Between the Tides: In Search of Sea Turtles

Between the Tides: In Search of Sea Turtles

by George Hughes

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Overview

Much can be learned about the condition of the planet’s environment by looking at sea turtles; they have existed for more than 100 million years, and they travel throughout the world’s oceans. Suddenly, however, they are struggling to survive, largely because of harm that has been done to the planet’s oceans and beaches. This passionate account is told by an ardent conservationist who records his experiences while undertaking fundamental research. Including descriptions of the life cycles and fascinating facts about turtles, this book asks what their demise means for the human species. A remarkable story, it also highlights the active role South Africa has played in protecting its own seaturtle populations and researching the turtle populations in neighboring countries.

Product Details

ISBN-13: 9781431405640
Publisher: Jacana Media
Publication date: 11/01/2012
Sold by: Barnes & Noble
Format: NOOK Book
Pages: 276
File size: 5 MB

About the Author

George Hughes is the former CEO of the Natal Parks Board and of Ezemvelo KZN Wildlife. He is also the former chairman of the radio program "Talking of Nature" and the recipient of numerous awards, including a lifetime achievement award from the International Sea Turtle Society.

Read an Excerpt

Between the Tides

In search of sea turtles


By George Hughes

Jacana Media (Pty) Ltd

Copyright © 2012 George Hughes
All rights reserved.
ISBN: 978-1-4314-0564-0



CHAPTER 1

The Timeless Turtle


The privilege of walking along exotic beaches devoid of man on both moonlit and dark nights is given to very few. The excitement and wonder of finding, between the tides, sea turtles intent on nesting, is given to even fewer. I have been one of the lucky few.

One of the great myths about turtles and tortoises is that they attain great age, possess great wisdom and represent continuity, if not perpetuity. Many Eastern religions regard turtles as the foundation of the earth and such myths have been perpetuated by contemporary authors, such as Terry Pratchett with his Discworld series.

As far as sea turtles are concerned, there is proof neither of great age nor of great wisdom. Of the many thousands of turtles I have observed all over the world, I have been struck by the fact that very few display any signs of age. Size is certainly no indicator and, although there have been attempts to calculate age from rings in the humeral bones, it has proved impossible to ascribe turtles a scientifically defendable age from external characteristics. What are often visible are the scars from their time as hatchlings or as a result of later encounters with large marine predators such as sharks or killer whales – or sheer bad luck in trying to negotiate rocky approaches during periods of rough seas – but these are not any indication of age. Most researchers are confident, however, that painstaking research will reveal exactly how long sea turtles may live.

The late Prof. Archie Carr recorded some apocryphal tales of turtles found with inscriptions carved into their carapaces, which suggested that they had endured at least 85 years since being inscribed, but modern estimates fall somewhat short of that. At present we are certain, for example, that Maputaland loggerhead turtles take about 24 years to reach nesting maturity after entering the sea as hatchlings. We also know, from tracking females that return to Maputaland season after season, that these turtles can re-migrate many times – in individual cases these migrations occasionally span periods of some 25 years. Although there is nothing in the anatomy of nesting turtles to suggest age, our results would suggest that 50 years is not unreasonable for a female loggerhead and, considering the dangers facing a turtle every time it travels to nest, most turtles would do well to achieve it. But we may be well off the mark.

Many years ago, while walking along the Tongaland (which became known as Maputaland after 1975) beaches on a fairly bright evening, my fellow Thonga turtle-trotter, uMsombuluko, and I spotted a female loggerhead emerging from the sea. She was a black spot lying on the sparkling wash zone with just a hint of light reflecting off her still-wet carapace. Normally one would wait until the turtle was clear of the wash zone and then approach the animal from the rear to check for tags. She appeared to walk with patient deliberation and some awkwardness, however, so we decided to let her get a little higher up the beach before approaching. Perhaps we were just tired and grateful for a rest, as beach walking at neap tide was energy draining and really hard work on some nights.

