All,
My co-authors and I are pleased to announce the publication of the following article:
Quick, N. J., Isojunno, S, Sadykova, D, Bowers, M, Nowacek, D. and Read A. Hidden Markov models reveal complexity in the diving behaviour of short-finned pilot whales. Sci. Rep. 7, 45765; doi: 10.1038/srep45765 (2017).
Diving behaviour of short-finned pilot whales is often described by two states; deep foraging and shallow, non-foraging dives. However, this simple classification system ignores much of the variation that occurs during subsurface periods.
We used multi-state hidden Markov models (HMM) to characterize states of diving behaviour and the transitions between states in short-finned pilot whales. We used three parameters (number of buzzes, maximum dive depth and duration) measured in 259 dives by
digital acoustic recording tags (DTAGs) deployed on 20 individual whales off Cape Hatteras, North Carolina, USA. The HMM identified a four-state model as the best descriptor of diving behaviour. The state-dependent distributions for the diving parameters showed
variation between states, indicative of different diving behaviours. Transition probabilities were considerably higher for state persistence than state switching, indicating that dive types occurred in bouts. Our results indicate that subsurface behaviour
in short-finned pilot whales is more complex than a simple dichotomy of deep and shallow diving states, and labelling all subsurface behaviour as deep dives or shallow dives discounts a significant amount of important variation. We discuss potential drivers
of these patterns, including variation in foraging success, prey availability and selection, bathymetry, physiological constraints and socially mediated behaviour.
The publication is open access and available at
www.nature.com/articles/srep45765
Kind Regards
Nicola
Dr Nicola J. Quick
Research Scientist
Nicholas School of the Environment
Duke Marine Lab
135 Duke Marine Lab Road
Beaufort
NC 28516
https://scholars.duke.edu/person/nicola.quick
Honorary Research Fellow
School of Biology
Scottish Oceans Institute
University of St Andrews
http://biology.st-andrews.ac.uk/contact/staffProfile.aspx?sunid=njq