hays-satellitetracking-2007.pdf (1.55 MB)
Satellite tracking reveals unusual diving characteristics for a marine reptile, the olive ridley turtle : Lepidochelys olivacea
journal contribution
posted on 2007-01-01, 00:00 authored by C McMahon, C Bradshaw, Graeme HaysGraeme HaysThe movements, diving behaviour and thermal environment occupied by 4 adult female olive ridley turtles Lepidochelys olivacea in northern Australia were determined through satellite telemetry. Patterns of behaviour recorded were rather unusual compared to other sea turtles in that dives were mainly deep, largely benthic and exceptionally long (>2 h) in some cases, characteristics typical of over-wintering turtles in colder environments. One individual occupied shallow coastal foraging zones, while the others foraged far from land (probably on the seabed) in relatively deep water (>100 m). Individuals performed long dives (frequently >100 min), but from the short post-dive intervals we suggest that these dives were mainly aerobic. Maximum dive depth recorded was 200 ± 20 m (mean maximum depths ranged from 20.1 to 46.7 m across individuals; n = 17328 dives in total; depths ≥3 m were considered ‘dives’) and the maximum duration was 200 ± 20 min (mean durations ranged from 24.5 to 48.0 min across individuals). Temperature profiles indicate that turtles experienced temperatures ranging from 23 to 29°C at the surface, with the lowest temperature recorded (18.7°C) at a depth of 98 m. Only 6.9% of the dives were in water <20°C. From time-allocation at depth (TAD) scores, we demonstrated that many dives reaching the known or inferred sea bottom were U-shaped, but there was no apparent diel signal in dive depth. This suggests that many benthic dives were not associated exclusively with resting behaviour and likely had a foraging component as well. The ability to perform long benthic dives allows this species to exploit deeper benthic environments in addition to the shallow coastal areas more generally occupied by adult hard-shelled sea turtles (e.g. green and hawksbill turtles). Deep benthic dives also occur in certain marine mammals (e.g. narwhals) and sea birds (e.g. rockhopper penguins) and therefore seem to be a general foraging strategy exploited by animals that can perform long dives.
History
Journal
Marine ecology progress seriesVolume
329Pagination
239 - 252Publisher
Inter-ResearchLocation
Oldendorf, GermanyPublisher DOI
ISSN
0171-8630eISSN
1616-1599Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2007, Inter-ResearchUsage metrics
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Keywords
aerobic metabolismBenthic divingforaging strategyhabitat selectionmovementNorthern Australiasatellite-relayed data loggerstemperature profilesScience & TechnologyLife Sciences & BiomedicinePhysical SciencesEcologyMarine & Freshwater BiologyOceanographyEnvironmental Sciences & EcologyFATTY-ACID-COMPOSITIONCENTRAL NORTH PACIFICSEA-TURTLESCARETTA-CARETTACHELONIA-MYDASGREEN TURTLESDERMOCHELYS-CORIACEAFORAGING BEHAVIORFEEDING ECOLOGYLEATHERBACK TURTLESZoologyOceanographyEcology
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