Studies on the embryology, ecology and evolution of sea turtles in the Eastern Mediterranean

QH301 Biology;QL Zoology

Kaska, Yakup ; Furness, R.W.

University:University of Glasgow

Department:Institute of Biodiversity Animal Health and Comparative Medicine

关键词: QH301 Biology;    QL Zoology;   

Others  :  http://theses.gla.ac.uk/5321/2/thesiscoversheet.pdf

来源: University of Glasgow

【 摘 要 】

1-) The temperature of sea turtle nests in the Eastern Mediterranean was between 24 and35 "C and rose by up to 10 "C during incubation.2-) The mean incubation temperature can be used for estimating the incubation periodbut provides a poor prediction of sex ratio.3-) The mean temperature during the middle third of the incubation period was closelycorrelated with the percent sex ratio.4-) There was a female dominated sex ratio among the 22 nests and only one loggerheadturtle nest showed less than a 50 % female sex ratio.5-) There was a consistent temperature difference within the nest with top eggs warmer,bottom eggs cooler and middle ones intermediate. Therefore the majority of hatchlings11'0111 [he top level in nests were females and those from the bottom level werepredominantly males.6-) Temperature differences within the nest also influenced the rate of development; thegreater the difference in temperature between top and bottom the longer the timerequired to complete hatching of all embryos of the nest. The hatching intervals of greenturtle nests were shorter than those at loggerhead turtle nests. Temperature variationbetween top and bottom of nests was low within green turtle nests. In general, a 1 "Ctemperature difference within the clutch caused a 4 day range in both hatching andemergence of hatchlings.7-) Since the temperature within the nest and between the nests was so variable, sand airor sea water temperatures gave a poor prediction of the temperature of a nest andtherefore the sex ratio.8-) Although the predation pattern of sea turtle nests varied in relation to nest age, thispredation can be reduced by screening the nest with mesh grids.9-) lnundation was one of the main abiotic factors lowering the hatching success on thebeaches. Hatching success can be increased by relocating the nests to a safer area on thenight of laying10-) The mean grain sizes of sand ranged from 0.49 to 2.20 phi(