Drift diving by hooded seals (Cystophora cristata) in the Northwest Atlantic Ocean
Many pinniped species perform a specific dive type, referred to as a 'drift dive', where they drift passively through the water column. This dive type has been suggested to function as a resting/sleeping or food processing dive, and can be used as an indication of feeding success by calcul...
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Published in | PloS one Vol. 9; no. 7; p. e103072 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Public Library of Science
22.07.2014
Public Library of Science (PLoS) |
Subjects | |
Online Access | Get full text |
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Summary: | Many pinniped species perform a specific dive type, referred to as a 'drift dive', where they drift passively through the water column. This dive type has been suggested to function as a resting/sleeping or food processing dive, and can be used as an indication of feeding success by calculating the daily change in vertical drift rates over time, which reflects the relative fluctuations in buoyancy of the animal as the proportion of lipids in the body change. Northwest Atlantic hooded seals perform drift dives at regular intervals throughout their annual migration across the Northwest Atlantic Ocean. We found that the daily change in drift rate varied with geographic location and the time of year and that this differed between sexes. Positive changes in buoyancy (reflecting increased lipid stores) were evident throughout their migration range and although overlapping somewhat, they were not statistically associated with high use areas as indicated by First Passage Time (FPT). Differences in the seasonal fluctuations of buoyancy between males and females suggest that they experience a difference in patterns of energy gain and loss during winter and spring, associated with breeding. The fluctuations in buoyancy around the moulting period were similar between sexes. |
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Bibliography: | Conceived and designed the experiments: JMA GBS YW MOH ARA MSM LB. Performed the experiments: GBS MOH ARA. Analyzed the data: JMA LB MSM. Contributed reagents/materials/analysis tools: MSM LB YW GBS JMA. Wrote the paper: JMA YW GBS LB. Obtained funding: GBS ARA. Competing Interests: The authors have declared that no competing interests exist. |
ISSN: | 1932-6203 1932-6203 |
DOI: | 10.1371/journal.pone.0103072 |