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Sabrina Trocini DVM, MVS

Doctor of Philosophy Thesis
Conservation of the endangered loggerhead turtle (Caretta caretta): Health assessment and hatching success of Western Australian populations

Supervisors

  • Prof. Ian Robertson
  • Dr Kris Warren
  • Dr Amanda O‘Hara
  • Prof. Stuart Bradley

Most of the existing sea turtle populations worldwide are in decline, and loggerhead turtles (Caretta caretta), in particular, are listed as endangered. The loggerhead nesting population in Western Australia is estimated to consist of about 1500 females, and is consequently the largest nesting population in Australia and one of the largest in the Indian Ocean (Baldwin et al. 2003).Dr Trocini’s research investigated hatching success and health, two critical aspects for loggerhead turtle conservation and management, on two important loggerhead nesting sites in Western Australia: Dirk Hartog Island and the smaller mainland nesting site in the Cape Range National Park, Bungelup Beach.

In this study, morphological and reproductive measurements were collected during two nesting seasons, between 2006 and 2008. At the same time several biotic and abiotic factors have been assessed in relation to embryonic and hatchling mortality. Additionally, Dr Trocini recorded and classified all the deformities encountered, providing an important database to possibly identify environmental or physiological factors that may influence this phenomenon. These data are fundamental to understand the importance of a nesting beach and its suitability as an incubation system and to assist in assessing the general health of the nesting population. On the mainland nesting site the main limiting factor is predation. This study consequently aimed to not only quantify levels of predation, but also monitor temporal and spatial dynamics of introduced and native nest predators at Bungelup Beach.

Dr Trocini’s research is also the first epidemiological research undertaken to determine the health of sea turtle populations in Western Australia. Health monitoring of the nesting populations enabled the determination of baseline blood health indices, toxin levels in blood, the identification of blood parasites, and other potential causes of mortality and morbidity in Western Australian loggerhead turtles.

This project has an inter-disciplinary approach; it encompasses the disciplines of veterinary epidemiology, conservation medicine and ecology to investigate questions about sea turtle conservation that cannot be addressed by any of these disciplines alone. Several collaborations have been established to further expand on aspects that will not be included in this PhD project. It is anticipated that the research findings will contribute meaningfully to the scientific literature and enhance current knowledge on loggerhead sea turtle reproduction and health; and will also provide important data upon which informed management decisions and conservation policy can be based.

Once complete, this thesis will available in Murdoch University's Digital Thesis collection - http://wwwlib.murdoch.edu.au/adt/

Baldwin R, Hughes GR, Prince RIT, 2003, Loggerhead turtles in the Indian Ocean. In: Bolten AB, Witherington BE (eds) Loggerhead sea turtles. Smithsonian Books, Washington, DC, p 218–232.

Publications

Trocini S, Warren K, O’Hara M, Bradley S and Robertson I, (2008), Health and hatching success of Western Australian loggerhead turtle (Caretta caretta) nesting populations, Discovering Ningaloo – Latest Findings and their Implications for Management: Ningaloo Research Program Progress Report, 22-25.

Conferences

  • May 2009 - 3rd Annual Ningaloo Research Symposium, Exmouth, Australia
    Oral presentation (invited guest speaker): “Loggerhead turtle nest predator dynamics on a mainland nesting beach in Cape Range National Park”
  • March 2009 - 2nd Annual Ningaloo Research Symposium, Perth, Australia
    Oral presentation (best student presentation): “Loggerhead turtle nest predator dynamics on a mainland nesting beach in Cape Range National Park”
  • February 2009 - International Sea turtle symposium, Brisbane, Queensland, Australia
    Oral presentation: Health Assessment of nesting Loggerhead turtles (Caretta caretta) in Western Australia
    Poster: Criminal scene investigation on a Loggerhead turtle nesting beach: who ate the eggs?
  • September 2008 - Wildlife disease association conference-Australasian conference, Kioloa, NSW
    Oral presentation: “The narrow window for biting insects: the epidemiological investigation of a blood-borne pathogen in loggerhead turtles”
  • February 2008 - International Sea turtle symposium, Loreto, Mexico
    Poster: Factors affecting hatching and emergence success at two important Loggerhead turtle (Caretta caretta) nesting beaches in Western Australia
  • May 2008 - 2nd Annual Ningaloo Research Symposium, Perth, Australia
    Poster: “Loggerhead turtle (Caretta caretta) nest predation at Cape Range National Park”
  • September 2007 - Wildlife disease association-Australasian section conference, Dryandra, WA
    Oral presentation: “Health assessment of Loggerhead turtles (Caretta caretta): nesting females and hatchlings”
  • July 2007 - Wildlife disease symposium-Perth Zoo, Australia
    Oral presentation: Health assessment and hatching success of Western Australian Loggerhead turtle (Caretta caretta) nesting populations

Awards

  • March 2009       Best student presentation at the Ningaloo student research day, Perth, Australia (invited to the Ningaloo Research Symposium and travel grant)
  • September 2006    Weston-Fernie Research Fund Award, Murdoch University Veterinary Trust

Collaborators (positions held at December 2010)

  • Dr Peter Spencer, Senior Lecturer, Wildlife Identification Laboratory, School of Biological Sciences and Biotechnology, Murdoch University, Western Australia
  • Dr Leanne Twomey, Specialist Veterinary Clinical Pathologist, Vetpath Laboratory Services, Western Australia
  • Dr Jason Stayt, Clinical Pathologist, Veterinary Clinical Pathology, School of Veterinary and Biomedical Sciences, Murdoch University, Western Australia
  • Dr Susan Perkins, Associate Curator, Microbial Genomics,Division of Invertebrate Zoology, American Museum of Natural History, New York
  • Dr Michael Heithaus, Director, School of Environment, Arts and Society, Florida International University, Florida
  • Dr Nicole Mitchell, Assistant Professor, School of Animal Biology, The University of Western Australia
  • Dr Peter Taylor, Chemistry Centre, Western Australia
  • Dr Michael Krutzen, Senior Lecturer, Anthropological Institute and Museum, University of Zürich, Switzerland

Acknowledgements

This research was undertaken with financial support provided by the Hermon Slade Foundation, BHP-Billiton, the Western Australian Department of Environment and Conservation, Murdoch University and the Murdoch University Veterinary Trust. I would also like to sincerely thank all my volunteers who helped me during the long hours of fieldwork.

Photos provided by Sabrina Trocini

Department of Environment and Conservationbhp billitonThe Hermon Slade Foundation