Marine Biology

, 163:21 | Cite as

Sea turtle strandings along the Portuguese mainland coast: spatio-temporal occurrence and main threats

  • Lídia Nicolau
  • Marisa Ferreira
  • Jorge Santos
  • Hélder Araújo
  • Marina Sequeira
  • José Vingada
  • Catarina Eira
  • Ana Marçalo
Original paper

Abstract

The present study is a detailed analysis of sea turtle strandings over a 36-year period (1978–2013) along the Portuguese mainland coast. Out of the 806 stranded individuals, the loggerhead turtle Caretta caretta was the most frequent species (57.1 %) followed by the leatherback turtle Dermochelys coriacea (41.8 %), while green turtles Chelonia mydas and Kemp’s Ridley turtles Lepidochelys kempii were rare (respectively 1.0 and 0.1 %). Relative stranding densities of loggerheads showed an increase through time, whereas two leatherback stranding peaks were detected during the years 1994–1998 and 2009–2013. The highest loggerhead stranding density was observed on the southern coast during spring and summer when they are more susceptible to anthropogenic threats. The highest number of leatherback strandings was observed in the North-Central and Central-South western sectors during autumn and in the southern sector during summer, which may relate to seasonal food availability and water temperature considering those stranded animals that were subject to a post-mortem evaluation interaction with fisheries as the primary cause of stranding. Results show for the first time that waters off the Portuguese mainland coast is an important pathway for loggerheads and leatherbacks in the North Atlantic region. The present study serves as important baseline to the development of future sea turtle conservation efforts in the Portuguese mainland coast.

Notes

Acknowledgments

This work was partly funded by the Portuguese Wildlife Society and projects SafeSea EEA-Grants and European Commission’s Life Programme (MarPro NAT/PT/00038). This study was also partly supported by the Portuguese Foundation for Science and Technology (FCT) with grants SFRH/BD/51416/2011 to L. Nicolau, SFRH/BPD/64889/2009 to A. Marçalo and SFRH/BD/30240/2006 to M. Ferreira. C. Eira is supported by MARES (CENTRO-07-ST24-FEDER-002033), QREN, Mais Centro—PORC and EU/ERDF. The authors thank all volunteers, technicians, maritime authority officers and fishermen who contributed to this work. The authors would like to thank all the suggestions made by Dr. Fred Wrona and by two anonymous referees.

