SealSonification_v0.1.wav (1.07 GB)
SealSonification_v0.1
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posted on 2018-04-05, 07:16 authored by Carlos M Duarte, Paul Riker, Madhusudhanan Srinivasan, Patrick W Robinson, Juan Pablo Gallo-Reynoso, Daniel P CostaUnderstanding movement of
marine megafauna across the ocean is largely based on approaches and models
based on analysis of tracks of single animals.
While this has led to major progress, the possibility of concerted group
dynamics has not been sufficiently examined, possibly due to challenges in
exploring massive amounts of data required to this end. Here we report a sonification experiment,
where the collective movement of northern elephant seals (Mirounga angustirostris) was explored by coding their group
dynamics into sound. Specifically, we
converted into sound data derived from a tagging program involving a total of
321 tagged animals tracked over a decade, between 20 February 2004 and 30 May
2014, consisting of an observation period of 90063 hours, composed of 1,027,839
individual positions. The data
parameters used to provide the sound are position (longitude) and spread
(degree of displacement taken for the active group). These data parameters are mapped to the sonic
parameters of frequency (pitch) and amplitude (volume), respectively. Examination of the resulting sound revealed
features of motion that translate into specific patterns in space. The serial
departure of elephant seals to initiate their trips into waves is clearly
reflected in the addition of tonalities, with coherent swimming of the animals
conforming a wave reflected in the modulated fluctuations in volume, suggesting
coordinated fluctuations in dispersion of the wave. Smooth changes in volume,
coordinated with pitch variability, indicate that the animals spread out as
they move further away from the colony, with one or a few animals exploring an
ocean area away from that explored by the core wave. The shift in volume and pitch also signals at
group coordination in initiating the return home. Coordinated initiation of the
return to the colony is also clearly revealed by the sonification, as reflected
in an increase in volume and pitch of the notes denoting the movement of each
animal in a migration wave. This sonification reveals clear patterns of covariation
in movement data, which drivers and triggers, whether intrinsic or
environental, cannot be elucidated here but allow to formulate a number of
non-trivial questions on the synchronized nature of group behavior of northern
elephant seals foraging across the NE Pacific Ocean.