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Speed of travel of migrating Green turtles (Chelonia mydas) from Ascension Island to Brazil. / Pilar Santidrian Tomillo

Swansea University Author: Pilar Santidrian Tomillo

Abstract

This thesis investigates the speed of travel during migration from Ascension Island to Brazil of 12 female green sea turtles (Chelonia niydas). Diving behaviour (Mean dive duration, standard deviation of the mean dive duration and number of dives), the prevailing oceanic currents (north-south compon...

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Published: 2002
Institution: Swansea University
Degree level: Master of Philosophy
Degree name: M.Phil
URI: https://cronfa.swan.ac.uk/Record/cronfa42601
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Abstract: This thesis investigates the speed of travel during migration from Ascension Island to Brazil of 12 female green sea turtles (Chelonia niydas). Diving behaviour (Mean dive duration, standard deviation of the mean dive duration and number of dives), the prevailing oceanic currents (north-south component, east-west component, speed of the current and angle between the direction of the current and the direction of the turtle) and size, were analysed to determine their possible influence on the speed of travel. Two different methods were applied: (1) a detailed analysis made by dividing the migration route into pixels of 1.25° longitude x 1.25° latitude and (2) a general study on the overall speed of travel. The mean speed of travel of migrating Ascension Island green turtles was found to be 2.59 km/h, most likely to be the speed at which the Cost of Transport (COT) is minimal. The speed of migrating turtles from Ascension Island depends on the mean duration of dives, the number of dives and the angle between the direction they follow and that of the prevailing current. The main factor explaining the variation of the speed of travel of Ascension Island turtles is the duration of the dives. Mean dive duration, its standard deviation and number of dives, are related to the size of the turtles.
Keywords: Biological oceanography.
College: Faculty of Science and Engineering

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