Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal
<jats:p>The duration of maternal foraging trips has been regarded as an indicator of foraging conditions in many marine mammals, including northern fur seals <jats:italic>Callorhinus ursinus</jats:italic> (NFS). However, previous work has focused on individual variation, was conduc...
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ftdukeunivdsp:oai:localhost:10161/23220 2023-11-12T04:15:20+01:00 Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal Merrill, GB Testa, JW Burns, JM 2021-05-26T18:38:41Z application/pdf https://hdl.handle.net/10161/23220 en eng Inter-Research Science Center Marine Ecology Progress Series 10.3354/meps13694 0171-8630 1616-1599 https://hdl.handle.net/10161/23220 Journal article 2021 ftdukeunivdsp 2023-10-17T09:44:29Z <jats:p>The duration of maternal foraging trips has been regarded as an indicator of foraging conditions in many marine mammals, including northern fur seals <jats:italic>Callorhinus ursinus</jats:italic> (NFS). However, previous work has focused on individual variation, was conducted during limited portions of the lactation period, and/or reached conclusions based on relatively small sample sizes. Here, we build upon the substantial foundations of this previous work to establish maternal foraging trip duration (MFTD) as an index of foraging success at the rookery level. We found that a 1 d increase in rookery-averaged MFTD corresponded to a 6.52% reduction in the average mass of female pups. Furthermore, rookery-averaged MFTD increased by 0.34 d per 1°C increase in average ocean bottom temperature. The magnitude of variation observed in both MFTD and pup mass is likely too small to help explain the general decline in population size seen over recent decades. However, the correlation between rookery-averaged MFTD and pup mass highlights the potential power of the MFTD index to detect bottom-up effects on pup growth, a likely indicator of survival. Furthermore, when compared with concurrently conducted studies on prey distribution, availability, and quality, the relationship between MFTD and bottom temperature suggests a northward shift in distribution of NFS preferred prey, walleye pollock <jats:italic>Gadus chalcogrammus</jats:italic>, that is associated with an increase in trip duration across the study period. Thus, rookery-averaged MFTD is a promising metric for tracking broad environmental changes, such as northerly shifts in the Eastern Bering Sea cold pool.</jats:p> Article in Journal/Newspaper Bering Sea Callorhinus ursinus Northern fur seal Duke University Libraries: DukeSpace Bering Sea |
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Open Polar |
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Duke University Libraries: DukeSpace |
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ftdukeunivdsp |
language |
English |
description |
<jats:p>The duration of maternal foraging trips has been regarded as an indicator of foraging conditions in many marine mammals, including northern fur seals <jats:italic>Callorhinus ursinus</jats:italic> (NFS). However, previous work has focused on individual variation, was conducted during limited portions of the lactation period, and/or reached conclusions based on relatively small sample sizes. Here, we build upon the substantial foundations of this previous work to establish maternal foraging trip duration (MFTD) as an index of foraging success at the rookery level. We found that a 1 d increase in rookery-averaged MFTD corresponded to a 6.52% reduction in the average mass of female pups. Furthermore, rookery-averaged MFTD increased by 0.34 d per 1°C increase in average ocean bottom temperature. The magnitude of variation observed in both MFTD and pup mass is likely too small to help explain the general decline in population size seen over recent decades. However, the correlation between rookery-averaged MFTD and pup mass highlights the potential power of the MFTD index to detect bottom-up effects on pup growth, a likely indicator of survival. Furthermore, when compared with concurrently conducted studies on prey distribution, availability, and quality, the relationship between MFTD and bottom temperature suggests a northward shift in distribution of NFS preferred prey, walleye pollock <jats:italic>Gadus chalcogrammus</jats:italic>, that is associated with an increase in trip duration across the study period. Thus, rookery-averaged MFTD is a promising metric for tracking broad environmental changes, such as northerly shifts in the Eastern Bering Sea cold pool.</jats:p> |
format |
Article in Journal/Newspaper |
author |
Merrill, GB Testa, JW Burns, JM |
spellingShingle |
Merrill, GB Testa, JW Burns, JM Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
author_facet |
Merrill, GB Testa, JW Burns, JM |
author_sort |
Merrill, GB |
title |
Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
title_short |
Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
title_full |
Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
title_fullStr |
Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
title_full_unstemmed |
Maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
title_sort |
maternal foraging trip duration as a population-level index of foraging and reproductive success for the northern fur seal |
publisher |
Inter-Research Science Center |
publishDate |
2021 |
url |
https://hdl.handle.net/10161/23220 |
geographic |
Bering Sea |
geographic_facet |
Bering Sea |
genre |
Bering Sea Callorhinus ursinus Northern fur seal |
genre_facet |
Bering Sea Callorhinus ursinus Northern fur seal |
op_relation |
Marine Ecology Progress Series 10.3354/meps13694 0171-8630 1616-1599 https://hdl.handle.net/10161/23220 |
_version_ |
1782332648914419712 |