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Evolutionary, molecular and comparative zoology
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RESEARCH ARTICLE
Contents Vol 55(2)

Effects of sand erosion and current harvest practices on incubation of the flatback sea turtle (Natator depressus)

Andrea U. Koch A C , Michael L. Guinea A and Scott D. Whiting A B
+ Author Affiliations
- Author Affiliations

A Faculty of Education, Health and Science, Charles Darwin University, Darwin, NT 0909, Australia.

B Present address: Marine Biodiversity Group, Department of Natural Resources, Environment and the Arts, PO Box 30, Palmerston, NT 0831, Australia.

C Corresponding author. Email: andrea.koch@cdu.edu.au

Australian Journal of Zoology 55(2) 97-105 https://doi.org/10.1071/ZO06063
Submitted: 21 July 2006  Accepted: 28 February 2007   Published: 28 May 2007

Abstract

A suitable gaseous, hydrous and thermal nest environment is essential for the development of sea turtle embryos. The harvest of partial clutches by indigenous people and changes in nest depth from wind erosion or predation have prompted questions about the impact of clutch size and nest depth on nest success and hatchling output. We investigated the impact of reduced clutch sizes and nest depths on flatback sea turtle (Natator depressus) eggs, using a hatchery on a natural beach and clutch sizes of 10, 30 and 50 eggs, deposited at depths of 25, 35 and 50 cm. Hatchlings were collected on emergence and their size, mass, scalation and locomotor performance were measured. Neither clutch size nor nest depth had a significant effect on hatching success, emergence success or escape success in this study. Smaller clutches had longer incubation durations due to the lower temperatures within the nest, presumably from the lower metabolic heat produced. Hatchlings from deeper nests emerged later in the night than did those from shallower nests. Within the context of this study, changes to clutch size and nest depth appear to have no detrimental effect on the fate of the remaining eggs and the condition and performance of hatchlings.


Acknowledgements

We thank all volunteers for their dedication to the research during the long nights in the field. Thanks to the Baumber family for their support during field trips and providing transport to the study site. Rolf Koch and Cherry Martin provided valuable support and useful comments on this work. Thanks to Keith McGuinness for statistical advice. Ellie Hayward from Charles Darwin University helped prepare the gonad specimens for histological examination. The Northern Territory Bureau of Meteorology provided climatic data and the Northern Territory Herbarium helped identify plant specimens. Experiments were conducted under licenses from the Parks and Wildlife Commission of the Northern Territory (Permit No. 13513) and the Northern Territory University Animal Ethics Committee (Reference No. A02015). This paper benefited from the comments of two anonymous reviewers.


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