We waited a long time, patiently watching her as she cleared the wash zone, entered the dry sand above the high-tide mark and eventually stopped well up the beach where her instincts told her that her eggs would be well clear of even the highest of high tides. She started to dig her body pit.

We laboured to our feet and quietly moved towards her from the rear, careful not to disturb her, and gently felt for a tag in order to ascertain whether she had been seen either this season or in any previous season. She bore neither a tag nor any trace of a callus suggesting that she had lost a tag. She was, as far as we were concerned, a new nester, perhaps coming ashore for the first time in her life. Untagged animals always caused a small frisson of excitement, so we eagerly dropped our packs and began to sort out the tagging and measuring gear preparatory to adding yet another unique female to our schedules of tagged animals. Having prepared our equipment, we switched on a torch and received a dramatic shock; she was the first and only loggerhead turtle I had seen, or have been destined to see, that displayed all the characteristics of great age – she was clearly a very, very old turtle.

She did not appear to have any spare flesh. Her skin hung in wrinkles of a size and depth that I had never seen before and at every exposed part of the body the skin drooped in long loose folds. What was more, the skin was free of the normal clusters of acorn barnacles so common on the majority of turtles. It was as if there was simply insufficient body to the skin for the barnacles to maintain a solid grip.

She ignored the pair of us and the torchlight, determinedly digging her body pit with steady sweeps of her fore-flippers until she reached the depth at which the top of her carapace lay level with the surface of the beach. We watched in fascination. This was no normal turtle and we did not want to disturb her, so we made no further moves to implement our normal procedures. Her every feature demanded respect and we somehow felt that this unique moment was to be savoured to the full.

Every tendon in her neck stood out sharply under the skin. Every head movement brought to the surface an array of tendons apparently unattached to visible muscle, but seemingly operated from within the carapace. It was like watching a marionette, but a marionette with almost no eyes. Close examination showed that her eyes were so deeply sunken into the sockets that they were barely visible and it was not possible to see the brown pupils so common to the species. It became clear that her every movement was laboured and each was taking a greater and greater effort.

At first sight, and clearly unkindly, we had thought her the most decrepit turtle we had ever seen. We thought that she was either very sick or suffering the after effects of serious wounds. Her probably extensive migration must have exhausted her energy reserves and she was clearly on her last legs. Our first impulse was to feel pity, for this animal was in a sad state.

How wrong could we have been? This was no sick animal worthy of pity but an ancient turtle whose lifetime became an object of excited speculation as we observed that her flippers, having moved steadily to and fro over goodness knows how many years, had worn half-moons in the outer edges of the carapace. At the deepest point, at least 10 centimetres of carapace had been worn away. We had never seen this before in Maputaland. The only explanation was that this turtle was of a great age, extensively travelled and making yet another visit to the nesting beaches to ensure the survival of her genes and her species. She had survived odds that are dazzling to contemplate. We sat in awe, amazed at her efforts, against greater and greater odds, to continue her line.

Speculation about where she had travelled, what dangers she had faced and how many times she had nested was both exciting and reverential; we watched her slowly complete her nesting hole and then settle, almost with an audible sigh, to lay her eggs with her now-exhausted rear limbs straddling the hole. After an unusually long time, she started the internal contractions that brought the eggs down into the hole in bursts of two to four. Long pauses followed each expulsion of eggs and it took her twice as long as normal to finish laying her clutch – which comprised more than 100 table-tennis-ball-sized, soft white eggs – and then she rested.

By now we were emotionally tied to the old female and we waited without impatience for her to fill the hole and disguise the nest site. We were enjoying the moment, fully realising that we were unlikely ever to see a similar animal again, when we were both surprised and shocked. Instead of filling the hole with sand, a series of spasmodic convulsions shook her and after some minutes we were amazed to see pink flesh emerging from her cloaca. By now we were riveted to her every move and minutes stretched into tens of minutes while she evicted her entire oviduct into the egg hole. Then she stopped and we sat there bewildered, having never seen or heard of such an occurrence before. We waited to see what would happen next.

