Satellite Tracking of Sea Turtles

 A project undertaken at the Centre for Indigenous Natural and Cultural Resource Management, and supervised by R Kennett

 Green turtles are renowned for their long-distance oceanic migrations between nesting beaches and feeding grounds, spanning hundreds and even thousands of kilometres. These migrations often traverse national and international boundaries, requiring regional cooperation in the conservation and management of this endangered species. Understanding migration behaviour and routes, and identifying the coastal communities and other stakeholders who share responsibility for green turtles, is a key step in developing regional cooperation.

Green turtles are an important natural resource to the Yolngu, the indigenous people of north-eastern Arnhem Land, who have long held spiritual and cultural responsibilities for the large numbers of green turtles that nest on their beaches. Yolngu have been engaged in a sea turtle (miyapunu) conservation and research project since 1994, combining traditional ecological knowledge with contemporary research methods to develop a strategy for the sustainable use of green turtles. Aware of the need for regional cooperation in turtle conservation, the Yolngu have used satellite telemetry to track the migrations of green turtles and so identify communities with whom they share responsibility for this migratory resource. To achieve this, radio transmitters were attached to 20 female green turtles in 1998 and 1999 as they departed from Djulpan, a major nesting rookery south of Nhulunbuy on the Gove Peninsula. Location ‘fixes’ received via satellite allowed the precise migration routes and locations of their home feeding grounds to be mapped. The Hermon Slade Foundation provided the funds for five transmitters and satellite charges, as well as for the travel costs of researchers.

Contrary to the expectation that these turtles would disperse widely to feeding grounds as far afield as east coastal Queensland, Western Australia or even Indonesia and Papua New Guinea, all turtles remained within the Gulf of Carpentaria with many sharing overlapping feeding grounds. Turtles swam about 50 km per day, travelling to feeding grounds as close as 140 km away in Blue Mud Bay to nearly 720 km away near Bentinck Island in the south-eastern corner of the Gulf. Most of the turtles returned to feeding grounds in Limmen Bight or near the Edward Pellew Islands, in the south-western corner of the Gulf.

These results, coupled with the high fidelity of green turtles to their chosen nesting beach and feeding ground, suggest an optimistic management scenario where the Gulf of Carpentaria green turtle stock may not be threatened by unsustainable harvests of turtles outside Australian waters. Hence, the long-term survival of this stock may be largely determined by the management actions of Australian Indigenous peoples and conservation authorities. Building on these results and their experience in turtle research, the Yolngu are working with other peoples to establish a network of indigenous communities and promote a cooperative management strategy for marine turtles in the region.

Publication

 Kennett, R and Munungurritj, N (2001). Travelling turtles, many peoples, one big history: indigenous management of sea turtles in northern Australia. In: Proceedings of the 21st Annual Symposium on Sea Turtle Conservation and Management, Philadelphia, Pennsylvania, USA (in press).

Video

“Nhaltjan Nguli Miwatj Yolngu Djaka Miuapunuwu: Sea turtle conservation and the Yolngu people of north east Arnhem Land”, produced by the Dhimurru Land Management Aboriginal Corporation.

World Wide Web Reference

http://www.ntu.edu.au/cincrm/projectsresearch/turtle.jpg/
turtlema.html

 

Djawa Yunupingu (Dhimurru Land Management Corporation) and Dr Rod Kennett (Northern Territory University) with the first satellite radio-tagged green turtle to be released in North-eastern Arnhem Land. (Photo: Dhimurru LMAC).

Map of the Gulf of Carpentaria showing the migratory routes of all turtles studied (follow hyperlink to full-size map for detail)