Skip to main content

Sex ratio estimations of loggerhead sea turtle hatchlings by histological examination and nest temperatures at Fethiye beach, Turkey

Naturwissenschaften volume 93, pages 338–343 (2006)Cite this article

Abstract

Hatchling sex ratios in the loggerhead turtle (Caretta caretta) were estimated by placing electronic temperature recorders in 21 nests at Fethiye beach during 2000–2002. Over the seasons, the mean temperature in the middle third of the incubation period ranged from 26.7 to 32.1°C, and incubation periods ranged from 49 to 67 days. Based on the mean temperatures during the middle third of the incubation period, and on histologically sexed dead hatchlings, the sex ratios of hatchlings at Fethiye beach were roughly equal, i.e. 60–65% of the hatchlings were females. This contrasts with the highly female-skewed sex ratios in loggerhead turtles elsewhere; Fethiye has a relatively high proportion of male hatchlings. For endangered sea turtles, the knowledge of hatchling sex ratios at different beaches, coupled with appropriate conservation measures, can make an important contribution to their survival.

This is a preview of subscription content, access via your institution.

Access options

Buy single article

Instant access to the full article PDF.

43,34 €

Price includes VAT (Finland)
Tax calculation will be finalised during checkout.

Fig. 1
Fig. 2

References

  • Baptistotte C, Scalfoni JT, Mrosovsky N (1999) Male-producing thermal ecology of a southern loggerhead nesting beach in Brazil: implications for conservation. Anim Conserv 2:9–13

    Article  Google Scholar 

  • Godfrey MH, Barreto R, Mrosovsky N (1997) Metabolically-generated heat of developing eggs and its potential effect on sex ratio of sea turtle hatchlings. J Herpetol 31:616–619

    Article  Google Scholar 

  • Godley BJ, Broderick AC, Mrosovsky N (2001) Estimating hatchling sex ratios of loggerhead turtles in Cyprus from incubation durations. Mar Ecol Prog Ser 210:195–201

    Article  Google Scholar 

  • Hanson J, Wibbels T, Martin RE (1998) Predicted female bias in hatchling sex ratios of loggerhead sea turtles from a Florida nesting beach. Can J Zool 76:1850–1861

    Article  Google Scholar 

  • Hays GC, Ashworth JS, Barnsley MJ, Broderick AC, Emery DR, Godley BJ, Henwood A, Jones EL (2001) The importance of sand albedo for the thermal conditions on sea turtle nesting beaches. Oikos 93:87–95

    Article  Google Scholar 

  • Houghton JDR, Hays GC (2001) Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings. Naturwissenschaften 88:133–136

    PubMed  Article  CAS  Google Scholar 

  • Kaska Y (2000) Predation pattern of loggerhead and green turtle nests in the Eastern Mediterranean and its possible effect on sex ratio. Isr J Zool 46:343–349

    Article  Google Scholar 

  • Kaska Y, Downie JR (1999) Embryological development of sea turtles (Chelonia mydas, Caretta caretta) in the Mediterranean. Zool Middle East 19:55–69

    Google Scholar 

  • Kaska Y, Downie JR, Tippett R, Furness R (1998) Natural temperature regimes for loggerhead and green turtle nests in the eastern Mediterranean. Can J Zool 76:723–729

    Article  Google Scholar 

  • Marcovaldi MA, Godfrey MH, Mrosovsky N (1997) Estimating sex ratios of loggerhead turtles in Brazil from pivotal incubation durations. Can J Zool 75:755–770

    Article  Google Scholar 

  • Matsuzawa Y, Sato K, Sakamoto W, Bjorndal KA (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. Mar Biol 140:639–646

    Article  Google Scholar 

  • Mrosovsky N (1994) Sex ratios of sea turtles. J Exp Zool 270:16–27

    Article  Google Scholar 

  • Mrosovsky N, Pieau C (1991) Transitional range of temperature, pivotal temperatures and thermosensitive stages for sex determination in reptiles. Amphib-Reptil 12:169–179

    Article  Google Scholar 

  • Mrosovsky N, Kamel S, Rees AF, Margaritoulis D (2002) Pivotal temperature for loggerhead turtles (Caretta caretta) from Kyparissia Bay, Greece. Can J Zool 80:2118–2124

    Article  Google Scholar 

  • Öz M, Erdogan A, Kaska Y, Dusen S, Aslan A, Sert H, Yavuz M, Tunc MR (2004) Nest temperatures and sex-ratio estimates of loggerhead turtles at Patara beach on the southwestern coast of Turkey. Can J Zool 82:94–101

    Article  Google Scholar 

  • Türkozan O, Baran I (1996) Research on the loggerhead turtle, Caretta caretta, of Fethiye beach. Turk J Zoolog 20:183–188

    Google Scholar 

  • Wibbels T (2003) Critical approaches to sex determination in sea turtles. In: Lutz PL, Musick JA, Wyneken J (eds) The biology of sea turtles. CRC, Boca Raton, pp 103–134

    Google Scholar 

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

    Google Scholar 

Download references

Acknowledgements

We thank all the volunteers from Pamukkale, Dokuz Eylul, Adnan Menderes and Vienna Universities for their help during the fieldwork. Y. Kaska thanks the Pamukkale University Research Fund for partly financing the project (2000-FEF01-BAD001). M. Stachowitsch wishes to thank his assistant, C. Fellhofer and acknowledges support from the ‘Society of the Friends of Schönbrunn 200’ and ‘Gulet Touropa Touristik’. We are grateful to Tony Holmes for English corrections on an earlier manuscript version. The manuscript has improved considerably as a result of comments received from anonymous referees.

Author information

Affiliations

  1. Pamukkale Üniversitesi, Fen Edebiyat Fakültesi, Biyoloji Bölümü Denizli, Turkey

    Yakup Kaska & Eyüp Başkale

  2. Dokuz Eylül Üniversitesi, Buca Eðitim Fakültesi, Biyoloji Bölümü, 35150, Buca-Izmir, Turkey

    İbrahim Baran

  3. Adnan Menderes Üniversitesi, Fen Edebiyat Fakültesi, Biyoloji Bölümü, 09010, Aydin, Turkey

    Oğuz Türkozan

  4. Faculty of Life Sciences, Department of Marine Biology, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria

    Michael Stachowitsch

  5. Dokuz Eylül University, Fauna and Flora Research and Aplication Center, Buca-Izmir, 35150, Turkey

    Çetin Ilgaz

  6. Adnan Menderes Üniversitesi, Egitim Fakültesi, Ilkögretim Bölümü, Aydin, 09010, Turkey

    Adem Özdemir

Authors
  1. Yakup Kaska
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Çetin Ilgaz
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Adem Özdemir
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Eyüp Başkale
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Oğuz Türkozan
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. İbrahim Baran
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Michael Stachowitsch
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Yakup Kaska.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Kaska, Y., Ilgaz, Ç., Özdemir, A. et al. Sex ratio estimations of loggerhead sea turtle hatchlings by histological examination and nest temperatures at Fethiye beach, Turkey. Naturwissenschaften 93, 338–343 (2006). https://doi.org/10.1007/s00114-006-0110-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00114-006-0110-5

Keywords

  • Nest Season
  • Nest Temperature
  • Loggerhead Turtle
  • Entire Incubation Period
  • Sand Temperature