Australian Journal of Zoology Australian Journal of Zoology Society
Evolutionary, molecular and comparative zoology
RESEARCH ARTICLE

Estimating the sex ratio of loggerhead turtle hatchlings at Mon Repos rookery (Australia) from nest temperatures

Cuong The Chu A , David T. Booth A C and Colin J. Limpus B
+ Author Affiliations
- Author Affiliations

A School of Integrative Biology, The University of Queensland, Qld 4072, Australia.

B Environmental Protect Agency, Queensland Parks and Wildlife Service, PO Box 155, Brisbane, Qld 4002, Australia.

C Corresponding author. Email: d.booth@uq.edu.au

Australian Journal of Zoology 56(1) 57-64 https://doi.org/10.1071/ZO08004
Submitted: 8 January 2008  Accepted: 1 July 2008   Published: 14 August 2008

Abstract

Sand temperatures and loggerhead turtle nest temperatures (Caretta caretta) at Mon Repos rookery (Australia) were monitored over the 2005–06 and 2006–07 nesting seasons and hatchling sex ratios of clutches were estimated using the Constant Temperature Equivalent method. Nest temperatures were positively correlated with the sand temperature and air temperature in both seasons. Both seasons produced a female-biased sex ratio, especially the 2005–06 season, when almost all hatchlings were predicted to be female. Hatch success rate was not affected by nest temperature and averaged 85%, but hot nests from 2005–06 had a reduced emergence success compared with other nests. Daily cyclic temperature fluctuations of 0.5–1.5°C were a feature of nests, with a tendency for greater daily amplitude in the 2005–06 season when the average daily temperature was hotter. These daily temperature fluctuations increased the constant temperature equivalent temperature by 0.1–0.5°C above mean nest temperature during the sex-determining period and resulted in an increased female bias in the estimated hatchling sex ratio.


Acknowledgements

This work was approved by a University of Queensland Animal ethics committee, certificate number: SIB/433/05/URG. We thank three anonymous reviewers for their helpful comments on a previous version of this manuscript.


References

Australian Bureau of Meteorology (2007). http://www.bom.gov.au/climate/averages/tables/cw_039128.shtml. [Accessed 20 March 2007].

Booth, D. T. , and Astill, K. (2001). Temperature variation within and between nests of the green sea turtle, Chelonia mydas (Chelonia: Cheloniidae) on Heron Island, Great Barrier Reef. Australian Journal of Zoology 49, 71–84.
CrossRef |

Booth, D. T. , and Freeman, C. (2006). Sand and nest temperatures and an estimate of hatchling sex ratio from Heron Island green turtle (Chelonia mydas) rookery, south Great Barrier Reef. Coral Reefs 25, 629–633.
CrossRef |

Broderick, A. C. , Godley, B. J. , and Hays, G. C. (2001). Metabolic heating and the prediction of sex ratios for green turtles (Chelonia mydas). Physiological and Biochemical Zoology 74, 161–170.
CrossRef | PubMed |

Chaloupka, M. , and Limpus, C. (2001). Trends in the abundance of sea turtles resident in southern Great Barrier Reef waters. Biological Conservation 102, 235–249.
CrossRef |

Chan, E. H. (1989). White spot development, incubation and hatch success of leatherback turtle (Dermochelys coriacea) eggs from Rantau Abung, Malaysia. Copeia 1989, 42–47.
CrossRef |

Dutton P., Broderick D., and FitzSimmons N. (2002). Defining management units: molecular genetics. In ‘Proceedings of the Western Pacific Sea Turtle Cooperative Research & Management Workshop, Honolulu’. (Ed. I. Kinan.) pp. 93–101. Western Pacific Regional Fishery Management Council. I.

Georges, A. , Beggs, K. , Young, J. E. , and Doody, J. S. (2005). Modelling development of reptile embryos under fluctuating temperature regimes. Physiological and Biochemical Zoology 78, 18–30.
CrossRef | PubMed |

Georges, A. , Limpus, C. , and Stoutjesdijk, R. (1994). Hatchling sex in the marine turtle Caretta caretta is determined by proportion of development at a temperature, not daily duration of exposure. Journal of Experimental Zoology 270, 432–444.
CrossRef |

Girondot, M. (1999). Statistical description of temperature-dependent sex determination using maximum likelihood. Evolutionary Ecology Research 1, 479–486.


Godfrey, M. , and Mrosovsky, N. (2006). Pivotal temperature for green sea turtles, Chelonia mydas, nesting in Suriname. Herpetological Journal 16, 55–61.


