Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris.
Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota-poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknow...
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ftcdlib:oai:escholarship.org/ark:/13030/qt5fp7n5tg 2023-05-15T16:05:24+02:00 Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. Naito, Yasuhiko Costa, Daniel P Adachi, Taiki Robinson, Patrick W Peterson, Sarah H Mitani, Yoko Takahashi, Akinori 6259 - 6270 2017-08-01 application/pdf https://escholarship.org/uc/item/5fp7n5tg unknown eScholarship, University of California qt5fp7n5tg https://escholarship.org/uc/item/5fp7n5tg public Ecology and evolution, vol 7, iss 16 bio‐logging elephant seal feeding efficiency jaw‐motion recorder marine mammal oxygen minimum zone bio-logging jaw-motion recorder Ecology Evolutionary Biology article 2017 ftcdlib 2021-01-24T17:37:58Z Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota-poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknown. Assessment of their feeding rate is the key to understanding their foraging behavior, but this has been challenging. Here, we assessed the feeding rate of 14 female northern elephant seals determined by jaw motion events (JME) and dive cycle time to examine how feeding rates varied with dive depth, particularly in the OMZ. We also obtained video footage from seal-mounted videos to understand their feeding in the OMZ. While the diel vertical migration pattern was apparent for most depths of the JME, some very deep dives, beyond the normal diel depth ranges, occurred episodically during daylight hours. The midmesopelagic zone was the main foraging zone for all seals. Larger seals tended to show smaller numbers of JME and lower feeding rates than smaller seals during migration, suggesting that larger seals tended to feed on larger prey to satisfy their metabolic needs. Larger seals also dived frequently to the deep OMZ, possibly because of a greater diving ability than smaller seals, suggesting their dependency on food in the deeper depth zones. Video observations showed that seals encountered the rarely reported ragfish (Icosteus aenigmaticus) in the depths of the OMZ, which failed to show an escape response from the seals, suggesting that low oxygen concentrations might reduce prey mobility. Less mobile prey in OMZ would enhance the efficiency of foraging in this zone, especially for large seals that can dive deeper and longer. We suggest that the OMZ plays an important role in structuring the mesopelagic ecosystem and for the survival and evolution of elephant seals. Article in Journal/Newspaper Elephant Seal Elephant Seals University of California: eScholarship |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
bio‐logging elephant seal feeding efficiency jaw‐motion recorder marine mammal oxygen minimum zone bio-logging jaw-motion recorder Ecology Evolutionary Biology |
spellingShingle |
bio‐logging elephant seal feeding efficiency jaw‐motion recorder marine mammal oxygen minimum zone bio-logging jaw-motion recorder Ecology Evolutionary Biology Naito, Yasuhiko Costa, Daniel P Adachi, Taiki Robinson, Patrick W Peterson, Sarah H Mitani, Yoko Takahashi, Akinori Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. |
topic_facet |
bio‐logging elephant seal feeding efficiency jaw‐motion recorder marine mammal oxygen minimum zone bio-logging jaw-motion recorder Ecology Evolutionary Biology |
description |
Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota-poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknown. Assessment of their feeding rate is the key to understanding their foraging behavior, but this has been challenging. Here, we assessed the feeding rate of 14 female northern elephant seals determined by jaw motion events (JME) and dive cycle time to examine how feeding rates varied with dive depth, particularly in the OMZ. We also obtained video footage from seal-mounted videos to understand their feeding in the OMZ. While the diel vertical migration pattern was apparent for most depths of the JME, some very deep dives, beyond the normal diel depth ranges, occurred episodically during daylight hours. The midmesopelagic zone was the main foraging zone for all seals. Larger seals tended to show smaller numbers of JME and lower feeding rates than smaller seals during migration, suggesting that larger seals tended to feed on larger prey to satisfy their metabolic needs. Larger seals also dived frequently to the deep OMZ, possibly because of a greater diving ability than smaller seals, suggesting their dependency on food in the deeper depth zones. Video observations showed that seals encountered the rarely reported ragfish (Icosteus aenigmaticus) in the depths of the OMZ, which failed to show an escape response from the seals, suggesting that low oxygen concentrations might reduce prey mobility. Less mobile prey in OMZ would enhance the efficiency of foraging in this zone, especially for large seals that can dive deeper and longer. We suggest that the OMZ plays an important role in structuring the mesopelagic ecosystem and for the survival and evolution of elephant seals. |
format |
Article in Journal/Newspaper |
author |
Naito, Yasuhiko Costa, Daniel P Adachi, Taiki Robinson, Patrick W Peterson, Sarah H Mitani, Yoko Takahashi, Akinori |
author_facet |
Naito, Yasuhiko Costa, Daniel P Adachi, Taiki Robinson, Patrick W Peterson, Sarah H Mitani, Yoko Takahashi, Akinori |
author_sort |
Naito, Yasuhiko |
title |
Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. |
title_short |
Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. |
title_full |
Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. |
title_fullStr |
Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. |
title_full_unstemmed |
Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris. |
title_sort |
oxygen minimum zone: an important oceanographic habitat for deep-diving northern elephant seals, mirounga angustirostris. |
publisher |
eScholarship, University of California |
publishDate |
2017 |
url |
https://escholarship.org/uc/item/5fp7n5tg |
op_coverage |
6259 - 6270 |
genre |
Elephant Seal Elephant Seals |
genre_facet |
Elephant Seal Elephant Seals |
op_source |
Ecology and evolution, vol 7, iss 16 |
op_relation |
qt5fp7n5tg https://escholarship.org/uc/item/5fp7n5tg |
op_rights |
public |
_version_ |
1766401302978363392 |