References

  1. Alfaro-Shigueto J, Mangel JC, Bernedo F, Dutton PH, Seminoff JA (2011) Small-scale fisheries of Peru: a major sink for marine turtles in the Pacific. J Appl Ecol 48:1432–1440. doi: 10.1111/j.1365-2664.2011.02040.x CrossRefGoogle Scholar
  2. Bellido JJ, Báez JC, Sanchez RF, Castillo JJ, Martín JJ, Mons JL, Real R (2008) Mass strandings of cold stunned loggerhead turtles in the south Iberian Peninsula: ethological implications. Ethol Ecol Evol 4(20):401–405. doi: 10.1080/08927014.2008.9522520 CrossRefGoogle Scholar
  3. Bellido JJ, Castillo JJ, Pinto F, Martín JJ, Mons JL, Báez JC, Real R (2010) Differential geographical trends for loggerhead turtles stranding dead or alive along the Andalusian coast, Southern Spain. J Mar Biol Assoc UK 90(2):225–231. doi: 10.1017/S0025315409990361 CrossRefGoogle Scholar
  4. 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 202:265–272. doi: 10.3354/meps202265 CrossRefGoogle Scholar
  5. 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 Marine Turtle Specialist Group, Washington, pp 110–114Google Scholar
  6. 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 Books, Washington, pp 63–78Google Scholar
  7. Bolten AB, Martins HR, Bjorndal KA, Gordon J (1993) Size distribution of pelagic-stage loggerhead sea turtles (Caretta caretta) in the waters around the Azores and Madeira. Arquipel Life Mar Sci 11A:49–55Google Scholar
  8. Brongersma LD (1972) European atlantic turtles. Zoologsische Verhandelingen 121:1–318Google Scholar
  9. Camiñas JA (2004) Sea turtles of the Mediterranean Sea: population dynamics, sources of mortality and relative importance of fisheries impacts. Expert consultation on interactions between sea turtles and fisheries within an ecosystem context. Food and Agriculture Organization fisheries report 738, Supplement. FAO, RomeGoogle Scholar
  10. Camiñas JA, Valeiras J (2003) Critical areas for loggerhead and leatherback marine turtles in the Western Mediterranean Sea and the Gibraltar Strait Region. In: Proceedings of the first mediterranean conference on marine turtles. Barcelona Convention—Bern Convention—Bonn Convention (CMS): Nicosia, Cyprus, pp 80–85Google Scholar
  11. Carreras C, Pont S, Maffuci F, Pascual M, Barceló A, Bentivegna F, Cardona L, Alegre F, SanFélix M, Fernández G, Aguilar A (2006) Genetic structuring of immature loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea reflects water circulation patterns. Mar Biol 149:1269–1279. doi: 10.1007/s00227-006-0282-8 CrossRefGoogle Scholar
  12. Casale P, Margaritoulis D (2010) Sea turtles in the mediterranean: distribution, threats and conservation priorities. IUCN/SSC Marine Turtle Specialist Group. Gland, Switzerland: IUCN. http://iucn-mtsg.org/publications/med-report/
  13. Casale P, Afronte M, Insacco G, Freggi D, Vallini C, D’Astore PP, Basso R, Paolillo G, Abbate G, Argano R (2010) Sea turtle strandings reveal high anthropogenic mortality in Italian waters. Aquat Conserv 20:611–620. doi: 10.1002/aqc.1133 CrossRefGoogle Scholar
  14. Cejudo D, Varo-Cruz N, Liria A, Castillo JJ, Bellido JJ, López Jurado LF (2006) Transatlantic migration of juvenile loggerhead turtles (Caretta caretta) from the Strait of Gibraltar. Mar Turt Newsl 114:9–11Google Scholar
  15. CMA (2013) Apoyo técnico a la gestión sostenible del medio marino. Informe Regional Junta de Andalucia. http://www.juntadeandalucia.es/medioambiente/portal_web/web/temas_ambientales/biodiversidad/conservacion_biodiversidad/medio_marino/contenidos_relacionados/informe_anual_medio_marino_2013.pdf. Accessed 26 June 2014
  16. Davenport J (1997) Temperature and the life-history strategies of sea turtles. J Ther Biol 22:479–488. doi: 10.1016/S0306-4565(97)00066-1 CrossRefGoogle Scholar
  17. Davenport J, Magill SH, De Verteuille N (1997) The effects of current velocity and temperature upon swimming in juvenile green turtles Chelonia mydas L. Herpetol J 7:143–147Google Scholar
  18. Dell’Amico F, Morinière P (2014) Observations des tortues marines et des poisons-lunes en 2013 (côtes atlantiques françaises). Ann Soc Sci Nat Charente-Maritime 10(5):551–557Google Scholar