Godfrey, M. H. , D’Amato, A. F. , Marcovaldi, M. A. , and Mrosovsky, N. (1999). Pivotal temperature and predicted sex ratios for hatchling hawksbill turtles from Brazil. Canadian Journal of Zoology 77, 1465–1473.
CrossRef |

Godley, B. J. , Broderick, A. C. , Downie, J.R. , Glen, F. , Houghton, J. D. , Kirkwood, I. , Reece, S. , and Hays, G. C. (2001a). Thermal conditions in nests of loggerhead turtles: further evidence suggesting female skewed sex ratios of hatchling production in the Mediterranean. Journal of Experimental Marine Biology and Ecology 263, 45–63.
CrossRef |

Godley, B. J. , Broderick, A. C. , and Mrosovsky, N. (2001b). Estimating hatchling sex ratios of loggerhead turtles in Cyprus from incubation durations. Marine Ecology Progress Series 210, 195–201.
CrossRef |

Gyuris, E. , and Limpus, C. J. (1988). The loggerhead turtle Caretta caretta in Queensland: population breeding structure. Australian Wildlife Research 15, 197–209.
CrossRef |

Hanson, J. , Wibbels, T. , and Martin, R. E. (1998). Predicted female bias in sex ratios of hatchling loggerhead sea turtles from a Florida nesting beach. Canadian Journal of Zoology 76, 1850–1861.
CrossRef |

Hawkes, L. A. , Broderick, A. C. , Godfrey, B. J. , and Godley, B. J. (2007). Investigating the potential impacts of climate change on a marine turtle population. Global Change Biology 13, 923–932.
CrossRef |

Hopkins-Murphy S. R., Owens D. W., and Murphy T. M. (2003). Ecology of immature loggerheads on foraging ground and adults in internesting habitat in the eastern United States. In ‘Loggerhead Sea Turtles’. (Eds A. B. Bolten and B. E. Witherington.) pp. 79–92. (Smithsonian Books: Washington, DC.)

Johnson, S. A. , Bjorndal, K. A. , and Bolten, A. B. (1996). Effects of organized turtle watches on loggerhead (Caretta caretta) nesting behavior and hatchling production in Florida. Conservation Biology 10, 570–577.
CrossRef |

Kaska, Y. , Downie, R. , Tippett, R. , and Furness, R. W. (1998). Natural temperature regimes for loggerhead and green turtle nests in the eastern Mediterranean. Canadian Journal of Zoology 76, 723–729.
CrossRef |

Limpus, C. J. (1971). The flatback turtle, Chelonia depressa Garman in southeast Queensland, Australia. Herpetologica 27, 431–436.


Limpus C. J. (1985). study of the loggerhead sea turtle, Caretta caretta, in eastern Australia. Ph.D. Thesis, University of Queensland, Brisbane.

Limpus C. J. (2006). Impacts of climate change on marine turtles: a case study. In ‘UNEP/CMS Secretariat. Migratory Species and Climate Change: Impacts of a Changing Environment on Wild Animals’. pp. 34–39. (UNEP/CMS Convention on Migratory Species & DEFRA: Bonn.)

Limpus C. J., and Limpus D. J. (2003a). Loggerhead turtles in the equatorial and southern Pacific Ocean: a species in decline. In ‘Loggerhead Sea Turtles’. (Eds A. B. Bolten and B. E. Witherington.) pp. 199–209. (Smithsonian Institution Press: Washington, DC.)

Limpus C. J., and Limpus D. J. (2003b). The biology of the loggerhead turtle, Caretta caretta, in southwest Pacific Ocean foraging areas. In ‘Biology and Conservation of Loggerhead Turtles’. (Eds B. Witherington and A. Bolten.) pp. 93–113. (Smithsonian Institution Press: Washington, DC.)

Limpus, C. J. , Baker, V. , and Miller, J. D. (1979). Movement induced mortality of loggerhead eggs. Herpetologica 35, 335–338.


Limpus, C. J. , Couper, P. J. , and Read, M. A. (1994). The loggerhead turtle, Caretta caretta, in Queensland: population structure in a warm temperate feeding area. Memoirs of the Queensland Museum 37, 195–204.


Limpus C., Reed P., and Miller J. (1983). Island and turtles. The influence of choice of nesting beach on sex ratio. In ‘Inaugural Great Barrier Reef Conference’. (Eds J. T. Baker, R. M. Carter and K. P. Stark.) pp. 397–402. (JCU Press: Townsville.)

Limpus C. J., Reed P. C., and Miller J. D. (1985). Temperature dependent sex determination in Queensland sea turtles: intraspecific variation in Caretta caretta. In ‘Biology of Australian Frogs and Reptiles’. (Eds G. Grigg, R. Shine and H. Ehmann.) pp. 343–351. (Surrey Beatty: Sydney.)

Maloney, J. E. , Dariansmith, C. , Takahashi, Y. , and Limpus, C. J. (1990). The environment for development of the embryonic loggerhead turtle (Caretta caretta) in Queensland. Copeia 1990, 378–387.
CrossRef |

Marcovaldi, M. A. , and Laurent, A. (1996). A six season study of marine turtle nesting at Praia do Forte, Bahia, Brazil, with implications for conservation and management. Chelonian Conservation and Biology 2, 55–59.


Marcovaldi, M. A. , Godfrey, M. H. , and Mrosovsky, N. (1997). Estimating sex ratios of loggerhead turtles in Brazil from pivotal incubation durations. Canadian Journal of Zoology 75, 755–770.
CrossRef |

Margaritoulis, D. (2005). Nesting activity and reproductive output of loggerhead sea turtles, Caretta caretta, over 19 seasons (1984–2002) at Laganas Bay, Zakynthos, Greece: the largest rookery in the Mediterranean. Chelonian Conservation and Biology 4, 916–929.


