Advertisement

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. Rees
  • Dimitris Margaritoulis
  • Robert Newman
  • Thomas E. Riggall
  • Paul Tsaros
  • Judith A. Zbinden
  • Brendan J. Godley
Original Paper

Abstract

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.

Keywords

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.

Notes

Acknowledgments

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)

References

  1. Abesamis RA, Russ GR (2005) Density-dependent spillover from a marine reserve: long-term evidence. Ecol Appl 15:1798–1812CrossRefGoogle Scholar
  2. Andrews RD, Pitman RL, Balance LT (2008) Satellite tracking reveals distinct movement patterns for Type B and Type C killer whales in the southern Ross sea Antarctica. Polar Biol 31:1461–1468CrossRefGoogle Scholar
  3. Avens L, Braun-McNeill J, Epperly S, Lohmann KJ (2003) Site fidelity and homing behavior in juvenile loggerhead sea turtles (Caretta caretta). Mar Biol 143:211–220CrossRefGoogle Scholar
  4. Baird RW, Gorgone AM, McSweeney DJ, Webster DL, Salden DR, Deakos MH, Ligon AD, Schorr GS, Barlow J, Mahaffy SD (2008) False killer whales (Pseudorca crassidens) around the main Hawaiian Islands: long-term site fidelity, inter-island movements, and association patterns. Mar Mamm Sci 24:591–612CrossRefGoogle Scholar
  5. Balazs GH (1999) Factors to consider in the tagging of sea turtles. In: Eckert KL, Bjorndal KA, Abreu-Grobois FA, Donnelly M (eds) Research and management techniques for the conservation of sea turtles. IUCN/SSC Mar Turtle Spec Group Publ No. 4. IUCN/SSC Marine Turtle Specialist Group, Washington, DC, pp 101–109Google Scholar
  6. Balazs GH, Miya RK, Beavers SC (1996) Procedures to attach a satellite transmitter to the carapace of an adult green turtle, Chelonia mydas. In: Keinath JA, Barnard DE, Musick JA, Bell BA (eds) Proceedings of the fifteenth annual workshop on sea turtle biology and conservation. NOAA Tech Memo NMFS-SEFSC-387, pp 21–26Google Scholar
  7. Bearzi G, Agazzi S, Bonizzoni S, Costa M, Azzellino A (2008) Dolphins in a bottle: abundance, residency patterns and conservation of bottlenose dolphins Tursiops truncatus in the semi-closed eutrophic Amvrakikos Gulf, Greece. Aquat Conserv Mar Freshw Ecosyst 18:130–146CrossRefGoogle Scholar
  8. Bjorndal KA, Bolten AB, Martins HR (2000) Somatic growth model of juvenile loggerhead sea turtles Caretta caretta: duration of pelagic stage. Mar Ecol Prog Ser 202:265–272CrossRefGoogle Scholar
  9. Block BA, Teo SLH, Walli A, Boustany A, Stokjesbury MJW, Farwell CJ, Weng KC, Dewar H, Williams TD (2005) Electronic tagging and population structure of Atlantic blue fin tuna. Nature 434:1121–1127CrossRefGoogle Scholar
  10. Block BA, Jonsen ID, Jorgensen SJ, Winship AJ, Shaffer SA, Bograd SJ, Hazen EL, Foley DG, Breed GA, Harrison A-L, Ganong JE, Swithenbank A, Castleton M, Dewar H, Mate BR, Shillinger GL, Schaefer KM, Benson SR, Weise MJ, Henry RW, Costa DP (2011) Tracking apex marine predator movements in a dynamic ocean. Nature 475:86–90CrossRefGoogle Scholar
  11. Bolten AB (1999) Techniques for measuring sea turtles. In: Eckert KL, Bjorndal KA, Abreu-Grobois FA, Donnelly M (eds) Research and management techniques for the conservation of sea turtles. IUCN/SSC Mar Turtle Spec Group Publ No. 4. IUCN/SSC Marine Turtle Specialist Group, Washington, DC, pp 110–114Google Scholar