  19. Dellinger T (2010) Tartarugas marinhas. In: Loureiro A, Almeida NF, Carretero MA, Paulo OS (eds) Atlas de Anfibios e Repteis de Portugal. ICNF/Esfera do Caos editores, pp 194–209Google Scholar
  20. Doyle TK, Houghton JDR, O’Súilleabháin PF, Hobson VJ, Marnell FD, Davenport J, Hays GC (2008) Leatherback turtles satellite-tagged in European waters. Endanger Species Res 4:23–31. doi: 10.3354/esr00076 CrossRefGoogle Scholar
  21. Duguy R, Moriniere P, Meunier A (2007) Observations des tortues marines en 2006 (Golfe de Gascogne). Ann Soc Sci Nat Charente-Marit 9(7):695–698Google Scholar
  22. Eckert SA (2002) Distribution of juvenile leatherback sea turtle Dermochelys coriacea sightings. Mar Ecol Prog Ser 230:289–293. doi: 10.3354/meps230289 CrossRefGoogle Scholar
  23. Eckert SA (2006) High-use oceanic areas for Atlantic leatherback sea turtles (Dermochelys coriacea) as identified using satellite telemetered location and dive information. Mar Biol 149:1257–1267. doi: 10.1007/s00227-006-0262-z CrossRefGoogle Scholar
  24. Eckert SA, Moore JE, Dunn DC, van Buiten RS, Eckert KL, Halpin P (2008) Modeling loggerhead turtle movement in the Mediterranean: importance of body size and oceanography. Ecol Appl 18:290–308. doi: 10.1890/06-2107.1 CrossRefGoogle Scholar
  25. Epperly SP, Braun J, Chester AJ, Cross FA, Merriner JV, Tester PA, Churchill JH (1996) Beach strandings as an indicator of at-sea mortality of sea turtles. Bull Mar Sci 59:289–297Google Scholar
  26. Erzini K, Gonçalves JMS, Bentes L, Lino PG, Ribeiro J, Moutopoulos DK, Stergiou KI (2010) Competition between static gear of the small-scale fisheries in Algarve waters (southern Portugal). Med Mar Sci 11:225–243. doi: 10.12681/nms.74 Google Scholar
  27. Fiúza AF (1983) Upwelling patterns off Portugal. In: Thiede J, Suess E (eds) Coastal upwelling. Plenum Publishers, Berlin, pp 85–87CrossRefGoogle Scholar
  28. Fleming NEC, Harrod C, Houghton JDR (2013) Identifying potentially harmful jellyfish blooms using shoreline surveys. Aquacult Environ Interact 4:263–272. doi: 10.3354/aei00086 CrossRefGoogle Scholar
  29. Flint M, Patterson-Kane J, Mills P, Limpus C (2009) A veterinarian’s guide for sea turtle post mortem examination and histological investigation. The University of Queensland, p 56Google Scholar
  30. Fossette S, Girard C, López-Mendilaharsu M, Miller P, Domingo A, Evans D, Kelle L, Plot V, Prosdocimi L, Verhage S, Gaspar P, Georges JY (2010a) Atlantic leatherback migratory paths and temporary residence areas. PLoS ONE 5(11):e13908. doi: 10.1371/journal.pone.0013908 CrossRefGoogle Scholar
  31. Fossette S, Hobson VJ, Girard C, Calmettes B, Gaspar P, Georges JG, Hays GC (2010b) Spatio-temporal foraging patterns of a giant zooplanktivore, the leatherback turtle. J Mar Syst 81:225–234. doi: 10.1016/j.jmarsys.2009.12.002 CrossRefGoogle Scholar
  32. Fossette S, Gleiss AC, Casey JP, Lewis AR, Hays GC (2012) Does prey size matter? Novel observations of feeding in the leatherback turtle (Dermochelys coriacea) allow a test of predator–prey size relationships. Biol Lett 8:351–354. doi: 10.1098/rsbl.2011.0965 CrossRefGoogle Scholar
  33. García-Párraga D, Crespo-Picazo JL, de Quirós YB, Cervera V, Martí-Bonmati L, Díaz-Delgado J, Arbelo M, Moore MJ, Jepson PD, Fernández A (2014) Decompression sickness (“the bends”) in sea turtles. Dis Aquat Org 111:191–205. doi: 10.3354/dao02790 CrossRefGoogle Scholar
  34. Hart KM, Mooreside P, Crowder LB (2006) Interpreting the spatio-temporal patterns of sea turtle strandings: going with the flow. Biol Conserv 129:283–290. doi: 10.1016/j.biocon.2005.10.047 CrossRefGoogle Scholar
  35. Hawkes LA, Broderick AC, Coyne MS, Godfrey MH, Godley BJ (2007) Only some like it hot: quantifying the environmental niche of the loggerhead sea turtle. Divers Distrib 13(4):447–457. doi: 10.1111/j.1472-4642.2007.00354.x CrossRefGoogle Scholar
