Capturing the Diversity -Night walk on the beach

It was with great joy that I finally got a trip to Ascension Island in the March.  The Conservation Office was now headed up by Nicola Weber and her husband Sam.  I’d met them first when I taught a short course in GIS down at the University of Exeter campus near Falmouth, where Brendan was now a professor.  The debate about Ascension’s future had settled down somewhat, although many would say it was a stagnation rather than a settling.  There was to be no belonger status, the creation of an airport at St Helena was changing the dynamics for Ascension too.  It had meant that there were areas of the island in decline.  Fewer people were being contracted by the big companies on the island, which meant the population had dropped by about 15%.  The lack of options to be belonger or own property on island had forced several of the little entrepreneurial businesses to give up – even Tasty Tucker had shut.  The one potential bright spot on the horizon was that Ascension was being promoted as a living laboratory – a place where geologists and biologists, maybe even astronomers could come and do science, and there was a noticeable increase in supporting tourism with the arrival of more cruise ships in Clarence Bay.

Along with support from the likes of Exeter, RSPB and Kew Gardens, the Conservation Department had expanded. They now had offices and laboratory space right through their building, and one of the big elements was to construct Biodiversity Action Plans for the key species.  I was brought across to troubleshoot some problems that had been experience with the databases, which after so many years good service, were getting old and clunky, but still provided a fantastically long record of biology and could churn out useful maps and statistics.

On the first day there, Sam chatted casually about the fact he was going to conduct a turtle tour that evening.  My eyes lit up and I asked if I could come along.  He could not believe after so many visits that I had never been on one.  So I explained the timing problem.  With about half a dozen others, we turned up at Conservation with head torches with red tape over them (as they disturb the turtles less when laying),  had a brief talk about the green turtle from Sam, then took the Land Rovers down to the car park at the end of Long Beach, switching out the headlights as we pulled over the hill and on to the beach.

Sam used some night vision goggles to see if there was much activity. It was actually getting towards the tail end of the egg laying season and he didn’t expect to find more than a few each hour up there.  It didn’t take him long to spot some sand being flung in the air.  We trooped off walking along the road at the back of the beach.  Once Sam thought we were in line with the female, he led the way onto the sand.  Walking across here was difficult enough in the daytime, but with only a few dim red lights waving around you had to watch your step.  Not only were you heading up and down the sides of the green turtle nests, and they were deeper than I remember probably because many were fresh and the wind had not yet blown sand back in the depressions, but they were also soft spots in the sand as well as hard, again probably due to the excavations of the female turtles, and your foot could sink above the ankle with each step.

But eventually we got close, and we could hear the grunts of a turtle.  We appeared to have arrived just at the moment of laying; which was useful as the turtle was far less likely to be disturbed.  Turtles are very susceptible during the early stages of nesting to being spooked, causing them to turn back without digging, or leaving a half finished hole.  Once the laying starts, as long as you are quiet and careful not to get in front of her, she goes into an almost trance like state and is unlikely to stop.  Sam focused his red torch on the back end of the female and we all stood behind this so as not to disturb the turtle.  We watched her large floppy ovipositor dip into the deepest part of the hole she had dug.  Shiny white eggs came gently out the end and piled up softly in the sand.  After a few minutes the pile had probably 60-70 eggs in there; Sam was surprised as often it could be a lot more.  But she stopped there and began an incredibly delicate operation with her back flippers.  She would reach wide of the eggs, scoop up sand and gently cover the pile of eggs, sculpting a smooth shape as she did so. She repeated this operation several times, producing a tough casing within which the eggs would have some protection.  I had always wondered how eggs survived on these beaches.  I had always considered green turtles to be the clumsiest of the species.  Whereas I’d seen hawksbill nests hidden away at the beach head, greens didn’t seem to care where they laid their eggs, and I had seen several waterlogged nests in Anegada all that time back in BVI.  Many people on Ascension had said that several green turtle nests might be exposed when another turtle decides to burrow, tens of eggs flung out onto the beach with the rest of the sand.  Here at least was evidence that the nest laying was more calculated.  Maybe this nest would not survive a direct attack, but maybe the weight of another female heading further back on the beach will not crush the eggs.

The Chamber completed the turtle changed completely.  Instead of the delicate mother and sculptor she became the backhoe.  The huge front flippers were used to throw as much sand in the hole.  Now Sam told us we could take more photos and the red torch light was not so necessary and we watched for many minutes as the turtle filled in the nest.  The effort it took to do all this was clearly completely exhausting.  She huffed and puffed with every heave of those giant fins, and she had to stop several times to summon up her remaining energy.  You had to consider that this was probably one of only two times a year this female would come on to land.  She had evolved to operate efficiently in the sea, her huge carapaces protected her from her enemies down there, as well as the pressure of the water, her flippers were made for swimming not walking or digging.

But this urge to create the new generation brought them back on land year after year once they were fully mature.  We all watched with anticipation of the moment when she would complete.  It appeared the nest was covered up, but now she continued to fling buckets of sand all over the place – we had to keep jumping out of her way.  Then she lurched her shoulders forward and began to drag herself out of the nest.  Again this was no quick operation.  Being on land for a couple of hours, carrying the eggs up the beach, digging the nest, dropping them in and refilling the nest had taken its toll.  She’d take a few steps, pause, breathe and look around, then continue on again.  We left her to it.  My first green turtle egg laying.

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