  12. Bolten AB (2003) Active swimmers—passive drifters: the oceanic juvenile stage of loggerheads in the Atlantic system. In: Bolten AB, Witherington BE (eds) Loggerhead sea turtles. Smithsonian Institution, Washington, pp 63–78Google Scholar
  13. Bolten AB, Bjorndal KA, Martins HR, Dellinger T, Biscoito MJ, Encalada SE, Bowen BW (1998) Transatlantic developmental migrations of loggerhead sea turtles demonstrated by mtDNA sequence analysis. Ecol Appl 8:1–7CrossRefGoogle Scholar
  14. Booth DT, Freeman C (2006) Sand and nest temperatures and an estimate of hatchling sex ratio from the Heron Island green turtle (Chelonia mydas) rookery, Southern Great Barrier Reef. Coral Reefs 25:629–633. doi: 10.1007/s00338-006-0135-4 CrossRefGoogle Scholar
  15. Bowen BW, Kamezaki N, Limpus CJ, Hughes GR, Meylan AB, Avise JC (1994) Global phylogeography of the loggerhead turtle (Caretta caretta) as indicated by mitochondrial DNA haplotypes. Evolution 48:1820–1828CrossRefGoogle Scholar
  16. Bowen BW, Abreu-Grubois FA, Balazs GH, Kamezaki N, Limpus CJ, Ferl RJ (1995) Trans-Pacific migrations of the loggerhead turtle (Caretta caretta) demonstrated with mitochondria1 DNA markers. Proc Natl Acad Sci USA 92:3731–3734CrossRefGoogle Scholar
  17. Bowen BW, Bass AL, Chow S-M, Bostrom M, Bjorndal KA, Bolten AB, Okuyama T, Bolker BM, Epperly S, Lacasella E, Shaver D, Dodd M, Hopkins-Murphy SR, Musick JA, Swingle M, Rankin-Baransky K, Teas W, Witzell WN, Dutton PH (2004) Natal homing in juvenile loggerhead turtles (Caretta caretta). Mol Ecol 13:3797–3808CrossRefGoogle Scholar
  18. Boyle MC, Fitzsimmons NN, Limpus CJ, Kelez S, Velez-Zuazo X, Waycott M (2009) Evidence for transoceanic migrations by loggerhead sea turtles in the southern Pacific Ocean. Proc R Soc Lond B 276:1993–1999CrossRefGoogle Scholar
  19. Broderick AC, Glen F, Godley BJ, Hays GC (2002) Estimating the number of green and loggerhead turtles nesting annually in the Mediterranean. Oryx 36:227–235CrossRefGoogle Scholar
  20. Broderick AC, Glen F, Godley BJ, Hays GC (2003) Variation in reproductive output of marine turtles. J Exp Mar Biol Ecol 288:95–109CrossRefGoogle Scholar
  21. Broderick AC, Coyne MS, Fuller WJ, Glen F, Godley BJ (2007) Fidelity and over-wintering of sea turtles. Proc R Soc Lond B 274:1533–1538CrossRefGoogle Scholar
  22. Cardona L, Revelles M, Carreras C, San Felix M, Gazo M, Aguilar A (2005) Western Mediterranean immature loggerhead turtles: habitat use in spring and summer assessed through satellite tracking and aerial surveys. Mar Biol 147:583–591CrossRefGoogle Scholar
  23. Carreras C, Pascual M, Cardona L, Marco A, Bellido JJ, Castillo JJ, Tomas J, Raga JA, Sanfelix M, Fernandez G, Aguilar A (2011) Living together but remaining apart: Atlantic and Mediterranean loggerhead sea turtles (Caretta caretta) in shared feeding grounds. J Hered 102:666–677CrossRefGoogle Scholar
  24. Casale P, Freggi D, Basso R, Argano R (2005) Size at male maturity, sexing methods and adult sex ratio in loggerhead turtles (Caretta caretta) from Italian waters investigated through tail measurements. Herpetol J 15:145–148Google Scholar
