A new method to quantify within dive foraging behaviour in marine predators.
Studies on diving behaviour classically divide a dive into three phases: the descent, bottom and ascent phases, with foraging assumed to occur during the bottom phase. The greater complexity of dive revealed through modern, high resolution data highlights the need to re-assess this approach and to c...
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ftdoajarticles:oai:doaj.org/article:fb64fd216765466e92a81f938785b5ca 2023-05-15T16:05:45+02:00 A new method to quantify within dive foraging behaviour in marine predators. Karine Heerah Mark Hindell Christophe Guinet Jean-Benoît Charrassin 2014-01-01T00:00:00Z https://doi.org/10.1371/journal.pone.0099329 https://doaj.org/article/fb64fd216765466e92a81f938785b5ca EN eng Public Library of Science (PLoS) http://europepmc.org/articles/PMC4055756?pdf=render https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0099329 https://doaj.org/article/fb64fd216765466e92a81f938785b5ca PLoS ONE, Vol 9, Iss 6, p e99329 (2014) Medicine R Science Q article 2014 ftdoajarticles https://doi.org/10.1371/journal.pone.0099329 2022-12-31T12:41:24Z Studies on diving behaviour classically divide a dive into three phases: the descent, bottom and ascent phases, with foraging assumed to occur during the bottom phase. The greater complexity of dive revealed through modern, high resolution data highlights the need to re-assess this approach and to consider a larger number of phases within individual dives. Two southern elephant seals (SES) were fitted with a head mounted Time Depth Recorder (TDR) and an accelerometer from which prey capture attempts were estimated. A Weddell seal was also fitted with a TDR. TDRs for both species recorded depth once per second. We quantified the within dive behaviour using an automated broken stick algorithm identifying the optimal number of segments within each dive. The vertical sinuosity of the segments was used to infer two types of behaviours, with highly sinuous segments indicating "hunting" and less sinuous segments indicating "transiting". Using the broken stick method the seals alternated between "hunting" and "transit" modes with an average of 6±2 and 7±0.02 behavioural phases within each dive for the Weddell seal and SES, respectively. In SES, 77% of prey capture attempts (identified from the acceleration data) occurred in highly sinuous phases ("hunting") as defined by our new approach. SES spent more time in transit mode within a dive, and hunting mostly occurred during the bottom phase. Conversely the Weddell seal spent more time in hunting mode which also occurred during bottom phase but occurred mostly at shallower depths. Such differences probably reflect different foraging tactics and habitat use. For both species, hunting time differs significantly from bottom time previously used as a proxy for the time spent foraging in a dive. The hunting time defined by our method therefore provides a more accurate fine-scale description of the seals' foraging behaviour. Article in Journal/Newspaper Elephant Seals Southern Elephant Seals Weddell Seal Directory of Open Access Journals: DOAJ Articles Weddell PLoS ONE 9 6 e99329 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Medicine R Science Q |
spellingShingle |
Medicine R Science Q Karine Heerah Mark Hindell Christophe Guinet Jean-Benoît Charrassin A new method to quantify within dive foraging behaviour in marine predators. |
topic_facet |
Medicine R Science Q |
description |
Studies on diving behaviour classically divide a dive into three phases: the descent, bottom and ascent phases, with foraging assumed to occur during the bottom phase. The greater complexity of dive revealed through modern, high resolution data highlights the need to re-assess this approach and to consider a larger number of phases within individual dives. Two southern elephant seals (SES) were fitted with a head mounted Time Depth Recorder (TDR) and an accelerometer from which prey capture attempts were estimated. A Weddell seal was also fitted with a TDR. TDRs for both species recorded depth once per second. We quantified the within dive behaviour using an automated broken stick algorithm identifying the optimal number of segments within each dive. The vertical sinuosity of the segments was used to infer two types of behaviours, with highly sinuous segments indicating "hunting" and less sinuous segments indicating "transiting". Using the broken stick method the seals alternated between "hunting" and "transit" modes with an average of 6±2 and 7±0.02 behavioural phases within each dive for the Weddell seal and SES, respectively. In SES, 77% of prey capture attempts (identified from the acceleration data) occurred in highly sinuous phases ("hunting") as defined by our new approach. SES spent more time in transit mode within a dive, and hunting mostly occurred during the bottom phase. Conversely the Weddell seal spent more time in hunting mode which also occurred during bottom phase but occurred mostly at shallower depths. Such differences probably reflect different foraging tactics and habitat use. For both species, hunting time differs significantly from bottom time previously used as a proxy for the time spent foraging in a dive. The hunting time defined by our method therefore provides a more accurate fine-scale description of the seals' foraging behaviour. |
format |
Article in Journal/Newspaper |
author |
Karine Heerah Mark Hindell Christophe Guinet Jean-Benoît Charrassin |
author_facet |
Karine Heerah Mark Hindell Christophe Guinet Jean-Benoît Charrassin |
author_sort |
Karine Heerah |
title |
A new method to quantify within dive foraging behaviour in marine predators. |
title_short |
A new method to quantify within dive foraging behaviour in marine predators. |
title_full |
A new method to quantify within dive foraging behaviour in marine predators. |
title_fullStr |
A new method to quantify within dive foraging behaviour in marine predators. |
title_full_unstemmed |
A new method to quantify within dive foraging behaviour in marine predators. |
title_sort |
new method to quantify within dive foraging behaviour in marine predators. |
publisher |
Public Library of Science (PLoS) |
publishDate |
2014 |
url |
https://doi.org/10.1371/journal.pone.0099329 https://doaj.org/article/fb64fd216765466e92a81f938785b5ca |
geographic |
Weddell |
geographic_facet |
Weddell |
genre |
Elephant Seals Southern Elephant Seals Weddell Seal |
genre_facet |
Elephant Seals Southern Elephant Seals Weddell Seal |
op_source |
PLoS ONE, Vol 9, Iss 6, p e99329 (2014) |
op_relation |
http://europepmc.org/articles/PMC4055756?pdf=render https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0099329 https://doaj.org/article/fb64fd216765466e92a81f938785b5ca |
op_doi |
https://doi.org/10.1371/journal.pone.0099329 |
container_title |
PLoS ONE |
container_volume |
9 |
container_issue |
6 |
container_start_page |
e99329 |
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1766401644878102528 |