Embryonic Mortality in Loggerhead Turtle (Caretta caretta) Nests: A Comparative Study on Fethiye and Göksu Delta Beaches

In total, 66 loggerhead turtle nests were examined and compared in terms of embryonic mortality during the 2004 and 2005 breeding seasons on Fethiye and Göksu Delta beaches. In all, 5012 eggs were counted, 2751 (54.90%) of which hatched successfully. Of the 2261 unhatched eggs, 68 (1.35%) were classified as unidentified eggs and 2193 (43.75%) were classified as containing dead embryos. Of these dead embryos, a high percentage were in the early stage (n = 1177, 23.48%) and late stage (n = 814, 16.24%,) of development. The lowest percentage of the eggs with dead embryos (n = 202, 4.03%) were in the mid-stage of development. The embryonic mortality rate was higher at Göksu Delta than at Fethiye Beach. Of the examined ecological variables, none accounted for the early stage embryonic mortality. Embryonic mortality in the middle and late stages of development increased with decreasing slope and dry sand depth of the nests; however, embryonic mortality during these stages decreased with declining moisture and wet sand depth of the nests.

Embryonic Mortality in Loggerhead Turtle (Caretta caretta) Nests: A Comparative Study on Fethiye and Göksu Delta Beaches

In total, 66 loggerhead turtle nests were examined and compared in terms of embryonic mortality during the 2004 and 2005 breeding seasons on Fethiye and Göksu Delta beaches. In all, 5012 eggs were counted, 2751 (54.90%) of which hatched successfully. Of the 2261 unhatched eggs, 68 (1.35%) were classified as unidentified eggs and 2193 (43.75%) were classified as containing dead embryos. Of these dead embryos, a high percentage were in the early stage (n = 1177, 23.48%) and late stage (n = 814, 16.24%,) of development. The lowest percentage of the eggs with dead embryos (n = 202, 4.03%) were in the mid-stage of development. The embryonic mortality rate was higher at Göksu Delta than at Fethiye Beach. Of the examined ecological variables, none accounted for the early stage embryonic mortality. Embryonic mortality in the middle and late stages of development increased with decreasing slope and dry sand depth of the nests; however, embryonic mortality during these stages decreased with declining moisture and wet sand depth of the nests.