  25. Casale P, Lazar B, Pont S, Tomas J, Zizzo N, Alegre F, Badillo J, Di Summa A, Freggi D et al (2006) Sex ratios of juvenile loggerhead sea turtles Caretta caretta in the Mediterranean Sea. Mar Ecol Prog Ser 324:281–285CrossRefGoogle Scholar
  26. Casale P, Freggi D, Basso R, Vallini C, Argano R (2007) A model of area fidelity, nomadism, and distribution patterns of loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea. Mar Biol 152:1039–1049CrossRefGoogle Scholar
  27. Casale P, Abbate G, Freggi D, Conte N, Olivero M, Argano R (2008) Foraging ecology of loggerhead sea turtles Caretta caretta in the central Mediterranean Sea: evidence for a relaxed life history model. Mar Ecol Prog Ser 372:265–276CrossRefGoogle Scholar
  28. Casale P, Mazaris AD, Freggi D, Vallini C, Argano R (2009) Growth rates and age at adult size of loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea, estimated through capture-mark-recapture records. Sci Mar 73:589–595CrossRefGoogle Scholar
  29. Casale P, Mazaris AD, Freggi D (2011) Estimation of age at maturity of loggerhead sea turtles Caretta caretta in the Mediterranean using length-frequency data. Endanger Species Res 13:123–129CrossRefGoogle Scholar
  30. Casale P, Simone G, Conoscitore C, Conoscitore M, Salvemini P (2012) The Gulf of Manfredonia: a new neritic foraging area for loggerhead sea turtles in the Adriatic Sea. Acta Herpetologica 7:1–12Google Scholar
  31. Chaloupka M (2003) Stochastic simulation modelling of loggerhead population dynamics given exposure to competing mortality risks in the western south Pacific. In: Bolten AB, Witherington BE (eds) Loggerhead sea turtles. Smithsonian Institution, Washington, pp 274–294Google Scholar
  32. Chaloupka M, Limpus CJ (1997) Robust statistical modeling of hawksbill sea turtle growth rates (Southern Great Barrier Reef). Mar Ecol Prog Ser 146:1–8CrossRefGoogle Scholar
  33. Chu CT, Booth DT, Limpus CJ (2008) Estimating the sex ratio of loggerhead turtle hatchlings at Mon Repos rookery (Australia) from nest temperatures. Aust J Zool 56:57–64CrossRefGoogle Scholar
  34. Coll M, Piroddi C, Steenbeek J, Kaschner K, Ben Rais Lasram F et al (2010) The biodiversity of the Mediterranean Sea: estimates, patterns, and threats. PLoS ONE 5:e11842CrossRefGoogle Scholar
  35. Coyne MS, Godley BJ (2005) Satellite Tracking and Analysis Tool (STAT): an integrated system for archiving, analyzing and mapping animal tracking data. Mar Ecol Prog Ser 301:1–7CrossRefGoogle Scholar
  36. Crouse DT, Crowder LB, Caswell H (1987) A stage-based population model for loggerhead sea turtles and implications for conservation. Ecology 68:1412–1423CrossRefGoogle Scholar
  37. Croxall JP, Silk JRD, Phillips RA, Afanasyev V, Briggs DR (2005) Global circumnavigations: tracking year-round ranges of nonbreeding albatrosses. Science 307:249–250CrossRefGoogle Scholar
  38. Donlan CJ, Wingfield DK, Crowder LB, Wilcox C (2010) Using expert opinion surveys to rank threats to endangered species: a case study with sea turtles. Conserv Biol 24:1586–1595CrossRefGoogle Scholar
  39. Eckert SA, Dolar LL, Kooyman GL, Perrin W, Rahman RA (2002) Movements of whale sharks (Rhincodon typus) in south-east Asian waters as determined by satellite telemetry. J Zool 257:111–115CrossRefGoogle Scholar