Matsuzawa, Y. , Sato, K. , Sakamoto, W. , and Bjorndal, K. A. (2002). Seasonal fluctuations in sand temperature: effects on the incubation period and mortality of loggerhead sea turtle (Caretta caretta) pre-emergent hatchlings in Minabe, Japan. Marine Biology (Berlin) 140, 639–646.
CrossRef |

Maxwell, J. A. , Motara, M. A. , and Frank, G. H. (1988). A micro-environmental study of the effect of temperature on the sex ratios of the loggerhead turtle, Caretta caretta, from Tongaland, Natal. South African Journal of Zoology 23, 342–350.


Miller J. D. (1985). Embryology of marine turtles. In ‘Biology of the Reptilia. Vol. 14. Development’. (Eds C. Gans, F. Billett and P. Maderson.) pp. 270–328. (John Wiley and Sons: Sydney.)

Miller J. D., and Limpus C. J. (1981). Incubation period and sexual differentiation in the green turtle. In ‘Proceedings of the Melbourne Herpetological Symposium’. (Eds C. B. Banks and A. A. Martin.) pp. 66–73. (Zoological Board of Victoria: Melbourne.)

Mrosovsky, N. (1988). Pivotal temperatures for loggerhead turtles (Caretta caretta) from northern and southern nesting beaches. Canadian Journal of Zoology 66, 661–669.


Mrosovsky, N. (1994). Sex ratios of sea turtles. Journal of Experimental Zoology 270, 16–27.
CrossRef |

Mrosovsky, N. , and Benabib, M. (1990). An assessment of two methods of sexing hatchling sea turtles. Copeia 1990, 589–591.
CrossRef |

Mrosovsky, N. , and Provancha, J. (1992). Sex ratio of hatchling loggerhead sea turtles: data and estimates from a 5-year survey. Canadian Journal of Zoology 70, 530–538.
CrossRef |

Mrosovsky, N. , Baptistotte, C. , and Godfrey, M. H. (1999). Validation of incubation duration as an index of the sex ratio of hatchling sea turtles. Canadian Journal of Zoology 77, 831–835.
CrossRef |

Mrosovsky, N. , Kamel, S. , Rees, A. F. , and Margaritoulis, D. (2002). Pivotal temperature for loggerhead turtles (Caretta caretta) from Kyparissia Bay, Greece. Canadian Journal of Zoology 80, 2118–2124.
CrossRef |

Oz, M. , Erdogan, A. , Kaska, Y. , Dusen, S. , Aslan, A. , Sert, H. , Yavuz, M. , and Tunc, M. R. (2004). Nest temperatures and sex-ratio estimates of loggerhead turtles at Patara beach on the southwestern coast of Turkey. Canadian Journal of Zoology 82, 94–101.
CrossRef |

Parmenter, C. J. (1980). Incubation of green sea turtles (Chelonia mydas) in Torres Strait, Australia: the effect on hatchability. Australian Wildlife Research 7, 487–491.
CrossRef |

Peters, A. , Verhoeven, K. J. F. , and Strijbosch, S. (1994). Hatching and emergence in the Turkish Mediterranean loggerhead turtle, Caretta caretta: natural causes for egg and hatchling failure. Herpetologica 50, 369–373..


Reed P. C. (1980). The sex ratio of hatchling loggerhead turtles – progeny of two nesting adult females. B.Sc.(Honours) Thesis, James Cook University of North Queensland, Townsville.

Rees, A. F. , and Margaritoulis, D. (2004). Beach temperatures, incubator durations and estimated hatchling sex ratio for loggerhead sea turtle nests in southern Kyparissia Bay, Greece. Testudo 6, 000–000.


Spotila, J. R. , Standora, E. A. , Morreale, S. J. , and Ruiz, G. J. (1987). Temperature dependent sex determination in the green turtle (Chelonia mydas): effects on the sex ratio on a natural nesting beach. Herpetologica 43, 74–81.


Standora, E. A. , and Spotila, J. R. (1985). Temperature-dependent sex determination in sea turtles. Copeia 1985, 711–722.
CrossRef |

Walsh K., Hennessy K., Jones R., McInnes K., Page C., Pittock B., Suppiah R., and Whetton P. (2001). Climate change in Queensland under enhanced greenhouse conditions. In ‘Third Annual Report 1999–2000’. (Ed. K. Walsh.) p. 116. (CSIRO Atmospheric Research: Brisbane.)

Wyneken, J. , Burke, T. J. , Salmon, M. , and Pederson, D. K. (1988). Egg failure in natural and relocated sea turtle nests. Journal of Herpetology 22, 88–96.
CrossRef |

Yntema, C. L. , and Mrosovsky, N. (1980). Sexual differentiation in hatchling loggerheads (Caretta caretta) incubated at different controlled temperatures. Herpetologica 36, 33–36.


Yntema, C. L. , and Mrosovsky, N. (1982). Critical periods and pivotal temperatures for sexual differentiation in loggerhead sea turtles. Canadian Journal of Zoology 60, 1012–1016.



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