Flotsam and jetsam

Previously I have introduced Aldabra as one of the most pristine atolls on the planet, and certainly in the Indian Ocean. There is always a bit of bitter with the sweet. Rubbish wash out on the beaches here, a lot of it. It is certainly a less tasteful topic, but no less true or necessary than the sweet ones.

There are no large industries on Aldabra. There are no massive factories, no harbours, no airfields, and it is hardly populated. There are no shopping malls, and only fishing that can sustain the eight to sixteen people that live here at any given time is allowed. Yet, even on this pristine atoll, rubbish of all kinds can be found.

The persistent winds and strong currents wash an extraordinary amount of rubbish from all over the world onto the beaches that would otherwise be pristine. You can find nearly anything that floats on these beaches: Buoys, drums, gas cylinders, toy soldiers, toothbrushes, dolls, broken boats, masts from boats, FADs (Fish Aggregating Device), lids, containers, ...the list goes on and on and on. Most common of all are flip-flops, tons of it. I am talking about those trendy summer sandals that you buy for nothing and through away like it is nothing. During beach clean-ups we often joke amongst ourselves, and call it the flip-flop graveyard. But it is not really funny. Aldabra is the Mecca for green turtle nesting in the Indian Ocean. It is a terrible shame to see a majestic green turtle struggling to come ashore between all of the flotsam and jetsam, or abandoning nest digging because of some rubble obstruction buried in the sand.

It certainly made me re-evaluate the need for all this plastic. Do we really need all of it? Look around you. Absolutely everything contains it. Our sunglasses, fancy  ipods, cell phones, cameras, toothbrushes, televisions, and those trendy flip-flops, to name but a few. In fact, I am sure this laptop that I am writing from is mostly plastic. Will we ever really be rid of this wasteful pollution? Is there ever going to be hope for complete replacement of plastic with renewable materials? Or will green turtles on Aldabra (and everywhere else) be flinging away plastic soldiers long after human kind is gone?

Camping on the atoll

There are several camp sites on the atoll, which are all visited and used to continue the existing monitoring programmes. The data collected from these sites provide information over and above that collected from the base camp, for comparative studies  on the different areas on the atoll. For example, the tortoises on Piccard, the island where we are living, are much larger than those on any of the other islands, Malabar, Grand Terre, or Polymnie. We can then look at rainfall data or vegetation types to come up with reasons why the tortoises should be so much smaller on the other islands.

The huts at the camp sites are nothing more than a couple of sink plates nailed to a wooden frame, in the middle of nowhere. The more weather-beaten huts would fit in well amongst a stand in the Cape Flats (South African shanty town). Water is collected by guiding rain from the roof to rain gutters, and finally into containers. The floor is the ground. The beds are rickety bunk beds. The food cupboard is the rat and cockroach hotel. Showers are obviously open air, using a scoop. The light: the moon, candle or a torch. Toilets, are nearby bushes, everyone gets to dibs one. Washing basin: some washed out flotsam containers, that are cut in half. Dinner: most likely canned meat and rice; this features every meal during camp. Important to bring with you: mosquito net and repellent, suncream, water bottle, your field notebook and measuring equipment, and a stomach of steel.

At most of the camps we patrol designated beaches to count green turtle tracks, and nests. We do the monitoring first thing in the morning so that the tracks are fresh as possible, and minimal tracks have been washed away by the tide. Sometimes we are lucky to find a turtle that is still busy nesting, or returning to the ocean. When we find one that is still on terra firma, we attach metal tags with unique ID numbers to the flippers. We then take several measurements of shell and track size and note any damage caused by disease, boats or perhaps sharks, and of course whether or not the nesting was successful.

