@article {14440,
	title = {Metabolic heating in Mediterranean loggerhead sea turtle clutches},
	journal = {Journal of Experimental Marine Biology and EcologyJournal of Experimental Marine Biology and Ecology},
	volume = {334},
	number = {1},
	year = {2006},
	note = {Cited By (since 1996): 1Export Date: 4 September 2006Source: ScopusReferences: Ackerman, R.A., The nest environment and the embryonic development of sea turtles (1997) The Biology of Sea Turtles, pp. 83-106. , Lutz P.L., and Musick J.A. (Eds), CRC Press, Boca Raton; Booth, D.T., Astill, K., Temperature variation within and between nests of the green sea turtle, Chelonia mydas (Chelonia: Cheloniidae) on Heron Island, Great Barier Reef (2001) Australian Journal of Zoology, 49, pp. 71-84; Broderick, A.C., Godley, B.J., Hays, G.C., Metabolic heating and the prediction of sex ratios for green turtles (Chelonia mydas) (2001) Physiological and Biochemical Zoology, 74, pp. 161-170; Carr, A., Hirth, H., Social facilitation in green turtle siblings (1961) Animal Behaviour, 9, pp. 68-70; Ewert, M.A., Nelson, C.E., Metabolic heating of embryos and sex determination in the American alligator, Alligator mississippiensis (2003) Journal of Thermal Biology, 28, pp. 159-165; Glen, F., Mrosovsky, N., Antigua revisited: the impact of climate change on sand and nest temperatures at a hawksbill turtle (Eretmochelys imbricata) nesting beach (2004) Global Change Biology, 10, pp. 2036-2045; Godfrey, M.H., Mrosovsky, N., Estimating the time between hatching of sea turtles and their emergence from the nest (1997) Chelonian Conservation and Biology, 2, pp. 581-585; Godfrey, M.H., Barreto, R., Mrosovsky, N., Metabolically-generated heat of developing eggs and its potential effect on sex ratio of sea turtle hatchlings (1997) Journal of Herpetology, 31, pp. 616-619; Godley, B.J., Broderick, A.C., Downie, J.R., Glen, F., Houghton, J.D., Kirkwood, I., Reece, S., Hays, G.C., Thermal conditions in nests of loggerhead turtles: further evidence suggesting female skewed sex ratios of hatchling production in the Mediterranean (2001) Journal of Experimental Marine Biology and Ecology, 263, pp. 45-63; Hanson, J., Wibbles, T., Martin, R.E., Predicted female bias in sex ratios of hatchling loggerhead sea turtles from a Florida nesting beach (1998) Canadian Journal of Zoology, 76, pp. 1850-1861; Houghton, J.D.R., Hays, G.C., Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings (2001) Naturwissenschaften, 88, pp. 133-136; Kaska, Y., Downie, R., Tippett, R., Furness, R.W., Natural temperature regimes for loggerhead and green turtle nests in the eastern Mediterranean (1998) Canadian Journal of Zoology, 76, pp. 723-729; Margaritoulis, D., Rees, A.F., Loggerhead nesting effort and conservation initiatives at the monitored beaches of Greece during 2002 (2003) Marine Turtle Newsletter, 102, pp. 11-13; Margaritoulis, D., Argano, R., Baran, I., Bentivegna, F., Bradai, M.N., Camin?as, J.A., Casale, P., (...), Lazar, B., Loggerhead turtles in the Mediterranean Sea: present knowledge and conservation perspectives (2003) Loggerhead Sea Turtles, pp. 175-198. , Bolten A.B., and Witherington B.E. (Eds), Smithsonian Institution, Washington; Miller, J.D., Embryology of marine turtles (1985) Biology of Reptilia, Development A, pp. 269-328. , Gans C., Billett F., and Maderson P.F.A. (Eds), John Wiley and Sons, New York; Miller, J.D., Determining clutch size and hatching success (1999) Research and Management Techniques for the Conservation of Sea Turtles, pp. 124-129. , Eckert K.L., Bjorndal K.A., Abreu-Grobois F.A., and Donnelly M. (Eds), IUCN/SSC Marine Turtle Specialist Group, Washington, DC; Mrosovsky, N., Pieau, C., Transitional range of temperature, pivotal temperatures and thermosensitive stages for sex determination in reptiles (1991) Amphibia-Reptilia, 12, pp. 169-179; Mrosovsky, N., Baptistotte, C., Godfrey, M.H., Validation of incubation duration as an index of the sex ratio of hatchling sea turtles (1999) Canadian Journal of Zoology, 77, pp. 831-835; Mrosovsky, N., Kamel, S., Rees, A.F., Margaritoulis, D., Pivotal temperature for loggerhead turtles (Caretta caretta) from Kyparissia Bay, Greece (2002) Canadian Journal of Zoology, 80, pp. 2118-2124; Speakman, J.R., Hays, G.C., Lindblad, E., Thermal conductivity of sand and its effect on the temperature of loggerhead sea turtle (Caretta caretta) nests (1998) Journal of the Marine Biological Association of the United Kingdom, 78, pp. 1337-1352; Tiwari, M., Bjorndal, K.A., Variation in morphology and reproduction in loggerheads, Caretta caretta, nesting in the United States, Brazil, and Greece (2000) Herpetologica, 56, pp. 343-356.},
	month = {2006///},
	pages = {151-157},
	abstract = {Offspring sex ratio is an important demographic parameter and, given its determination by incubation temperature in sea turtles, might be a key factor for their conservation under climate warming. An appealing approach to estimate hatchling sex ratios is to measure sand temperatures at nest depth and deduce hatchling sex ratios from a beforehand-established relationship of hatchling sex ratio and sand temperature. Such estimates will only be accurate though if metabolic heat produced by the embryos is considered. Judging whether metabolic heating has a potential effect on hatchling sex ratios without actually measuring temperature within clutches would greatly facilitate monitoring protocols. We tested for a relationship between the amount of metabolic heating and the number of developed embryos as well as clutch size in the largest known loggerhead sea turtle (Caretta caretta) population of the Mediterranean on Zakynthos (Greece). Temperatures were measured within 20 nests as well as at a reference site in the sand at nest depth. Metabolic heating was detected, but only during the last third of the incubation period did nests heat up considerably (1.6 {\textdegree}C on average) above the temperature of the surrounding sand. During the middle third of incubation, when sex is determined, the amount of metabolic heating was negligible. The amount of metabolic heating during the last third of the incubation duration was significantly correlated to the number of offspring developed to at least about 75\% of incubation duration. This factor explained nearly 50\% of variation in metabolic heating. Metabolic heating was also significantly correlated to clutch size. Given that clutch size within the Mediterranean is largest in Zakynthos loggerheads, we conclude that metabolic heating can be ignored in the estimate of hatchling sex ratios in Mediterranean loggerhead populations. These results thus provide the basis for a feasible monitoring of hatchling sex ratios in the loggerhead sea turtle in the Mediterranean. {\textcopyright} 2006 Elsevier B.V. All rights reserved.},
	keywords = {Caretta caretta, Hatchling sex ratio, Mediterranean, Metabolic heating, Reptilia, Temperature-dependent sex determination},
	author = {Zbinden, J.A. and Margaritoulis, D. and Arlettaz, R.}
}