  36. Hays GC, Houghton JDR, Myers AE (2004) Endangered species: pan-Atlantic leatherback turtle movements. Nature 429:522. doi: 10.1038/429522a CrossRefGoogle Scholar
  37. Houghton JDR, Doyle TK, Wilson MW, Davenport J, Hays G (2006) Jellyfish aggregations and leatherback turtle foraging patterns in a temperate coastal environment. Ecology 87(8):1967–1972. doi: 10.1890/0012-9658 CrossRefGoogle Scholar
  38. INE (2013) Estatísticas da Pesca 2013. Instituto Nacional de EstatísticaGoogle Scholar
  39. IUCN (2014) The IUCN red List of threatened species. Version 2014.1 www.iucnredlist.org. Accessed on 26 June 2014
  40. Koch V, Peckham H, Mancini A, Eguchi T (2013) Estimating at-sea mortality of marine turtles from stranding frequencies and drifter experiments. PLoS ONE 8(2):e56776. doi: 10.1371/journal.pone.0056776 CrossRefGoogle Scholar
  41. Leeney RH, Amies R, Broderick AC, Witt MJ, Loveridge J, Doyle J, Godley BJ (2008) Spatio-temporal analysis of cetacean strandings and bycatch in a UK fisheries hotspot. Biodivers Conserv 17:2323–2338. doi: 10.1007/s10531-008-9377-5 CrossRefGoogle Scholar
  42. Lewison RL, Crowder LB (2007) Putting longlines bycatch of sea turtles into perspective. Conserv Biol 21:79–86. doi: 10.1111/j.1523-1739.2006.00592.x CrossRefGoogle Scholar
  43. López A, Covelo P, Valeiras X, Matínez-Cedeira JA (2014) Tartarugas mariñas nas costas de Galicia, s.XVIII—2013. Eubalena 13: 1–36. https://www.dropbox.com/s/bzdgbk46vbguywu/Eubalaena_13.pdf. Accessed 16 July 2014
  44. Mansfield KL, Putman NF (2013) Oceanic habits and habitats Caretta caretta. In: Wyneken J, Lohmann KJ, Musick JA (eds) The biology of sea turtles, vol III. CRC Press, Florida, pp 189–210CrossRefGoogle Scholar
  45. Mast RB, Hutchinson BJ, Howgate E, Pilcher NJ (2005) MTSG update: IUCN/SSC Marine Turtle Specialist Group host the Second Burning Issues Assessment Workshop. Mar Turt Newsl 110:13–15Google Scholar
  46. McMahon CR, Hays GC (2006) Thermal niche, large-scale movements and implications of climate change for a critically endangered marine vertebrate. Glob Change Biol 12:1330–1338. doi: 10.1111/j.1365-2486.2006.01174.x CrossRefGoogle Scholar
  47. Milton SL, Lutz PL (2003) Physiological and Genetic Responses to Environmental Stress. In: Lutz PL, Musick JA, Wyneken J (eds) The biology of sea turtles, vol II. CRC Press, Roca Raton, pp 163–197Google Scholar
  48. Monzón-Argüello C, Rico C, Carreras C, Calabuig P, Marco A, López-Jurado LF (2009) Variation in spatial distribution of juvenile loggerhead turtles in the eastern Atlantic and western Mediterranean Sea. J Exp Mar Biol Ecol 373:79–86CrossRefGoogle Scholar
  49. Moore MJ, van der Hoop J, Barco SG, Costidis AM, Gulland FM, Jepson PD et al (2013) Criteria and case definitions for serious injury and death of pinnipeds and cetaceans caused by anthropogenic trauma. Dis Aquat Organ 103:229–264. doi: 10.3354/dao02566 CrossRefGoogle Scholar
  50. Morreale SJ, Meylan AB, Sadove SS, Standora AE (1992) Annual occurrence and winter mortality of marine turtles in New York waters. J Herpetol 26(2):130–308Google Scholar
  51. Peckham SH, Diaz DM, Walli A, Ruiz G, Crowder LB, Nichols WJ (2007) Small-scale fisheries bycatch jeopardizes endangered Pacific loggerheads turtles. PLoS ONE 2(10):e1041. doi: 10.1371/journal.pone.0001041 CrossRefGoogle Scholar
  52. Peckham SH, Maldonado-Diaz D, Koch V, Mancini A, Gaos A, Tinker MT, Nichols WJ (2008) High mortality of loggerhead turtles due to bycatch, human consumption and stranding at Baja California Sur, Mexico, 2003 to 2007. Endanger Species Res 5:171–183. doi: 10.3354/esr00123 CrossRefGoogle Scholar
  53. Peltier H, Dabin W, Daniel P, Van Canneyt O, Dorémus G, Huon M, Ridoux V (2012) The significance of stranding data as indicators of cetacean populations at sea: modeling the drift of cetacean carcasses. Ecol Indic 18:278–290. doi: 10.1016/j.ecolind.2011.11.014 CrossRefGoogle Scholar
  54. Pierpoint C (2000) Bycatch of marine turtles in UK and Irish waters. JNCC, Report No 310 Google Scholar
