Marine Biology

, Volume 160, Issue 3, pp 519–529 | Cite as

Ecology of loggerhead marine turtles Caretta caretta in a neritic foraging habitat: movements, sex ratios and growth rates

  • ALan F. ReesEmail author
  • Dimitris Margaritoulis
  • Robert Newman
  • Thomas E. Riggall
  • Paul Tsaros
  • Judith A. Zbinden
  • Brendan J. Godley
Original Paper


Much is still to be learned about the spatial ecology of foraging marine turtles, especially for juveniles and adult males which have received comparatively little attention. Additionally, there is a paucity of ecological information on growth rates, size and age at maturity, and sex ratios at different life stages; data vital for successful population modelling. Here, we present results of a long-term (2002–2011) study on the movements, residency, growth and sex ratio of loggerhead turtles (Caretta caretta) in Amvrakikos Gulf (39°0′N 21°0′E), Greece, using satellite telemetry (N = 8) and ongoing capture–mark–recapture (CMR; N = 300 individuals). Individuals encountered at sea ranged from large juvenile to adult (46.2–91.5 cm straight carapace length) and demonstrated growth rates within published norms (<2.7 cm yr−1) that slowed with increasing body size. We revealed that an unexpectedly high proportion of animals were male (>44 % of captures above 65 cm straight carapace length), compared to region-wide female-biased hatchling production, indicating sex-biased survival or possible behavioural drivers for likelihood of capture in the region. Satellite tracking confirmed that some turtles establish discrete, protracted periods of residency spanning more than 1 year, whilst others migrated away from the site. These findings are underlined by CMR results with individual capture histories spanning up to 7 years, and only 18 % of individuals being recaptured.


Tail Length Carapace Length Online Resource Table Marine Turtle Loggerhead Turtle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors would like to thank the editor and two anonymous reviewers whose comments helped improve the final paper. We also thank ETANAM for assistance during 2002 and 2003; this initial study was part-funded by EU LIFE project LIFE99NAT/006475. AFR would like to thank Sonja Baker, Christopher Dean, Kimon Fassoulas, Brian Ground, Andrew Haigh, Andreas Koutsodendris, Jason Margaritoulis, Aliki Panagopoulou, Yiannis Roussopoulos and others for field assistance and Catherine McClellan and Thomas Stringell for discussion and assistance on an earlier draft of the paper. BJG is funded by NERC and the Darwin Initiative. Local support for field teams has been provided by the Kopraina Centre for Environmental Education. The research is carried out with permission from Ministry of Agriculture, and ARCHELON’s activities in the Gulf are supported by the Management Agency of the Gulf and the local coast guard stations at Menidi and Preveza.

Supplementary material

227_2012_2107_MOESM1_ESM.pdf (121 kb)
Supplementary material 1 (PDF 120 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • ALan F. Rees
    • 1
    • 2
    Email author
  • Dimitris Margaritoulis
    • 1
  • Robert Newman
    • 1
  • Thomas E. Riggall
    • 1
  • Paul Tsaros
    • 1
  • Judith A. Zbinden
    • 2
  • Brendan J. Godley
    • 2
  1. 1.ARCHELON, the Sea Turtle Protection Society of GreeceAthensGreece
  2. 2.Marine Turtle Research Group, Centre for Ecology and ConservationUniversity of ExeterPenryn, CornwallUK

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