  40. Ehrhart LM, Ogren LH (1999) Studies in foraging habitats: capturing and handling turtles. In: Eckert KL, Bjorndal KA, Abreu-Grobois FA, Donnelly M (eds) Research and management techniques for the conservation of sea turtles. IUCN/SSC Mar Turtle Spec Group Publ No. 4. IUCN/SSC Marine Turtle Specialist Group, Washington, DC, pp 61–64Google Scholar
  41. Encalada SE, Bjorndal KA, Bolten AB, Zurita JC, Schroeder B, Possardt E, Sears CJ, Bowen BW (1998) Population structure of loggerhead turtle (Caretta caretta) nesting colonies in the Atlantic and Mediterranean as inferred from mitochondrial DNA control region sequences. Mar Biol 130:567–575CrossRefGoogle Scholar
  42. Ferentinos G, Papatheodorou G, Geraga M, Iatrou M, Fakiris E, Christodoulou D, Dimitriou E, Koutsikopoulos C (2010) Fjord waters circulation patterns and dysoxic/anoxic conditions in a Mediterranean semi-enclosed embayment in the Amvrakikos Gulf, Greece. Estuar Coast Shelf Sci 88:473–481CrossRefGoogle Scholar
  43. Fuentes MMPB, Hamann M, Limpus CJ (2010) Past, current and future thermal profiles for green turtle nesting grounds: implications from climate change. J Exp Mar Biol Ecol 383:55–64CrossRefGoogle Scholar
  44. Giorgi F, Lionello P (2008) Climate change projections for the Mediterranean region. Glob Planet Change 63:90–104CrossRefGoogle Scholar
  45. Godley BJ, Lima EHSM, Åkesson S, Broderick AC, Glen F, Godfrey MH, Luschi P, Hays GC (2003) Movement patterns of green turtles in Brazilian coastal waters described by satellite tracking and flipper tagging. Mar Ecol Prog Ser 253:279–288CrossRefGoogle Scholar
  46. Hamann M, Godfrey MH, Seminoff JA, Arthur K, Barata PCR, Bjorndal KA, Bolten AB, Broderick AC, Campbell LM, Carreras C, Casale P, Chaloupka M, Chan SKF, Coyne MS, Crowder LB, Diez CE, Dutton PH, Epperly SP, FitzSimmons NN, Formia A, Girondot M, Hays GC, Cheng IS, Kaska Y, Lewison R, Mortimer JA, Nichols WJ, Reina RD, Shanker K, Spotila JR, Tomas J, Wallace BP, Work TM, Zbinden J, Godley BJ (2010) Global research priorities for sea turtles: informing management and conservation in the twenty first century. Endanger Species Res 11:245–269CrossRefGoogle Scholar
  47. Hanson J, Wibbels T, Martin RE (1998) Predicted female bias in sex ratios of hatchling loggerhead seas turtles from a Florida nesting beach. Can J Zool 76:1850–1861CrossRefGoogle Scholar
  48. Hatase H, Takai N, Matsuzawa Y, Sakamoto W, Omuta K, Goto K, Arai N, Fujiwara T (2002) Size-related differences in feeding habitat use of adult female loggerhead turtles Caretta caretta around Japan determined by stable isotope analyses and satellite telemetry. Mar Ecol Prog Ser 233:273–281CrossRefGoogle Scholar
  49. Hawkes LA, Broderick AC, Coyne MS, Godfrey MH, Lopez-Jurado LF, Lopez-Suarez P, Merino SE, Varo-Cruz N, Godley BJ (2006) Phenotypically linked dichotomy in sea turtle foraging requires multiple conservation approaches. Curr Biol 16:990–995CrossRefGoogle Scholar
  50. Hawkes LA, Broderick AC, Godfrey MH, Godley BJ (2009) Climate change and marine turtles. Endanger Species Res 7:137–154CrossRefGoogle Scholar
