this.
Worldwide, marine turtles are still eaten (both the turtles and their eggs) and their shells are used in jewellery and other ornaments. Small scale harvesting by coastal communities is sustainable – large scale harvesting by outsiders is not. Other issues threatening the existence of marine turtles include incidental capture in fishing nets, loss of habitats and climate change. None of these are an issue on Ascension, yet.
It is estimated that around 4000 turtles visit Ascension Island each year and while all the 30 odd beaches on the island are nesting grounds the largest and most readily accessible for visitors to view this amazing animal is Long Beach right in Georgetown – a very short drive or less than 10 minutes walk from the Obsidian Hotel.
While the conservation office offers guided tours (around GBP 5) at 9pm a couple of times a week, the best time to go down to the beach is just before dawn – at this time flashless photos can be taken.
Address: Long Beach (and others)
Directions: Long Beach is in Georgetown