Ascension : Turtle Research & Conservation: 100th Anniversary of the Birth of Dr. Archie Carr - Release Date: 1st October 2009
Submitted by The Islander (Ascension Island Government) 01.10.2009 (Article Archived on 15.10.2009)
Archie Carr was one of the first prominent sea turtle biologists. He conducted a number of pioneering studies in the 1950-1980s that both added to our knowledge of the biology of sea turtles as well
Turtle Research & Conservation: 100th Anniversary of the Birth of Dr. Archie Carr
Release Date: 1st October 2009
Archie Carr was one of the first prominent sea turtle biologists. He conducted a number of pioneering studies in the 1950-1980s that both added to our knowledge of the biology of sea turtles as well as highlighting many of the conservation issues that face this ancient group. As well as producing a wealth of publications in the scientific literature, Archie Carr also wrote popular books that described both the biology of sea turtles as well as his exploits as a conservation biologist. In this way he brought the plight of sea turtles to the attention of the general public. Much of his work was conducted in the Caribbean where Archie Carr established a long term monitoring programme on the coast of Costa Rica which hosts an important population of green turtles (Chelonia mydas). However he also conducted pioneering studies at many other turtle breeding sites around the world, one of which was Ascension Island.
It has long been known that Ascension Island hosts an important nesting population of green turtles and indeed this population was exploited for many decades in the nineteenth and early twentieth century. For passing ships the green turtles provided an important source of food, but the turtles were also carried alive to far off locations to be the centre piece of banqueting feasts for European high society. However, while exploitation continued for a long period, little was know about this breeding population and basic questions such as where the turtles came from and the size of the population remained unanswered. After some initial trips to the island, Archie Carr was instrumental in setting up the first intensive monitoring of the nesting numbers in the 1970s. Archie Carr’s group recorded the number of eggs each turtle laid to assess the population’s reproductive output. These studies confirmed the magnitude of the population with several thousand nests each year during a season lasting from January to July and each nest containing around 100 eggs. Outside of this season the turtles were not at Ascension but their location was unknown. Adult green turtle are herbivores, feeding on sea grasses and seaweeds and so their foraging grounds are located in shallow inshore waters. The nearest potential foraging sites are 1000s of km away from Ascension Island on the coasts of Africa and South America.
Archie Carr initiated a programme to mark Ascension Island turtles with flipper tags and over time tag returns started to accumulate to show the destination of turtles after they left Ascension at the end of the breeding season. All the tags were returned from the coast of South America, mainly Brazil, over 2000 km away. Some tagged turtles were re-spotted at Ascension Island and these results showed that the turtles did not breed every year but instead there was an interval of several years between breeding seasons for each turtle. The picture was starting to become clearer. Green turtles foraged on the coast of Brazil but made the long arduous trip to Ascension Island every few years to breed during which time, away from their food source, they were starving. This huge investment in breeding meant that turtles could only make the trip every four or five years.
Carr was keen to record these amazing journeys of the turtles in more detail and developed some of the first rudimentary tracking equipment with turtles being equipped with floats attached to long tethers so that they could be visually tracked from the shore. This work highlighted the importance of fairly small areas close to Ascension Island where turtles congregated in-between their emergences onto land to nest. But the basic technology only allowed the turtles to be followed for short periods. The routes followed on their long distance migrations remained enigmatic.
Today conservation work continues at Ascension Island, building on the studies initiated by Archie Carr and his team. Monitoring of the number of nests is performed throughout the season. This involves walking the nesting beaches during the day and counting turtle tracks from the previous night. Of course the tracks may persist in the sand for several days, so an arduous part of the conservation work involves raking the beaches to remove tracks after they have been counted. Encouragingly the long-term monitoring has shown that the nesting population have increased over the last 20 years, with over 15,000 nests laid now in some years. This upwards trend in the size of the population is no doubt partly due to the fact that the nesting females are no longer killed for their meat and neither are their eggs harvested.
Archie Carr’s dream of being able to track the incredible migrations of Ascension Island turtles has also been realised. Nowadays small satellite transmitters are available that can be glued to the shell of the turtles allowing individuals to be followed for many months. These devices have revealed that the turtles follow incredibly straight-line routes on their Ascension to Brazil journey, guided by some sort of accurate compass system.
The legacy of Archie Carr’s work is that we now know much more about the biology of the green turtles that nest on Ascension Island and the population is thriving after long-term conservation.
Text by Professor Graeme Hays, Swansea University.
The set consists of eight different designs, 2 x 15p, 2 x 35p, 2 x 40p and 2 x 65p showing the conservation work taking place on Ascension Island.
Colour Photography Reinhard Mischke
Designer Derek Miller
Printer BDT International
Process Stochastic lithography
Stamp Size 28.45 x 42.58mm
Sheet Format 6 (3 se-tenant pairs) with pictorial border
Sheet Size 144 x 139mm
Perforation 14 per 2cms
Release Date 1 October 2009
Production Co-ordination Creative Direction (Worldwide) Ltd
Photographs of Archie Carr reproduced with the kind permission of Mimi Carr.
The help and assistance of Professor Graeme Hays, Swansea University and the Ascension Island Turtle Group is acknowledged with thanks.
These beautifully designed stamps and official first day covers will be on sale at the Post Office for a period of fifteen months provided stocks last. Overseas customers may view and purchase them by visiting out web site www.postoffice.gov.ac or enquires may be made to the Philatelic Bureau, Ascension Island Post Office, Georgetown, Ascension Island, ASCN 1ZZ or telephone + (247) 6260 Fax + (247) 6583