Depth sets the recovery clock: evidence for a time-at-pressure effect in sea lions

All air-breathing marine vertebrates face the same fundamental trade-off: time spent foraging underwater must be offset by surface recovery between dives. For decades, the dominant view in diving physiology has been that post-dive duration (PDD) reflects the repayment of oxygen debt and clearance of carbon dioxide and lactate. Using more than 800 000 dives from five sea lion species across 18 colonies spanning tropical to subpolar waters, we quantified how PDD scales with dive depth and duration and evaluated whether this pattern is consistent with metabolic recovery interpretations or instead points to depth-linked constraints. We found that PDD increases primarily and linearly with depth, while dive duration contributes to PDD only at greater depths, a relationship conserved across species despite pronounced differences in body mass, dive physiology and foraging ecology. Our findings conflict with predictions of metabolic recovery interpretations and point to a pressure-linked mechanism in which time at depth and resulting inert-gas loading shape surface recovery. By highlighting pressure-linked inert-gas management as a central candidate mechanism for surface interval regulation in inhalation divers, our study revises a central assumption in diving physiology, with broad consequences for understanding foraging efficiency, habitat accessibility and vulnerability to environmental change in air-breathing marine vertebrates.

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Publication Details

Journal
Proceedings of the Royal Society B Biological Sciences
Published
2026-10-28
DOI
https://doi.org/10.1098/rspb.2026.1690
Primary Topic
Marine animal studies overview
Type
article
Field-Weighted Citation Impact
0.00

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article

Depth sets the recovery clock: evidence for a time-at-pressure effect in sea lions

Sharon R. Melin, Clive R. McMahon, Joseph Ivan Hoffman, Alastair M. M. Baylis et al.
1 links
Proceedings of the Royal Society B Biological Sciences
Marine animal studies overview
article

Depth sets the recovery clock: evidence for a time-at-pressure effect in sea lions

Sharon R. Melin, Clive R. McMahon, Joseph Ivan Hoffman, Alastair M. M. Baylis, Daniel Pereira da Costa, Jonas F. L. Schwarz, Luis A. Hückstädt, Stella Villegas‐Amtmann, B. Louise Chilvers, Shannon L. Fowler, Fritz Trillmich, Diego Páez‐Rosas, Rachel Rose Holser, Elizabeth A. McHuron, Simon David Goldsworthy, Carsten F. Dormann, Nathan Angelakis, Oliver Krüger, Svenja Stoehr, Robert Harcourt, Jana Jeglinski
article en

Abstract

All air-breathing marine vertebrates face the same fundamental trade-off: time spent foraging underwater must be offset by surface recovery between dives. For decades, the dominant view in diving physiology has been that post-dive duration (PDD) reflects the repayment of oxygen debt and clearance of carbon dioxide and lactate. Using more than 800 000 dives from five sea lion species across 18 colonies spanning tropical to subpolar waters, we quantified how PDD scales with dive depth and duration and evaluated whether this pattern is consistent with metabolic recovery interpretations or instead points to depth-linked constraints. We found that PDD increases primarily and linearly with depth, while dive duration contributes to PDD only at greater depths, a relationship conserved across species despite pronounced differences in body mass, dive physiology and foraging ecology. Our findings conflict with predictions of metabolic recovery interpretations and point to a pressure-linked mechanism in which time at depth and resulting inert-gas loading shape surface recovery. By highlighting pressure-linked inert-gas management as a central candidate mechanism for surface interval regulation in inhalation divers, our study revises a central assumption in diving physiology, with broad consequences for understanding foraging efficiency, habitat accessibility and vulnerability to environmental change in air-breathing marine vertebrates.

Proceedings of the Royal Society B Biological SciencesVol. 293(2081)
Charles Darwin Foundation (EC), British Antarctic Survey (GB), University of Freiburg (DE), University of California, Santa Cruz (US), Bielefeld University (DE), University of Washington (US), Aarhus University (DK), University of Exeter (GB), South Australian Research and Development Institute (AU), South Atlantic Environmental Research Institute (FK), NOAA National Marine Fisheries Service Alaska Fisheries Science Center (US), Sydney Institute of Marine Science (AU), Department of Conservation (NZ), Cooperative Institute for Climate, Ocean, & Ecosystem Studies (US), University of Khorfakkan (AE), Galapagos Science Center (EC), Massey University (NZ), The University of Adelaide (AU), Universidad San Francisco de Quito (EC), University of Glasgow (GB), Galapagos (Belgium) (BE), University of Roehampton (GB), Macquarie University (AU)
Deutsche Forschungsgemeinschaft
Life below water
Openalex Percentile: Top 17%
Marine animal studies overview
DOIOpen Access PDFOpenAlex
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