Scientia Marina, Vol 75, No 3 (2011)

The North Atlantic Oscillation and sea surface temperature affect loggerhead abundance around the Strait of Gibraltar

José C. Báez
Instituto Español de Oceanografia (IEO), Centro Oceanográfico de Málaga - Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga , Spain

Juan J. Bellido
Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga - Aula del Mar de Málaga , Spain

Francisco Ferri-Yáñez
Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga - Consejo Superior de Investigaciones Científicas , Spain

Juan J. Castillo
Aula del Mar de Málaga , Spain

Juan J. Martín
Aula del Mar de Málaga , Spain

José L. Mons
Aula del Mar de Málaga , Spain

David Romero
Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga , Spain

Raimundo Real
Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga , Spain


The aim of this study was to explore the possible link between variations in the North Atlantic Oscillation (NAO) and sea surface temperature (SST) and the abundance of loggerhead turtles around the Strait of Gibraltar, using stranding data for the Andalusian coastal area as a proxy for abundance. The annual average SST (from November to October) in the Gulf of Cadiz was negatively associated with the total number of loggerhead strandings each year from November 1997 to October 2006 in the Gulf of Cadiz and the Alboran Sea. The average NAO index was positively associated with the number of strandings in the Gulf of Cadiz in the following year. Prevailing westerly winds during positive NAO phases and the subsequent delayed decrease in SST may lead to turtles from the west Atlantic accumulating in the Gulf of Cadiz and unsuccessfully attempting to return. Secondary causes, such as buoyancy, cold stunning, longline fisheries, net fisheries, debilitated turtle syndrome, and trauma may also increase the number of turtle strandings.


global change; Gulf of Cadiz; marine migratory species; Mediterranean Sea; sea turtle

Full Text:



Bellido, J.J., J.C. Báez, J.J. Castillo, F. Pinto, J.J. Martín, J.L. Mons and R. Real. - 2008. Mass strandings of cold-stunned loggerhead turtles in the south Iberian Peninsula: ethological implications. Ethol. Ecol. Evol., 20: 401-405. PMid:7610347

Bellido, J.J., J.J. Castillo, F. Pinto, J.J. Martín, J.L. Mons, J.C. Báez and R. Real. - 2010. Differential geographical trends for loggerhead turtles stranding dead or alive along the Andalusian coast, southern Spain. J. Mar. Biol. Assoc. UK., 90: 225-231. Camiñas, J.A. and J.M. de la Serna. - 1995. The loggerhead distribution in the western Mediterranean Sea as deduced from captures by the Spanish longline fishery. In: G.A. Llorente, A. Montori, X. Santos and M.A. Carretero, (eds.). Sci. Herpet., 316-323.

Chaloupka, M., T.M. Work, G.H. Balazs, S.K.K. Murakawa and R. Morris. - 2008a. Cause-specific temporal and spatial trends in green sea turtle strandings in the Hawaiian Archipelago (1982-2003). Mar. Biol., 154: 887-898. PMid:18564127

Chaloupka, M., N. Kamezaki and C. Limpus. - 2008b. Is climate change affecting the population dynamics of the endangered Pacific loggerhead sea turtle? J. Exp. Mar. Biol. Ecol., 356: 136-143. PMid:18955161

D´Alba, L., P. Monaghan and R.G. Nager. - 2010. Advances in laying date and increasing population size suggest positive responses to climate change in Common Eiders Somateria mollissima in Iceland. Ibis, 152: 19-28.

Eckert, S.A., J.E. Moore, D.C. Dunn, R.S. van Buiten, K.L. Eckert and P.N. Halpin. - 2008.- Modeling loggerhead turtle movement in the Mediterranean: importance of body size and oceanography. Ecol. Appl., 18: 290-308. PMid:11473328

Epperly, S.P., J. Braun, A.J. Chester, F.A Cross, J.V. Merriner, P.A. Tester and J.H. Churchill. - 1996. Beach strandings as an indicator of at-sea mortality of sea turtles. Bull. Mar. Sci., 59(2): 289-297. PMid:3262200

Gancedo, U., E. Zorita, A.P. Solari, G. Chust, A.S. del Pino, J. Polanco and J.J. Castro. - 2009. What drove tuna catches between 1525 and 1756 in southern Europe? ICES J. Mar. Sci., 66: 1595-1604. PMid:11207865

Goñi, N. and H. Arrizabalaga. - 2005. Analysis of juvenile North Atlantic Albacore (Thunnus alalunga) catch per unit effort by surface gears in relation to environmental variables. ICES J. Mar. Sci., 62:1475-1482.

