In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies
Predators are thought to reduce travel speed and increase turning rate in areas where resources are relatively more abundant, a behavior termed “area-restricted search.” However, evidence for this is rare, and few empirical data exist for large predators. Animals exhibiting foraging site fidelity co...
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ftdatacite:10.6084/m9.figshare.c.3303996 2023-05-15T13:53:19+02:00 In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies Thums, Michele Bradshaw, Corey J. A. Hindell, Mark A. 2016 https://dx.doi.org/10.6084/m9.figshare.c.3303996 https://figshare.com/collections/In_situ_measures_of_foraging_success_and_prey_encounter_reveal_marine_habitat-dependent_search_strategies/3303996 unknown Figshare https://dx.doi.org/10.1890/09-1299.1 CC-BY http://creativecommons.org/licenses/by/3.0/us CC-BY Environmental Science Ecology FOS Biological sciences Collection article 2016 ftdatacite https://doi.org/10.6084/m9.figshare.c.3303996 https://doi.org/10.1890/09-1299.1 2021-11-05T12:55:41Z Predators are thought to reduce travel speed and increase turning rate in areas where resources are relatively more abundant, a behavior termed “area-restricted search.” However, evidence for this is rare, and few empirical data exist for large predators. Animals exhibiting foraging site fidelity could also be spatially aware of suitable feeding areas based on prior experience; changes in movement patterns might therefore arise from the anticipation of higher prey density. We tested the hypothesis that regions of area-restricted search were associated with a higher number of daily speed spikes (a proxy for potential prey encounter rate) and foraging success in southern elephant seals ( Mirounga leonina ), a species exhibiting both area-restricted searches and high interannual foraging site fidelity. We used onshore morphological measurements and diving data from archival tags deployed during winter foraging trips. Foraging success was inferred from in situ changes in relative lipid content derived from measured changes in buoyancy, and first-passage time analysis was used to identify area-restricted search behavior. Seals exhibited relatively direct southerly movement on average, with intensive search behavior predominantly located at the distal end of tracks. The probability of being in search mode was positively related to changes in relative lipid content; thus, intensively searched areas were associated with the highest foraging success. However, there was high foraging success during the outward transit even though seals moved through quickly without slowing down and increasing turning rate to exploit these areas. In addition, the probability of being in search mode was negatively related to the number of daily speed spikes. These results suggest that movement patterns represent a response to prior expectation of the location of predictable and profitable resources. Shelf habitat was 4–9 times more profitable than the other habitats, emphasizing the importance of the East Antarctic shelf for this and other predators in the region. We have provided rare empirical data with which to investigate the relationship between predator foraging strategy and prey encounter/foraging success, underlining the importance of inferring the timing and spatial arrangement of successful food acquisition for interpreting foraging strategies correctly. Article in Journal/Newspaper Antarc* Antarctic Elephant Seals Mirounga leonina Southern Elephant Seals DataCite Metadata Store (German National Library of Science and Technology) Antarctic |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Environmental Science Ecology FOS Biological sciences |
spellingShingle |
Environmental Science Ecology FOS Biological sciences Thums, Michele Bradshaw, Corey J. A. Hindell, Mark A. In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
topic_facet |
Environmental Science Ecology FOS Biological sciences |
description |
Predators are thought to reduce travel speed and increase turning rate in areas where resources are relatively more abundant, a behavior termed “area-restricted search.” However, evidence for this is rare, and few empirical data exist for large predators. Animals exhibiting foraging site fidelity could also be spatially aware of suitable feeding areas based on prior experience; changes in movement patterns might therefore arise from the anticipation of higher prey density. We tested the hypothesis that regions of area-restricted search were associated with a higher number of daily speed spikes (a proxy for potential prey encounter rate) and foraging success in southern elephant seals ( Mirounga leonina ), a species exhibiting both area-restricted searches and high interannual foraging site fidelity. We used onshore morphological measurements and diving data from archival tags deployed during winter foraging trips. Foraging success was inferred from in situ changes in relative lipid content derived from measured changes in buoyancy, and first-passage time analysis was used to identify area-restricted search behavior. Seals exhibited relatively direct southerly movement on average, with intensive search behavior predominantly located at the distal end of tracks. The probability of being in search mode was positively related to changes in relative lipid content; thus, intensively searched areas were associated with the highest foraging success. However, there was high foraging success during the outward transit even though seals moved through quickly without slowing down and increasing turning rate to exploit these areas. In addition, the probability of being in search mode was negatively related to the number of daily speed spikes. These results suggest that movement patterns represent a response to prior expectation of the location of predictable and profitable resources. Shelf habitat was 4–9 times more profitable than the other habitats, emphasizing the importance of the East Antarctic shelf for this and other predators in the region. We have provided rare empirical data with which to investigate the relationship between predator foraging strategy and prey encounter/foraging success, underlining the importance of inferring the timing and spatial arrangement of successful food acquisition for interpreting foraging strategies correctly. |
format |
Article in Journal/Newspaper |
author |
Thums, Michele Bradshaw, Corey J. A. Hindell, Mark A. |
author_facet |
Thums, Michele Bradshaw, Corey J. A. Hindell, Mark A. |
author_sort |
Thums, Michele |
title |
In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
title_short |
In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
title_full |
In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
title_fullStr |
In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
title_full_unstemmed |
In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
title_sort |
in situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies |
publisher |
Figshare |
publishDate |
2016 |
url |
https://dx.doi.org/10.6084/m9.figshare.c.3303996 https://figshare.com/collections/In_situ_measures_of_foraging_success_and_prey_encounter_reveal_marine_habitat-dependent_search_strategies/3303996 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Elephant Seals Mirounga leonina Southern Elephant Seals |
genre_facet |
Antarc* Antarctic Elephant Seals Mirounga leonina Southern Elephant Seals |
op_relation |
https://dx.doi.org/10.1890/09-1299.1 |
op_rights |
CC-BY http://creativecommons.org/licenses/by/3.0/us |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.6084/m9.figshare.c.3303996 https://doi.org/10.1890/09-1299.1 |
_version_ |
1766258355552124928 |