  51. Hawkes LA, Witt MJ, Broderick AC, Coker JW, Coyne MS, Dodd M, Frick MG, Godfrey MH, Griffin DB, Murphy SR, Murphy TM, Williams KL, Godley BJ (2011) Home on the range: spatial ecology of loggerhead turtles in Atlantic waters of the USA. Divers Distrib 17:624–640CrossRefGoogle Scholar
  52. Hays GC, Fosssette S, Katselidis KA, Schofield G, Gravenor MB (2010) Breeding periodicity for male sea turtles, operational sex ratios, and implications in the face of climate change. Conserv Biol 24:1636–1643CrossRefGoogle Scholar
  53. Heithaus MR, Wirsing AJ, Dill LM, Heithaus LI (2007) Long-term movements of tiger sharks satellite-tagged in Shark Bay, Western Australia. Mar Biol 151:1455–1461CrossRefGoogle Scholar
  54. Heppell SS, Crowder LB, Menzel T (1999) Life table analysis of long-lived marine species with implications for management. Am Fish Soc Symp 23:137–148Google Scholar
  55. Holdsworth JC, Sippel TJ, Block BA (2009) Near real time satellite tracking of striped marlin (Kajikia audax) movements in the Pacific Ocean. Mar Biol 156:505–514CrossRefGoogle Scholar
  56. Hughes GR (1974) The sea turtles of southeast Africa. II. Investigational report, vol 36. Oceanographic Research Institute, DurbanGoogle Scholar
  57. Ishihara T, Kamezaki N (2011) Size at maturity and tail elongation of loggerhead turtles (Caretta caretta) in the North Pacific. Chelonian Conserv Biol 10:281–287CrossRefGoogle Scholar
  58. Kapsimalis V, Pavlakis P, Poulos SE, Alexandri S, Tziavos C, Sioulas A, Filippas D, Lyskousis V (2005) Internal structure and evolution of the Late Quaternary sequence in a shallow embayment: the Amvrakikos Gulf, NW Greece. Mar Geol 222–223:399–418CrossRefGoogle Scholar
  59. Kountoura K, Zacharias I (2011) Temporal and spatial distribution of hypoxic/seasonal anoxic zone in Amvrakikos Gulf, Western Greece. Estuar Coast Shelf Sci 94:123–128CrossRefGoogle Scholar
  60. Laurent L, Casale P, Bradai MN, Godley BJ, Gerosa G, Broderick AC, Schroth W, Schierwater B, Levy AM, Freggi D, Abd El-Mawla EM, Hadoud DA, Gomati HE, Domingo M, Hadjichristophorou M, Kornaraky L, Demirayak F, Gautier C (1998) Molecular resolution of marine turtle stock composition in fishery bycatch: a case study in the Mediterranean. Mol Ecol 7:1529–1542CrossRefGoogle Scholar
  61. Lazar B, Lackovic G, Casale P, Freggi D, Tvrtkovic N (2008) Histological validation of gonad gross morphology to sex juvenile loggerhead sea turtles (Caretta caretta). Herpetol J 18:137–140Google Scholar
  62. Limpus CJ, Limpus DJ (2001) The loggerhead turtle, Caretta caretta, in Queensland: breeding migrations and fidelity to a warm temperate feeding area. Chelonian Conserv Biol 4:142–153Google Scholar
  63. Limpus CJ, Limpus DJ (2003) Biology of the loggerhead turtle in western South Pacific Ocean foraging areas. In: Bolten AB, Witherington BE (eds) Loggerhead sea turtles. Smithsonian Institution, Washington, DC, pp 93–113Google Scholar
  64. Lutcavage ME, Plotkin P, Witherington B, Lutz PL (1997) Human impacts on sea turtle survival. In: Lutz PL, Musick JA (eds) The biology of sea turtles. CRC Press, Boca Raton, pp 387–409Google Scholar
  65. Lynnes A, Reid K, Croxall J, Trathan P (2002) Conflict or co-existence? Foraging distribution and competition for prey between Adelie and chinstrap penguins. Mar Biol 141:1165–1174CrossRefGoogle Scholar