After a lengthy pause, she reverted to the standard loggerhead practice of carefully lifting sand with her hind-flippers and placing it gently into the nest hole, sliding from side to side as she did so. After about ten such moves, she once again stopped, as if contemplating the next step of the process, before pressing down firmly on the sand to compact it and provide added protection for the eggs. Oblivious of the gradual disappearance of her oviduct, she carried on with her normal nesting process. With weary fore-flippers, she made a weak attempt to disguise the entire nest site. By now, however, she was obviously exhausted and after a long pause she clearly decided that she could do no more. She pulled herself toward the sea, tearing her oviduct from her insides and effectively ending what had obviously been a long lifetime of dedicated service to her species. It was a dramatic moment as we stood watching her walk back to the sea, probably for the very last time. There would never be another instruction from her hormones either to mate or to migrate; no instinctive urge would ever again cause her to leave the relative safety of her feeding grounds to emerge onto a beach.

It was a sobering experience. We wordlessly decided against tagging her, or even measuring her. She did not deserve any indignity. We slowly followed her down to the sea. We stood in the water and we watched as the first small waves swept the beach sand from her head and carapace. Then she paused, as if to take stock of her surroundings, lifted her head and peered at the sea horizon, slowly crawled forward and was swept from view by a large wave. She was gone.

After a contemplative silence, we went back to the nest and carefully removed the oviduct from the nest site, ensuring that no part of it remained with the eggs. Taking perhaps more care than we normally did, we covered the nest and disguised it thoroughly. Never had a clutch of eggs better deserved a successful hatching. I am sure that many of the hatchlings that eventually emerged are already continuing the duties of their mother.

In all the years that have passed since that night, I have never again witnessed such an incident and neither have any of my turtle colleagues in many parts of the world. I reflect on what I saw with some humility. The life of a productive nesting female sea turtle is not an easy one and although I have watched the emergence of countless thousands of hatchlings, I have never felt so close to a sea turtle as I did to that loggerhead female on that quiet night in Maputaland. She had completed her nesting ritual, not just for that clutch of eggs, not just for that night and not just for that season, but for ever, and departed to seek out the rest of her life freed from the vicissitudes of breeding. My own judgement is that she had done an extraordinary job and deserved some years of peace for having made her unique and full contribution to the continuation of her species.

It would have been nice to know exactly how old she was, but that will forever remain a mystery. Since then, however, many of us have laboured long and hard to describe the life history of sea turtles – and this book describes our endeavours.

CHAPTER 2

Exploitation Until the Twentieth Century: A General Background


Sea turtles are essentially prey animals and one of their basic survival strategies has been to produce large numbers of eggs per female for as many seasons as the female can manage. This is no trivial strategy, as most females produce over 100 eggs per clutch and some, like leatherbacks, can lay ten clutches per season. This is a total of over 1,000 eggs in a single four-month period. This immense labour can cause a female to lose almost 25 per cent of her body weight and drains the animal's resources to a point where many appear unable to endure more than one season of nesting. The strategy has, however, been very successful and, although it was developed well before the coming of humankind, it has allowed all seven extant species to survive one of the most savage attacks by a single species on another ever recorded.

In many parts of the world, early man discovered that the annual gatherings of nesting sea turtles were simple and threat-free opportunities to obtain high-quality protein. They killed the odd nesting female and collected and consumed the easily available eggs. While these early hominids were serious predators, their numbers were small, their lifestyle was nomadic and the impression that they made on sea-turtle populations was negligible.

They were not the only predators, however, and turtle rookeries attracted the attentions of many other terrestrial predators, from jaguars in South America to racoons in North America and dingos in Australia. In South Africa, side-striped and black-backed jackals visit the beaches nightly to dig up eggs and are joined by the Nile monitor and, more recently, the ratel or honey badger. All such predators were comfortably catered for by the turtles' strategy, which has been designed over millennia: overwhelm your enemies by sheer numbers.

