Fur seals do, but sea lions don't - cross taxa insights into exhalation during ascent from dives

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dc.contributor.authorHooker, S.K.
dc.contributor.authorAndrews, R.D.
dc.contributor.authorArnould, J.P.Y.
dc.contributor.authorBester, M.N.
dc.contributor.authorDavis, R.W.
dc.contributor.authorInsley, S.J.
dc.contributor.authorGales, N.J.
dc.contributor.authorGoldsworthy, S.D.
dc.contributor.authorMcKnight, J.C.
dc.date.issued2021
dc.description.abstractManagement of gases during diving is not well understood across marine mammal species. Prior to diving, phocid (true) seals generally exhale, a behaviour thought to assist with the prevention of decompression sickness. Otariid seals (fur seals and sea lions) have a greater reliance on their lung oxygen stores, and inhale prior to diving. One otariid, the Antarctic fur seal (<i>Arctocephalus gazella</i>), then exhales during the final 50-85% of the return to the surface, which may prevent another gas management issue: shallow-water blackout. Here, we compare data collected from animal-attached tags (video cameras, hydrophones and conductivity sensors) deployed on a suite of otariid seal species to examine the ubiquity of ascent exhalations for this group. We find evidence for ascent exhalations across four fur seal species, but that such exhalations are absent for three sea lion species. Fur seals and sea lions are no longer genetically separated into distinct subfamilies, but are morphologically distinguished by the thick underfur layer of fur seals. Together with their smaller size and energetic dives, we suggest their air-filled fur might underlie the need to perform these exhalations, although whether to reduce buoyancy and ascent speed, for the avoidance of shallow-water blackout or to prevent other cardiovascular management issues in their diving remains unclear. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.
dc.description.statementofresponsibilitySascha K. Hooker, Russel D. Andrews, John P. Y. Arnould, Marthán N. Bester, Randall W. Davis, Stephen J. Insley
dc.identifier.citationPhilosophical Transactions of the Royal Society of London. Biological Sciences, 2021; 376(1830):20200219-1-20200219-11
dc.identifier.doi10.1098/rstb.2020.0219
dc.identifier.issn0962-8436
dc.identifier.issn1471-2970
dc.identifier.urihttp://hdl.handle.net/2440/131726
dc.language.isoen
dc.publisherThe Royal Society
dc.relation.granthttp://purl.org/au-research/grants/arc/DP110102065
dc.rights© 2021 The Author(s) Published by the Royal Society. All rights reserved.
dc.source.urihttps://doi.org/10.1098/rstb.2020.0219
dc.subjectdiving physiology
dc.subjectgas management
dc.subjectotariid
dc.subjectshallow-water blackout
dc.titleFur seals do, but sea lions don't - cross taxa insights into exhalation during ascent from dives
dc.typeJournal article
pubs.publication-statusPublished

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