  66. Marcovaldi MA, Godfrey MH, Mrosovsky N (1997) Estimating sex ratios of loggerhead turtles in Brazil from pivotal incubation durations. Can J Zool 75:755–770CrossRefGoogle Scholar
  67. Margaritoulis D, Rees AF (2011) Loggerheads nesting at Rethymno prefer the Aegean Sea as their main foraging area. Mar Turt Newsl 131:12–14Google Scholar
  68. Margaritoulis D, Argano R, Baran I, Bentivegna F et al (2003) Loggerhead turtles in the Mediterranean Sea: present knowledge and conservation perspectives. In: Bolten AB, Witherington BE (eds) Loggerhead sea turtles. Smithsonian Institution, Washington, DC, pp 175–198Google Scholar
  69. McClellan CM, Read AJ (2007) Complexity and variation in loggerhead sea turtle life history. Biol Lett 3:592–594CrossRefGoogle Scholar
  70. Mrosovsky N, Dutton PH, Whitmore P (1984) Sex ratios of two species of sea turtle nesting in Suriname. Can J Zool 62:2227–2239CrossRefGoogle Scholar
  71. Nicholls RJ, Hoozemans FMJ, Marchand M (1999) Increasing flood risk and wetland losses due to global sea-level rise: regional and global analyses. Glob Environ Change 9:S69–S87CrossRefGoogle Scholar
  72. Piovano S, Clusa M, Carreras C, Giacoma C, Pascual M, Cardona L (2011) Different growth rates between loggerhead sea turtles (Caretta caretta) of Mediterranean and Atlantic origin in the Mediterranean Sea. Mar Biol 158:2577–2587CrossRefGoogle Scholar
  73. Rees AF, Al Saady S, Broderick AC, Coyne MS, Papathanasopoulou N, Godley BJ (2010) Behavioural polymorphism in one of the world’s largest populations of loggerhead sea turtles Caretta caretta. Mar Ecol Prog Ser 418:201–212CrossRefGoogle Scholar
  74. Revelles M, Cardona L, Aguilar A, San Felix M, Fernandez G (2007) Habitat use by immature loggerhead sea turtles in the Algerian Basin (western Mediterranean): swimming behaviour, seasonality and dispersal pattern. Mar Biol 151:1501–1515CrossRefGoogle Scholar
  75. Sasso CR, Braun-McNeill J, Avens L, Epperly SP (2006) Effects of transients on estimating survival and population growth in juvenile loggerhead turtles. Mar Ecol Prog Ser 324:287–292CrossRefGoogle Scholar
  76. Schofield G, Lilley MKS, Bishop CM, Brown P, Katselidis KA, Dimopoulos P, Pantis JD, Hays GC (2009) Conservation hotspots: implications of intense spatial area use by breeding male and female loggerheads at the Mediterranean’s largest rookery. Endanger Species Res 10:191–202CrossRefGoogle Scholar
  77. Schofield G, Hobson VJ, Fossette S, Lilley MKS, Katselidis KA, Hays GC (2010) Fidelity to foraging sites, consistency of migration routes and habitat modulation of home range by sea turtles. Divers Distrib 16:840–853CrossRefGoogle Scholar
  78. Scott MD, Wells RS, Irvine AB (1990) A long-term study of bottlenose dolphins on the West North Atlantic. In: Leatherwood S, Reevers RR (eds) The bottlenose dolphin. Academic Press, San Diego, pp 235–244Google Scholar
  79. Seminoff JA, Resendiz A, Resendiz B, Nichols WJ (2004) Occurrence of loggerhead sea turtles (Caretta caretta) in the Gulf of California, Mexico: evidence of life-history variation in the Pacific Ocean. Herpetol Rev 35:24–27Google Scholar
