Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles
Ascension Island in the South Atlantic Ocean is renowned for its globally-important nesting population of green turtles ( Chelonia mydas ) that has been the subject of long-term research. By comparison, very little is known about the apparently small population of hawksbill turtles ( Eretmochelys im...
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crcambridgeupr:10.1017/s0025315414001258 2024-03-03T08:48:48+00:00 Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles Weber, Sam B. Weber, Nicola Godley, Brendan J. Pelembe, Tara Stroud, Stedson Williams, Natasha Broderick, Annette C. 2014 http://dx.doi.org/10.1017/s0025315414001258 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315414001258 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Journal of the Marine Biological Association of the United Kingdom volume 97, issue 4, page 813-820 ISSN 0025-3154 1469-7769 Aquatic Science journal-article 2014 crcambridgeupr https://doi.org/10.1017/s0025315414001258 2024-02-08T08:40:40Z Ascension Island in the South Atlantic Ocean is renowned for its globally-important nesting population of green turtles ( Chelonia mydas ) that has been the subject of long-term research. By comparison, very little is known about the apparently small population of hawksbill turtles ( Eretmochelys imbricata ) that have been recorded in its waters, thousands of kilometres from known nesting beaches. Here, we collate 10 years of in-water tagging data, opportunistic public sighting records and underwater observations to provide a baseline for future research, and present preliminary data on habitat use derived from two individuals fitted with GPS transmitters. Although public sightings were inevitably biased towards popular recreation areas, the resulting distribution suggests that hawksbill turtles occur year round in Ascension Island's waters along the entire 65 km of coastline. Hawksbills were observed feeding on benthic algae and encrusting sponges, and were frequently seen scavenging on fish discards around the Island's pier at night aided by anthropogenic lighting. Between 2003 and 2013, 35 turtles were captured, measured, tagged and then released. Curved carapace lengths ranged from 33.5 to 85 cm (mean = 48.8 cm) indicating that most (if not all) individuals encountered around Ascension are post-pelagic juveniles. Four individuals were recaptured at least once giving a mean minimum residence time of 4.2 yr (range: 2.8–7.3 yr) and a mean growth rate of 2.8 cm yr −1 . Turtles fitted with Fastloc™ GPS devices remained at Ascension Island for the duration of the study (>90 days) and occupied restricted home ranges with an average area of 2.5 km 2 and an average ‘core use area’ (50% utilization distribution) of 0.05 km 2 . Together, these results suggest that Ascension Island serves as a mid-Atlantic developmental habitat for benthic-feeding, juvenile hawksbill turtles on extended oceanic migrations before recruiting to their adult foraging grounds, likely to be located in Brazil or tropical West Africa. Article in Journal/Newspaper South Atlantic Ocean Cambridge University Press Journal of the Marine Biological Association of the United Kingdom 97 4 813 820 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Aquatic Science |
spellingShingle |
Aquatic Science Weber, Sam B. Weber, Nicola Godley, Brendan J. Pelembe, Tara Stroud, Stedson Williams, Natasha Broderick, Annette C. Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles |
topic_facet |
Aquatic Science |
description |
Ascension Island in the South Atlantic Ocean is renowned for its globally-important nesting population of green turtles ( Chelonia mydas ) that has been the subject of long-term research. By comparison, very little is known about the apparently small population of hawksbill turtles ( Eretmochelys imbricata ) that have been recorded in its waters, thousands of kilometres from known nesting beaches. Here, we collate 10 years of in-water tagging data, opportunistic public sighting records and underwater observations to provide a baseline for future research, and present preliminary data on habitat use derived from two individuals fitted with GPS transmitters. Although public sightings were inevitably biased towards popular recreation areas, the resulting distribution suggests that hawksbill turtles occur year round in Ascension Island's waters along the entire 65 km of coastline. Hawksbills were observed feeding on benthic algae and encrusting sponges, and were frequently seen scavenging on fish discards around the Island's pier at night aided by anthropogenic lighting. Between 2003 and 2013, 35 turtles were captured, measured, tagged and then released. Curved carapace lengths ranged from 33.5 to 85 cm (mean = 48.8 cm) indicating that most (if not all) individuals encountered around Ascension are post-pelagic juveniles. Four individuals were recaptured at least once giving a mean minimum residence time of 4.2 yr (range: 2.8–7.3 yr) and a mean growth rate of 2.8 cm yr −1 . Turtles fitted with Fastloc™ GPS devices remained at Ascension Island for the duration of the study (>90 days) and occupied restricted home ranges with an average area of 2.5 km 2 and an average ‘core use area’ (50% utilization distribution) of 0.05 km 2 . Together, these results suggest that Ascension Island serves as a mid-Atlantic developmental habitat for benthic-feeding, juvenile hawksbill turtles on extended oceanic migrations before recruiting to their adult foraging grounds, likely to be located in Brazil or tropical West Africa. |
format |
Article in Journal/Newspaper |
author |
Weber, Sam B. Weber, Nicola Godley, Brendan J. Pelembe, Tara Stroud, Stedson Williams, Natasha Broderick, Annette C. |
author_facet |
Weber, Sam B. Weber, Nicola Godley, Brendan J. Pelembe, Tara Stroud, Stedson Williams, Natasha Broderick, Annette C. |
author_sort |
Weber, Sam B. |
title |
Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles |
title_short |
Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles |
title_full |
Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles |
title_fullStr |
Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles |
title_full_unstemmed |
Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles |
title_sort |
ascension island as a mid-atlantic developmental habitat for juvenile hawksbill turtles |
publisher |
Cambridge University Press (CUP) |
publishDate |
2014 |
url |
http://dx.doi.org/10.1017/s0025315414001258 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315414001258 |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
Journal of the Marine Biological Association of the United Kingdom volume 97, issue 4, page 813-820 ISSN 0025-3154 1469-7769 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0025315414001258 |
container_title |
Journal of the Marine Biological Association of the United Kingdom |
container_volume |
97 |
container_issue |
4 |
container_start_page |
813 |
op_container_end_page |
820 |
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1792505821758750720 |