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  • Ackerman, R.A. 1980. Physiological and ecological aspects of gas exchange by sea turtle eggs. American Zoologist, 20: 575-583.
  • Ackerman, R.A. 1997. The Nest Environment and the Embryonic Development of Sea Turtles. In: The Biology of Sea Turtles (eds. P. L. Lutz and J. A. Musick), CRC Press, Boca Raton, FL, pp. 83- 106.
  • Blanck, C.E. and Sawyer, R.H. 1981. Hatchery practices in relation to early embryology of the loggerhead sea turtle, Caretta caretta (Linné). Journal of Experimental Marine Biology and Ecology, 49: 163-177.
  • Bolten, A.B., Bjorndal, K.A., Martins, H.R., Dellinger, T., Biscoito, M.J., Encalada, S.E. and Bowen, B.W. 1998. Transatlantic developmental migrations of loggerhead sea turtles demonstrated by mtDNA sequence analysis. Ecol. Appl. 8: 1-7.
  • Broderick, A.C., Glen, F., Godley, B.J. and Hays, G.C. 2002. Estimating the number of Green and Loggerhead Turtles nesting annually in the Mediterranean. Oryx, 36: 1-9.
  • Bustard, H.R. and Greenham, P. 1968. Physical and chemical factors affecting hatching in the green sea turtle, Chelonia mydas L. Ecology, 49: 269-276.
  • Canbolat, A.F. 2004. A review of sea turtle nesting activity along the mediterranean coast of Turkey. Biol. Conserv. 116: 81-91.
  • Çıtak, T. 1998. An investigation on ecological conditions effects to embryological development in marine turtle populations. M.Sc. Thesis, Dokuz Eylül University, İzmir.
  • Head, K.H. 1992. Manual of Soil Laboratory Testing. Halsted Press, New York.
  • Hendrickson, J.R. 1958. The green sea turtle, Chelonia mydas (Linn.), in Malaya and Sarawak. Proceedings of Zoological Society of London. 130: 455-535.
  • Horrocks, J.A. and Scott, N.M. 1991. Nest site location and nest success in the hawksbill turtle (Eretmochelys imbricata) in Barbados, West Indies. Mar. Ecol. Prog. Ser. 69: 1-8.
  • IUCN 2006. 2006 IUCN Red List of Treatened Species. . Downloaded on 07 Feb. 2007.
  • Kaska, Y. and Downie, R. 1999. Embryological development of sea turtles (Chelonia mydas, Caretta caretta) in the Mediterranean. Zool. in the Middle East. 19: 55-69.
  • Kaska, Y., Ilgaz, Ç., Özdemir, A., Başkale, E., Türkozan, O., Baran, İ. and Stachowitsch, M. 2006. Sex ratio estimations of loggerhead sea turtle hatchlings by histological examination and nest temperatures at Fethiye beach, Turkey. Naturwissenschaften, 93: 338-343.
  • Limpus, C.J., Baker, V. and Miller, J.D. 1979. Movement induced mortality of loggerhead eggs. Herpetologica. 35: 335-338.
  • Margaritoulis, D., Argano, R., Baran, I., Bentivegna, F., Bradai, M.N., Caminas, J.A., Casale, P., De Metrio, G., Demetropulos, A., Gerosa, G., Brendan, J.G., Haddoud, D.A., Houghton, J., Laurent, L. and Lazar, B. 2003. Loggerhead Turtles in the Mediterranean Sea: Present Knowledge and Conservation Perspectives. In: Loggerhead Sea Turtles (eds. Bolten, A.B. and Witherington, B.E.). Smithsonian Books, Washington, DC, Chap. 11, pp. 175–198.
  • Miller, J. D. 1985. Embryology of Marine Turtles. In: Biology of the Reptilia (eds. Gans, C., Northcutt, R.G. and Ulinsky, P.). London & New York, Vol. 14, pp. 269-328.
  • Mrosovsky, N. 1980. Thermal biology of sea turtles. American Zoologist. 20: 531-547.
  • Özdemir, B. and Türkozan, O. 2006. Hatching success of green turtle, Chelonia mydas, clutches in relation biotic and abiotic factors in Northern Cyprus. Turk. J. Zool. 30: 377-381.
  • Özdemir, A., Ilgaz, Ç., Kumlutaş Y., Durmuş, S.H., Kaska, Y. and Türkozan, O. 2007. An assessment of initial body size in loggerhead sea turtle (Caretta caretta) hatchlings in Turkey. Zoological Science, 24: 376-380.
  • Prange, H.D. and Ackerman, R.A. 1974. Oxygen consumption and mechanism of gas exchange of the green turtle (Chelonia mydas) eggs and hatchlings. Copeia, 166-173.
  • Spss, Inc. 2001.SPSS for windows.Lead Technologies Inc, version 11.0.1.
  • Taşkın, N. 1998. Patara kumsalı’ndaki deniz kaplumbağası populasyonunun embriyolojik gelişiminin incelenmesi. M.Sc. Thesis, Dokuz Eylül University, İzmir.
  • Türkozan, O. 2000. Reproductive ecology of the loggerhead turtle, Caretta caretta, on Fethiye and Kızılot beaches, Turkey. Chelonian Cons. and Biol. 3: 686-692.
  • Türkozan, O., Ilgaz, Ç., Taşkavak, E. and Özdemir, A. 2003. Hatch rates of loggerhead turtles and physical characteristics of the beach at Fethiye, Turkey. J. Mar. Biol. Ass. U.K. 83: 231-232.
  • Whitmore, C.P. and Dutton, P.H. 1985. Infertility, embryonic mortality and nest site selection in leatherback and green sea turtles in Suriname. Biol. Conserv. 34: 251-272.
  • Wood, D.W. and Bjorndal, K.A. 2000. Relation of temperature, moisture, salinity, and slope to nest site selection in loggerhead sea turtles. Copeia, 1: 119-128.
  • Yerli, S., Canbolat, A.F., Macdonald, D.W. and Brown, L. 1997. Mesh grids protect loggerhead turtles, Caretta caretta nests from red fox Vulpes vulpes predation. Biological Conservation, 82: 109- 111.
Turkish Journal of Zoology-Cover
  • ISSN: 1300-0179
  • Yayın Aralığı: Yılda 6 Sayı
  • Yayıncı: TÜBİTAK
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