When western man started to 'discover' new lands and conquer the oceans, it was necessary to overcome difficulties and threats hitherto never experienced. Sailors, right up to the end of the eighteenth century, suffered from the effects of a diet lacking in vitamins and fresh food. The sea turtle entered into this scenario and the previously tolerable influence of early man became life threatening and eventually wiped out some of the largest turtle rookeries in the world. Exploitation gradually grew to industrial proportions, which the turtles' survival strategy had never been designed to combat.

Sea-turtle rookeries were identified by the early explorers and their locations were noted as destinations for replenishing food stores. To make matters worse, they learned that turtles could last for months if given a modicum of care – such as being kept on their backs in the shade or in the hold and watered down regularly – and could be kept to be eaten on demand. The huge numbers of turtles at some nesting sites inspired understandable awe, so much so that Christopher Columbus named one Caribbean island group Las Tortugas (the Turtle Islands), which is now known as the Cayman Islands. The Cayman Islands eventually became famous as a stopover for ships plying the waters of the New World. The good news was that the turtles cost nothing. The bad news was that the system could not endure and there was worse to come.

Slavery in East and southern Africa was the domain of Arabs throughout the eighteenth century, and indeed well into the nineteenth century, until the British blockaded the main export port of Zanzibar in 1873. In West Africa, however, the slave trade became industrial and every Western nation with a respectable trading fleet indulged in slavery, which led to the development of what became known as the 'Slave Triangle'. European ships bearing materials manufactured in Europe would sail to West Africa where they sold their cargoes for cash to buy slaves or traded the materials directly for them. These evil transactions grew in proportion with the prosperity of the New World until millions of Africans were being exported through the slave markets of West Africa such as Gorée Island in Senegal, Ghana, Nigeria and Sierra Leone. Following the successful sale of the surviving slaves in the New World, the ships would load up with products such as sugar, tobacco and cotton and return to Europe, thus closing the Slave Triangle.

Feeding a few sailors on sea turtles gathered on rookeries was one thing, but providing free food for slaves packed into ships in inhumane numbers was another. Slaver after slaver called at Ascension Island in the mid-Atlantic to collect turtles to feed their captives. The negative impact of the slave trade soon began to manifest itself and the numbers of green turtles nesting on the island declined sharply. By the time slavery was outlawed, the island was no longer regarded as a source of turtles.


(Continues...)

Excerpted from Between the Tides by George Hughes. Copyright © 2012 George Hughes. Excerpted by permission of Jacana Media (Pty) Ltd.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

Table of Contents

Contents

Maps,
Preface,
1 The Timeless Turtle,
2 Exploitation Until the Twentieth Century: A General Background,
3 The Eleventh Hour?,
4 From the Beginning,
5 Tools of the Trade – Part 1: The Humble Tag,
6 Tools of the Trade – Part 2: The Satellite Tag,
7 The Search for the Lost Decade – Part 1: The Nuclear Threat,
8 The Search for the Lost Decade – Part 2: 'Isn't that one of your f---ing marked turtles?',
9 Amanzimbomvu to the Rescue and Other Tales,
10 'There's a dog nesting on the beach?',
11 'Sea turtles are not consummated in the market!',
12 ORI and the Fairy Godfather,
13 How Hatchlings Live and Die and Other Dangers,
14 Guiding Turtles to and fro and Other Wonders,
15 Aragonite Blue,
16 Politics and Turtles,
17 Conferences, Politics and Astonishment,
18 Sustainable Use and the Great Divide,
19 Enter the Mascarenes,
20 Mozambique: The First Attempts,
21 'A gross abuse of public funds!',
22 The Morning Chorus and Other Excitement,
23 Of Rats and Mermaids,
24 Mozambique: The Far North,
25 Madagascar: Of Turtles and Tombs,
26 Europa: A Superfluity of Animals,
27 Tromelin Island,
28 Among the Fairies: The St Brandon Islands,
29 Beaches and Miracles,
30 The Sodwana Declaration,
Photo Captions,
Acknowledgements,

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