Dear colleagues,
I am pleased to announce the publication of a new paper in Scientific
Reports entitled : 'Flipper strokes can predict energy expenditure and
locomotion costs in free-ranging northern and Antarctic fur seals'.
Abstract:
Flipper strokes have been proposed as proxies to estimate the energy
expended by marine vertebrates
while foraging at sea, but this has never been validated on free-ranging
otariids (fur seals and sea lions).
Our goal was to investigate how well flipper strokes correlate with
energy expenditure in 33 foraging
northern and Antarctic fur seals equipped with accelerometers, GPS, and
time-depth recorders. We
concomitantly measured field metabolic rates with the doubly-labelled
water method and derived
activity-specific energy expenditures using fine-scale time-activity
budgets for each seal. Flipper strokes
were detected while diving or surface transiting using dynamic
acceleration. Despite some inter-species
differences in flipper stroke dynamics or frequencies, both species of
fur seals spent 3.79 ± 0.39 J/kg per
stroke and had a cost of transport of ~1.6–1.9 J/kg/m while diving.
Also, flipper stroke counts were good
predictors of energy spent while diving (R2 = 0.76) and to a lesser
extent while transiting (R2 = 0.63).
However, flipper stroke count was a poor predictor overall of total
energy spent during a full foraging
trip (R2 = 0.50). Amplitude of flipper strokes (i.e., acceleration
amplitude × number of strokes) predicted
total energy expenditure (R2 = 0.63) better than flipper stroke counts,
but was not as accurate as other
acceleration-based proxies, i.e. Overall Dynamic Body Acceleration.
This article is available at: http://www.nature.com/articles/srep33912
Best wishes,
Tiphaine Jeanniard du Dot, PhD
--
Tiphaine Jeanniard-du-Dot, PhD
Marine Mammal Research Unit
2202 Main Mall, AERL bldg
University of British Columbia
Vancouver, BC, V6T1Z4, CANADA
Tel:+1-604-822-9150 / cell:+1-604-724-4230
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