Graham, C.T. and C. Harrold. - 2009. Implications of climate change for the fishes of the British Isles. J. Fish Biol., 74: 1143-1205. PMid:9437376

Hawkes, LA, A.C. Broderick, M.S. Coyne, M.H. Godfrey and B.J. Godley. - 2007a. Only some like it hot - quantifying the environmental niche of the loggerhead sea turtle. Diver. Distrib., 13: 447-457. PMid:11668406

Hawkes, L.A., A. Broderick, M. Godfrey and B.J. Godley. - 2007b. Investigating the potential impacts of climate change on a marine turtle population. Global Change Biol., 13: 923-932. PMid:12244498

Hurrell, J.W. - 1995. Decadal trends in the North Atlantic Oscillation: Regional temperatures and precipitation. Science, 269: 676-679. PMid:9462402

Day, R.D., J.M. Keller, C.A. Harms, A.L. Segars, W.M. Cluse, M.H. Godfrey, A.M. Lee, M. Peden-Adams, K. Thorvalson, M. Dodd and T. Norton. - 2010. comparison of mercury burdens in chronically debilitated and healthy loggerhead sea turtles (Caretta caretta). J. Wildl. Dis., 46(1): 111-117.

Mazaris, A., A. Kallimanis, S. Sgardelis and J. Pantis. - 2008. Do long-term changes in sea surface temperature at the breeding areas affect the breeding dates and reproduction performance of Mediterranean loggerhead turtles? Implications for climate change. J. Exp. Mar. Biol. Ecol., 367: 219-226. PMid:17352364

McCallum, M.L., J.L. McCallum and S.E. Trauth. - 2009. Predicted climate change may spark box turtle declines. Amphibia-Reptilia, 30: 259-264. PMid:11870374

MacLeod, C., G. Pierce and M. Santos. - 2004. Geographic and temporal variations in strandings of beaked whales (Ziphiidae) on the coasts of the UK and the Republic of Ireland from 1800-2002. J. Cetacean Res. Manage., 6: 79-86.

Monzon-Arguello, C., C. Rico, E. Naro-Maciel, N. Varo-Cruz, P. López, A. Marco and L.F. López-Jurado. - 2010. Population structure and conservation implications for the loggerhead sea turtle of the Cape Verde Islands. Conserv. Genet., 11: 1871-1884.

Peng, S., W.A. Robinson and S. Li. - 2002. North Atlantic SST Forcing of the NAO and Relationships with Intrinsic Hemispheric Variability. Geophys. Res. Lett., 29: 1276-1280 DOI10.1029/2001GL014043.

Robinson, A.R., H. Crick, J.A. Learmonth, I.M.D. Maclean, C.D. Thomas, F. Bairlein, M.C. Forchhammer, C.M. Francis, J.A. Gill, B.J. Godley, J. Harwood, G.C. Hays, B. Huntley, A.M. Hutson, G.J. Pierce, M.M. Rehfisch, D.W. Sims, M.B. Santos, T.H. Sparks, D.A. Stroud and M.E. Visser. - 2008. Travelling through a warming world: climate change and migratory species. Endang. Species Res., 7: 87-99.

Sánchez, R.F., P. Relvas and M. Delgado. - 2007. Coupled ocean wind and sea surface temperature patterns off the western Iberian Peninsula. J. Mar. Syst., 68: 103-127.

Sims, D.W., M.J. Genner, A.J. Southward, S.J. Hawkins. - 2001. Timing of squid migration reflects North Atlantic climate variability. P. Roy. Soc. B-Biol. Sci., 268: 2607-2611Schofield, G., C.M. Bishop, K.A. Katselidis, P. Dimopoulos, J.D. Pantis and G.C. Hays. - 2009. Microhabitat selection by sea turtles in a dynamic thermal marine environment. J. Anim. Ecol., 78: 14-21.

Tomás, J., P. Gozalbes, J.A. Raga and B.J. Godley. - 2008. Bycatch of loggerhead sea turtles: insights from 14 years of stranding data. Endang. Species Res., 5: 167-169.

Trigo, R.M., D. Pozo-Vázquez, T.J. Osborn, Y. Castro-Díez, S. Gámiz-Fortis and M.J. Esteban-Parra. - 2004. North Atlantic Oscillation influence on precipitation, river flow and water resources in the Iberian Peninsula. Int. J. Climatol., 24: 925-944.

Visbeck, M.H., J.W. Hurrell, L. Polvani and H.M. Cullen. - 2001. The North Atlantic Oscillation: Past, present, and future. P. Natl. Acad. Sci. USA, 98: 12876-12877.

Watson, J.W., S.P. Epperly, A.K. Shah and D.G. Foster. - 2005. Fishing methods to reduce sea turtle mortality associated with pelagic longlines. Can. J. Fish. Aquat. Sci., 62: 965-981.

Weishampel, J.F., D.A. Bagley and L.M. Ehrhart. - 2004. Earlier nesting by loggerhead sea turtles following surface warming. Global Change Biol., 10: 1-4.

Witt, M.J., R. Penrose and B.J. Godley. - 2007. Spatio-temporal patterns of juvenile marine turtle occurrence in waters of the European continental shelf. Mar. Biol., 151: 873-885.

Witt, M.J., L.A. Hawkes, M.H. Godfrey, B.J. Godley and A.C. Broderick. - 2010. Predicting the impacts of climate change on a globally distributed species: the case of the loggerhead turtle. J. Exp. Biol., 213: 901-911.

Copyright (c) 2011 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Contact us

Technical support