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Title: Studies on the behaviour and ecology of hatching and adult sea turtles
Author: Glen, F.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2003
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The timing of emergence of green turtle (Chelonia mydas) hatchlings from their nest on two beaches on Ascension Island was monitored. Emergence of hatchlings predominantly occurred at night, and was inhibited by increasing temperatures at superficial sand depths. No single thermal cue was found to play a role during the emergence of loggerhead turtle (Caretta caretta) and green turtle hatchlings from their nests on Cyprus. No difference in temperature within loggerhead and green turtle clutches was observed in northern Cyprus and on Ascension Island. The magnitude of metabolic heating during the final third of incubation, was positively related to clutch volume. A comparison of body size and flipper size was carried out on green turtle hatchlings from Ascension Island and Cyprus. Ascension Island hatchlings were larger than hatchlings from Cyprus. Incubation temperature appeared to influence body size on Ascension Island, with higher temperatures producing smaller hatchlings. Rhythmic throat movements were recorded during the various nesting stages of green turtles on Ascension Island. Throat movements occurred consistently during the various stages, although were statistically lower during egg deposition. Female green turtles were weighed post oviposition during nesting at Ascension Island. Turtles were found to lose 0.22kgd-1, as they do not feed during their time at the island. A dichotomy in depth utilisation between green turtles during their interesting interval in Ascension Island and Cyprus was observed. This difference was attributed to differences in food availability at the two sites. Depth and swim speed during U-dives carried out by a green turtle were measured during the inter nesting period in Cyprus. Typically the turtle initially descended at a steep angle (around 60°) but as the dive continued this angle lessened until the turtle approached the seabed at an average angle of about 15°.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available