[MARMAM] New publication on swimming gaits in beaked whales (Lucía Martina Martín López)

Lucia Martina Martin Lopez lmml2 at st-andrews.ac.uk
Thu May 14 00:52:42 PDT 2015


Dear MARMAM colleagues,

We are pleased to announce a new publication in which we described a
new method for estimating the biomechanical parameters of swimming
strokes from tag data. This study reveals that beaked whales may increase
  efficiency by switching gaits during different phases of deep dives.

Martı́n López, L. M., Miller, P., Aguilar de Soto, N. and Johnson, M.
(2015). Gait switches in deepdiving
beaked whales: biomechanical strategies for long-duration dives. J.
Exp. Biol. 218, 1325-1338.


*Abstract*
Diving animals modulate their swimming gaits to promote locomotor
efficiency and so enable longer, more productive dives. Beaked whales
perform extremely long and deep foraging dives that probably exceed
aerobic capacities for some species. Here, we use biomechanical data
from suction-cup tags attached to three species of beaked whales
(Mesoplodon densirostris, N=10; Ziphius cavirostris, N=9; and
Hyperoodon ampullatus, N=2) to characterize their swimming gaits. In
addition to continuous stroking and strokeand- glide gaits described
for other diving mammals, all whales produced occasional fluke-strokes
with distinctly larger dorsoventral acceleration, which we termed
‘type-B’ strokes. These high-power strokes occurred almost exclusively
during deep dive ascents as part of a novel mixed gait. To quantify
body rotations and specific acceleration generated during strokes we
adapted a kinematic method combining data from two sensors in the tag.
Body rotations estimated with high-rate magnetometer data were
subtracted from accelerometer data to estimate the resulting surge and
heave accelerations. Using this method, we show that stroke duration,
rotation angle and acceleration were bi-modal for these species, with
B-strokes having 76%of the duration, 52%larger body rotation and four
times more surge than normal strokes.  The additional acceleration of
B-strokes did not lead to faster ascents, but rather enabled brief
glides, which may improve the overall efficiency of this gait. Their
occurrence towards the end of long dives leads us to propose that
B-strokes may recruit fast-twitch fibres that comprise ∼80% of
swimming muscles in Blainville’s beaked whales, thus prolonging
foraging time at depth.


The article can be found at:
http://jeb.biologists.org/content/218/9/1325.abstract

Please contact for a PDF at:
lmml2 at st-andrews.ac.uk

Kind regards,

-- 
Lucía Martina Martín López,
PhD student
Sea Mammal Research Unit
Scottish Oceans Institute
University of St Andrews
KY16 8LB, Fife
Scotland, UK
lmml2 at st-andrews.ac.uk
http://soundtags.st-andrews.ac.uk/people/lucia-martin-lopez/

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