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The diving behaviour of green turtles undertaking oceanic migration to and from Ascension Island: dive durations, dive profiles and depth distribution

Author:
  • G. C. Hays
  • Susanne Åkesson
  • A. C. Broderick
  • F. Glen
  • B. J. Godley
  • P. Luschi
  • C. Martin
  • D. Metcalfe
  • F. Papi
Publishing year: 2001
Language: English
Pages: 4093-4098
Publication/Series: Journal of Experimental Biology
Volume: 204
Issue: 23
Document type: Journal article
Publisher: The Company of Biologists Ltd

Abstract english

Satellite telemetry was used to record the submergence duration of green turtles (Chelonia mydas) as they migrated from Ascension Island to Brazil (N=12 individuals) while time/depth recorders (TDRs) were used to examine the depth distribution and dive profiles of individuals returning to Ascension Island to nest after experimental displacement (N=5 individuals). Satellite telemetry revealed that most submergences were short (<5 min) but that some submergences were longer (>20 min), particularly at night. TDRs revealed that much of the time was spent conducting short (24 min), shallow (approximately 0.91.5 m) dives, consistent with predictions for optimisation of near-surface travelling, while long (typically 2030 min), deep (typically 1020 m) dives had a distinctive profile found in other marine reptiles. These results suggest that green turtles crossing the Atlantic do not behave invariantly, but instead alternate between periods of travelling just beneath the surface and diving deeper. These deep dives may have evolved to reduce silhouetting against the surface, which would make turtles more susceptible to visual predators such as large sharks.

Keywords

  • Biological Sciences

Other

Published
  • ISSN: 1477-9145
Susanne Åkesson
E-mail: susanne [dot] akesson [at] biol [dot] lu [dot] se

Professor

Evolutionary ecology

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