Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve
Are pelagic species such as sharks and tuna distributed homogenously or heterogeneously in the oceans? Large assemblages of these species have been observed at seamounts and offshore islands in the eastern tropical Pacific, which are considered hotspots of pelagic biodiversity. Is the species distri...
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Language: | English |
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ftcdlib:qt6bn0q249 2023-05-15T16:00:08+02:00 Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve Hearn, Alex Ketchum, James Klimley, A. Peter Espinoza, Eduardo Peñaherrera, Cesar pp 1899-1915 2010-09-01 application/pdf http://www.escholarship.org/uc/item/6bn0q249 english eng eScholarship, University of California http://www.escholarship.org/uc/item/6bn0q249 qt6bn0q249 public Hearn, Alex; Ketchum, James; Klimley, A. Peter; Espinoza, Eduardo; & Peñaherrera, Cesar. (2010). Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve. Marine Biology: International Journal on Life in Oceans and Coastal Waters, 157(9), pp 1899-1915. doi:10.1007/s00227-010-1460-2. Retrieved from: http://www.escholarship.org/uc/item/6bn0q249 Life Sciences Zoology Oceanography Biomedicine general Ecology Microbiology article 2010 ftcdlib https://doi.org/10.1007/s00227-010-1460-2 2016-04-02T18:51:02Z Are pelagic species such as sharks and tuna distributed homogenously or heterogeneously in the oceans? Large assemblages of these species have been observed at seamounts and offshore islands in the eastern tropical Pacific, which are considered hotspots of pelagic biodiversity. Is the species distribution uniform at these hotspots or do species aggregate at a finer spatial scale at these sites? We employed three techniques to demonstrate that the aggregations of scalloped hammerhead sharks, Sphyrna lewini, and other pelagic species were confined to the southeastern corner of Wolf Island in the Galapagos Marine Reserve. Coded ultrasonic transmitters were placed on individuals at this site and at another aggregation site at Darwin Island, separated from Wolf by 40 km, and they were detected by monitors moored at the southeastern corner of Wolf Island and rarely by monitors deployed at other sites around the island. Hammerhead sharks, carrying depth-sensing continual transmitters, were tracked for two-day periods in a vessel and shown to reside a disproportionately large fraction of their time at the southeastern corner. Visual censuses were carried out seasonally at the eight monitor sites at Wolf Island, recording the abundance of one species of tuna, four species of jacks, and a number of other species. The highest diversity and abundance of these species occurred in the southeastern corner of the island. Our results support the use of hammerhead sharks as indicator and umbrella species for pelagic hotspots on a fine scale. Article in Journal/Newspaper Darwin Island University of California: eScholarship Darwin Island ENVELOPE(-54.767,-54.767,-63.433,-63.433) Galapagos Pacific Marine Biology 157 9 1899 1915 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Life Sciences Zoology Oceanography Biomedicine general Ecology Microbiology |
spellingShingle |
Life Sciences Zoology Oceanography Biomedicine general Ecology Microbiology Hearn, Alex Ketchum, James Klimley, A. Peter Espinoza, Eduardo Peñaherrera, Cesar Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve |
topic_facet |
Life Sciences Zoology Oceanography Biomedicine general Ecology Microbiology |
description |
Are pelagic species such as sharks and tuna distributed homogenously or heterogeneously in the oceans? Large assemblages of these species have been observed at seamounts and offshore islands in the eastern tropical Pacific, which are considered hotspots of pelagic biodiversity. Is the species distribution uniform at these hotspots or do species aggregate at a finer spatial scale at these sites? We employed three techniques to demonstrate that the aggregations of scalloped hammerhead sharks, Sphyrna lewini, and other pelagic species were confined to the southeastern corner of Wolf Island in the Galapagos Marine Reserve. Coded ultrasonic transmitters were placed on individuals at this site and at another aggregation site at Darwin Island, separated from Wolf by 40 km, and they were detected by monitors moored at the southeastern corner of Wolf Island and rarely by monitors deployed at other sites around the island. Hammerhead sharks, carrying depth-sensing continual transmitters, were tracked for two-day periods in a vessel and shown to reside a disproportionately large fraction of their time at the southeastern corner. Visual censuses were carried out seasonally at the eight monitor sites at Wolf Island, recording the abundance of one species of tuna, four species of jacks, and a number of other species. The highest diversity and abundance of these species occurred in the southeastern corner of the island. Our results support the use of hammerhead sharks as indicator and umbrella species for pelagic hotspots on a fine scale. |
format |
Article in Journal/Newspaper |
author |
Hearn, Alex Ketchum, James Klimley, A. Peter Espinoza, Eduardo Peñaherrera, Cesar |
author_facet |
Hearn, Alex Ketchum, James Klimley, A. Peter Espinoza, Eduardo Peñaherrera, Cesar |
author_sort |
Hearn, Alex |
title |
Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve |
title_short |
Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve |
title_full |
Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve |
title_fullStr |
Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve |
title_full_unstemmed |
Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve |
title_sort |
hotspots within hotspots? hammerhead shark movements around wolf island, galapagos marine reserve |
publisher |
eScholarship, University of California |
publishDate |
2010 |
url |
http://www.escholarship.org/uc/item/6bn0q249 |
op_coverage |
pp 1899-1915 |
long_lat |
ENVELOPE(-54.767,-54.767,-63.433,-63.433) |
geographic |
Darwin Island Galapagos Pacific |
geographic_facet |
Darwin Island Galapagos Pacific |
genre |
Darwin Island |
genre_facet |
Darwin Island |
op_source |
Hearn, Alex; Ketchum, James; Klimley, A. Peter; Espinoza, Eduardo; & Peñaherrera, Cesar. (2010). Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve. Marine Biology: International Journal on Life in Oceans and Coastal Waters, 157(9), pp 1899-1915. doi:10.1007/s00227-010-1460-2. Retrieved from: http://www.escholarship.org/uc/item/6bn0q249 |
op_relation |
http://www.escholarship.org/uc/item/6bn0q249 qt6bn0q249 |
op_rights |
public |
op_doi |
https://doi.org/10.1007/s00227-010-1460-2 |
container_title |
Marine Biology |
container_volume |
157 |
container_issue |
9 |
container_start_page |
1899 |
op_container_end_page |
1915 |
_version_ |
1766396000724844544 |