During the last camp I was sleeping outside, since I decided that the stars are a better roof than the corrugated iron sheets when it is not raining. After awaking and finding my way out of the mosquito net, I heard that flapping of sand as a female green turtle was closing her nest nearby. This was well before normal monitoring trips set off, but I could not miss out on the opportunity to tag this turtle after the fruitless attempt from the night before, when we were waiting until 23:00, but no turtles emerged. Tessa, a fellow volunteer and friend and I quickly made our way to the mother turtle in the pink early morning light. Tagging and measuring her was painless, other than the mosquitoes who seized the moment to get some fresh warm blood, and we were left to enjoy her triumphantly complete an all important phase of her life-cycle, as she struggled back to the water. She had done it: She deposited her approximately 100 eggs on the beach were she may have hatched 20 or more years earlier. Studies suggest that green turtles display great natal-philopatry (the behaviour to go back to the beach where they were first hatched from). It is one of the fantastic mysteries of life: How do they find their way through the enormous ocean to the same beach they were hatched from? Although we could not be sure that this was indeed the case with this green turtle, I would like to think so. This is one the on going studies to which tagging the turtles  contribute: When this turtle emerges on land again, someone might report the tag numbers the next time that the turtle is seen. The tag numbers can then be retraced to an international database which allows us to see where the turtle has laid eggs before. We had our cameras nearby, and were able to capture the moment. What a way to start the day!
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Brief overview of the biogeography and history of the Aldabra

Aldabra atoll is the earth's belly-button, for several reasons. This ring shaped atoll is near the middle on most maps of the world. It has been forgotten about since early discovery; and received much less attention since the late sixties. It also reminds us, that once the earth was once we were all born from an untouched earth, a beautiful place, before the days of pollution, habitat destruction and over-exploitation that has happened in so many other places on earth.

Aldabra is a dormant volcano, which has since collapsed in the middle. The rise and fall of the and sea level over several thousands of years has breached its walls, and today several millions of liters of water fills and drain the big central lagoon every day through four channels. The landscape is really rough - known as champignon (or mushroom rocks). It is old coral that has eroded over millennia. From the steep drop off, reefs fringe the atoll, bordered by steep champignon cliffs and a few sandy beaches. A thin line of sandy dunes fringed with restio-like grasses follow. Gradually the grass gives way to more shrub like bushes, some like the pemphis scrub, which are like large overgrown hedgerows.The vegetation then becomes more mixed, and eventually the mangroves that line the lagoon starts.


Inside the massive (ca 97 km^2) lagoon all sorts of charismatic animals, like green and hawksbill turtles, eagle rays and rarely, dugongs feed on vast sea-grass beds. The lagoon acts as a nursery to several fish smaller fish who hide amongst coral, champignon and mangrove tributaries. The reefs holds many large fish, including several species of rockcod, snapper, shark and ray. It has not been fished for years-and-years other than subsistence for the ca 15 people living here. Consequently the fish are very large compared to those in other parts of the world, where fishing pressures remove the largest oldest most fecund individuals. One regularly sees large groups of semi-resident spinner dolphins and and humpback whales which migrate to the tropics during their breeding season. In the mangroves, frigate birds and boobies nest next to each other, when not fighting over food during aerial acrobatics that leave you jaw-dropped looking on in wonder.


On land there are lots of giant tortoises - like the ones on the Galapagos Islands, but 100 000 thousand of them. The tortoises are the largest herbivore on the atoll, and maintain critical ecosystem functions. Their constant grazing and slow but sure movement from one grassy patch to the next sows the undigested seeds of a variety of over 50 species of grass, creating a mosaic patchwork of grass species.

There a lots of rare birds. The white throated rail, is a endemic sub-species, and is the last flightless bird in the Indian Ocean. Cheeky little buggers that will peck you on your toes if you are not paying attention to them. We have one, fondly known as Bruce, living under our house. He joins us at meal times for crumbs that may fall you your plate.

The atoll was once under English sovereignty, and later handed back to the Seychellois. During English reign, their were proposals to turn the atoll into a military base for allies. There was a public outcry from several biologists, including the best established scientific body in the world, The Royal Society.  Even Darwin marvelled at the real natural museum of evolution during his voyage on the beagle. How could the world be so short sighted at that time to overlook the natural value of today, one of the last remaining true wild places? It is thought that the proposal to "develop" Aldabra into a military base was finally abandoned for financial reasons, rather than public conviction. For whatever reason, thankfully,  Aldabra is a UNESCO world heritage sight, and an IUCN strict nature reserve, to be preserved indefinitely.