[MARMAM] New publication: A new method to study inshore whale cue distribution from land-based observations (Patricia Arranz)

[Patricia Arranz]

Dear all,


We are pleased to announce our recent publication:

"A new method to study inshore whale cue distribution from land-based 
observations"

 1.

    Patricia Arranz, Sea Mammal Research Unit, University of St Andrews,
    Scotland and Department of Animal Biology, La Laguna University, Spain.

 2.

    David Borchers, Centre for Research into Environmental and
    Ecological Modeling, University of St Andrews, Scotland.

 3.

    Natacha Aguilar de Soto, Sea Mammal Research Unit, University of St
    Andrews, Scotland and Department of Animal Biology, La Laguna
    University, Spain.

 4.

    Mark P. Johnson, Sea Mammal Research Unit, University of St Andrews,
    Scotland.

 5.

    Martin J. Cox, Pelagic Ecology Research Group, Scottish Oceans
    Institute, University of St Andrews, Scotland.

Author for correspondence: parranz at st-andrews.ac.uk


SUMMARY

The challenges involved in the visual detection of some cetacean species 
make it difficult to obtain information about their distribution and 
habitat preferences using traditional sampling methods. This is 
particularly the case for species such as beaked whales that spend a 
small amount of time at the surface and have inconspicuous surface 
behavior. The coastal waters around El Hierro (Canary Islands) hold 
year-round populations of two beaked whale species, Cuvier's (/Ziphius 
cavirostris/) and Blainville's (/Mesoplodon densirostris/), providing an 
ideal scenario to set up land-based point transect surveys to study the 
inshore behavior of these deep-diving species. This work extends 
traditional distance sampling methods to allow the distribution of 
animals seen from an observation point on the coast to be modeled with 
respect to a nonlinear environmental feature (water depth). Depth is a 
key factor delimiting marine habitats and is especially relevant for 
understanding the distribution of deep-diving species such as beaked 
whales, which approach the seafloor to feed. Our model predicts the 
highest density of beaked whale cues around the 1,000 m isobath and most 
(90%) of beaked whale groups surfacing in waters with seabed depths 
between 325 and 1,660 m depth. The distribution of the sightings suggest 
that the habitat selection of both species is probably driven by an 
increased prey availability on the slope of the island. Because the 
number of sightings at a given depth is not necessarily proportional to 
the number of groups present, in this particular case additional 
information on surfacing rates, and how they vary with depth, will be 
required to draw inferences about animal distribution. We conclude that 
this method is useful to investigate the distribution and habitat 
selection of animals in relation to environmental variables using 
observations from land and that future development work will allow 
covariates in the detection function or multiple environmental features 
to be considered when implementing density estimates.


The pdf can be downloaded from here: 
_http://onlinelibrary.wiley.com/doi/10.1111/mms.12077/abstract_

Or a pdf copy can be obtained upon request to: _parranz at st-andrews.ac.uk 
<mailto:parranz at st-andrews.ac.uk>_


Patricia Arranz, Ph. D.
Sea Mammal Research Unit
Scottish Oceans Institute
School of Biology
University of St Andrews
St Andrews
KY16 8LB
Scotland



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