Proxies of energy expenditure for marine mammals: an experimental test of "the time trap"

Monique A. Ladds*, David A. S. Rosen, David J. Slip, Robert G. Harcourt

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)
23 Downloads (Pure)


Direct measures of energy expenditure are difficult to obtain in marine mammals, and accelerometry may be a useful proxy. Recently its utility has been questioned as some analyses derived their measure of activity level by calculating the sum of accelerometry-based values and then comparing this summation to summed (total) energy expenditure (the so-called time trap). To test this hypothesis, we measured oxygen consumption of captive fur seals and sea lions wearing accelerometers during submerged swimming and calculated total and rate of energy expenditure. We compared these values with two potential proxies of energy expenditure derived from accelerometry data: flipper strokes and dynamic body acceleration (DBA). Total number of strokes, total DBA, and submergence time all predicted total oxygen consumption (sVO2 ml kg-1). However, both total DBA and total number of strokes were correlated with submergence time. Neither stroke rate nor mean DBA could predict the rate of oxygen consumption ( Vs O2 ml min-1 kg-1). The relationship of total DBA and total strokes with total oxygen consumption is apparently a result of introducing a constant (time) into both sides of the relationship. This experimental evidence supports the conclusion that proxies derived from accelerometers cannot estimate the energy expenditure of marine mammals.

Original languageEnglish
Article number11815
Pages (from-to)1-10
Number of pages10
JournalScientific Reports
Issue number1
Publication statusPublished - 18 Sep 2017

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Copyright the Author(s) 2017. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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