  55. Prieto L, Armani A, Macías D (2013) Recent strandings of the giant jellyfish Rhizostoma luteum Quoy and Gaimard, 1827 (Cnidaria: Schyphozoa: Rhizostomeae) on the Atlantic and Mediterranean coasts. Mar Biol 160:3241–3247. doi: 10.1007/s00227-013-2293-6 CrossRefGoogle Scholar
  56. Quinn GP, Keough MJ (2002) Experimental design and data analysis for biologists. Cambridge University Press, CambridgeCrossRefGoogle Scholar
  57. Relvas P, Barton E (2005) A separated jet and coastal counter-flow during upwelling relaxation off Cape São Vicente (Iberian Peninsula). Cont Shelf Res 25:29–49. doi: 10.1016/j.csr.2004.09.006 CrossRefGoogle Scholar
  58. Schwartz FJ (1978) Behavioral and tolerance responses to cold water temperatures by three species of sea turtles (Reptilia, Cheloniidae) in North Carolina. In: Henderson GE (ed) Proceedings of the Florida interregional conference on sea turtles. Florida Marine Research Publication 33, pp 16–18Google Scholar
  59. Spotila JR, O’Connor MP, Paladino F (1997) Thermal biology. In: Lutz PL, Musick JA (eds) The biology of sea turtles. CRC marine species series. RC Press, Boca Raton, pp 297–314Google Scholar
  60. Stewart K, Johnson C, Godfrey MH (2007) The minimum size of leatherbacks at reproductive maturity, with a review of sizes for nesting females from the Indian, Atlantic and Pacific Ocean basins. Herpet J 17:123–128Google Scholar
  61. Tomás J, Gozalbes P, Raga JA, Godley BJ (2008) Bycatch of loggerhead sea turtles: insights from 14 years of strandings data. Endanger Species Res 5:167–169. doi: 10.3354/esr00116 CrossRefGoogle Scholar
  62. TEWG, Turtle Expert Working Group (2009) An assessment of the Loggerhead turtle population in the Western North Atlantic Ocean. NOAA Technical Memorandum NMFS-SEFSC-575Google Scholar
  63. Vélez-Rubio GM, Estrades A, Fallabrino A, Tomás J (2013) Marine turtle threats in Uruguayan waters: insights from 12 years of strandings data. Mar Biol 160:2797–2811. doi: 10.1007/s00227-013-2272-y CrossRefGoogle Scholar
  64. Wallace BP, DiMatteo AD, Brendan JH, Finkbeiner EM, Bolten AB et al (2010) Regional management units for marine turtles: a novel framework for prioritizing conservation and research across multiple scales. PLoS ONE 5(12):e15465. doi: 10.1371/journal.pone.0015465 CrossRefGoogle Scholar
  65. Wallace BP, DiMatteo AD, Bolten AB, Chaloupka MY, Hutchinson BJ et al (2011) Global conservation priorities for marine turtles. PLoS ONE 6(9):e24510. doi: 10.1371/journal.pone.0024510 CrossRefGoogle Scholar
  66. Witt MJ, Broderick AC, Jonhs DJ, Martin C, Penrose R, Hoogmoed MS, Godley BJ (2007a) Prey-landscapes help identify potential foraging habitats for leatherbacks turtles in the NE Atlantic. Mar Ecol Prog Ser 337:231–243. doi: 10.3354/meps337231 CrossRefGoogle Scholar
  67. Witt MJ, Penrose R, Godley BJ (2007b) Spatio-temporal patterns of juvenile marine turtle occurrence in waters of the European mainland shelf. Mar Biol 151:873–885. doi: 10.1007/s00227-006-0532-9 CrossRefGoogle Scholar
  68. Witt MJ, Hawkes LA, Godfrey MH, Godley BJ, Broderick AC (2010) Predicting the impacts of climate change in globally distributed species: the case of loggerhead turtle. J Exp Biol 213:901–911. doi: 10.1242/jeb.038133 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Lídia Nicolau
    • 1
    • 2
  • Marisa Ferreira
    • 2
    • 3
  • Jorge Santos
    • 1
    • 2
  • Hélder Araújo
    • 1
    • 2
  • Marina Sequeira
    • 4
  • José Vingada
    • 2
    • 5
  • Catarina Eira
    • 1
    • 2
  • Ana Marçalo
    • 1
    • 2
  1. 1.Departamento de Biologia e Centro de Estudos do Ambiente e do Mar (CESAM)Universidade de AveiroAveiroPortugal
  2. 2.Sociedade Portuguesa de Vida Selvagem (SPVS), Departamento BiologiaUniversidade do MinhoBragaPortugal
  3. 3.Departamento Biologia, Centro de Biologia Molecular e Ambiental (CBMA)Universidade do MinhoBragaPortugal
  4. 4.Instituto da Conservação da Natureza e das Florestas (ICNF)LisbonPortugal
  5. 5.Departamento de Biologia e Centro de Estudos do Ambiente e do Mar (CESAM)Universidade do MinhoBragaPortugal

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