  80. Steckenreuter A, Pilcher N, Krüger B, Ben J (2010) Male-biased primary sex ratio of leatherback turtles (Dermochelys coriacea) at the Huon Coast, Papua New Guinea. Chelonian Conserv Biol 9:123–128CrossRefGoogle Scholar
  81. Tiwari M, Bjorndal KA (2000) Variation in morphology and reproduction in loggerheads, Caretta caretta, nesting in the United States, Brazil, and Greece. Herpetologica 56:342–356Google Scholar
  82. Tomas J, Aznar FJ, Raga JA (2001) Feeding ecology of the loggerhead turtle Caretta caretta in the western Mediterranean. J Zool Lond 255:525–532CrossRefGoogle Scholar
  83. Troëng S, Rankin E (2005) Long-term conservation efforts contribute to positive green turtle Chelonia mydas nesting trend at Tortuguero, Costa Rica. Biol Conserv 121:111–116CrossRefGoogle Scholar
  84. Troëng S, Dutton PH, Evans D (2005a) Migration of hawksbill turtles Eretmochelys imbricata from Tortuguero, Costa Rica. Ecography 28:394–402CrossRefGoogle Scholar
  85. Troëng S, Evans DR, Harrison E, Lagueux CJ (2005b) Migration of green turtles Chelonia mydas from Tortuguero, Costa Rica. Mar Biol 148:435–447CrossRefGoogle Scholar
  86. van Dam RP (1999) Measuring sea turtle growth. In: Eckert KL, Bjorndal KA, Abreu-Grobois FA, Donnelly M (eds) Research and management techniques for the conservation of sea turtles. IUCN/SSC Mar Turtle Spec Group Publ No. 4. IUCN/SSC Marine Turtle Specialist Group, Washington, DC, pp 149–151Google Scholar
  87. White M, Boura L, Venizelos L (2010) An overview of MEDASSET’s role in sea turtle research and conservation in Albania. Testudo 7:43–54Google Scholar
  88. Wibbels T (2003) Critical approaches to sex determination in sea turtles. In: Lutz PL, Musick JA, Wyneken J (eds) The biology of sea turtles, vol 2., CRC PressBoca Raton, FL, pp 103–134Google Scholar
  89. Wibbels T, Hillis-Starr ZM, Phillips B (1999) Female-biased sex ratios of hatchling hawksbill sea turtles from a Caribbean nesting beach. J Herpetol 33:142–144CrossRefGoogle Scholar
  90. Witt MJ, Akesson S, Broderick AC, Coyne MS, Ellick J, Formia A, Hays GC, Luschi P, Stroud S, Godley BJ (2010a) Assessing accuracy and utility of satellite-tracking data using Argos-linked Fastloc-GPS. Anim Behav 80:571–581CrossRefGoogle Scholar
  91. Witt MJ, Hawkes LA, Godfrey MH, Godley BJ, Broderick AC (2010b) Predicting the impacts of climate change on a globally distributed species: the case of the loggerhead turtle. J Exp Biol 213:901–911CrossRefGoogle Scholar
  92. Worton BJ (1989) Kernel methods for estimating the utilization distribution in home-range studies. Ecology 70:164–168CrossRefGoogle Scholar
  93. Zbinden JA, Bearhop S, Bradshaw P, Gill B, Margaritoulis D, Newton J, Godley BJ (2011) Migratory dichotomy and associated phenotypic variation in marine turtles revealed by satellite tracking and stable isotope analysis. Mar Ecol Prog Ser 421:291–302CrossRefGoogle Scholar
  94. Zogaris S, Papandropoulos D, Alivizatos CH, Rigas Y, Hatzirvasanis V, Kardakari N (2003) Threatened birds of the Amvrakikos. KOAN press, Athens, p 108. [In Greek and with extended English summary and check-lists]Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • ALan F. Rees
    • 1
    • 2
  • 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

Personalised recommendations