[MARMAM] New publication - Identification of seal foraging areas (horizontal vs. vertical approaches)

yann.planque at univ-lr.fr yann.planque at univ-lr.fr
Thu Jan 30 00:51:13 PST 2020

Dear colleagues,

We are pleased to share you our new publication on *'Comparing the 
horizontal and vertical approaches used to identify foraging areas of 
two diving marine predators'* by Yann Planque, Mathilde Huon, Florence 
Caurant, David Pinaud and Cécile Vincent, in Marine Biology.


Accurately locating the foraging areas of diving marine predators is 
central to understanding their ecology and implementing conservation and 
management regulations. This study compares horizontal and vertical 
approaches of identifying seal foraging areas. We analysed GPS locations 
and dive data obtained from GPS/GSM tags fitted on eight grey seals 
(/Halichoerus grypus/) and nine harbour seals (/Phoca vitulina/). In the 
horizontal dimension, we used the First Passage Time to identify 
Area-Restricted Search (ARS) behaviour. In the vertical dimension, we 
used two dive criteria indicating benthic foraging behaviour: dive shape 
and vertical descent speed. The two approaches were spatially compared 
using the Index of Differences in Spatial Pattern. We found that the two 
approaches highlight similar hotspots when pooling all individuals of 
the same species. However, the degree of overlap varied considerably at 
the individual level. Some individuals performed most of their likely 
foraging dives (vertical dimension) in areas where they also displayed 
ARS behaviour (horizontal dimension), while others performed these dives 
both in and outside ARS zones. We suggest that comparing foraging areas 
detected from horizontal and vertical approaches (1) can strengthen the 
confidence in the efficiency of approaches to accurately spatialize the 
actual foraging effort of a diving predator at the scale of a colony 
(sampled with several individuals); and (2) provides more comprehensive 
insights into potential interindividual differences in foraging 
strategies as some divergent individual strategies may not be detected 
using only horizontal movements.

Planque, Y., Huon, M., Caurant, F., Pinaud, D., Vincent, C. Comparing 
the horizontal and vertical approaches used to identify foraging areas 
of two diving marine predators. /Mar Biol/ 167, 25 (2020). 

If you do not have access to Marine Biology, do not hesitate to contact 
me at yann.planque at univ-lr.fr.

Best regards,

Yann Planque

Yann Planque
Doctorant / PhD student
*La Rochelle Université*
Centre d'Etudes Biologiques de Chizé (CEBC, UMR 7372 CNRS/ULR)

Centre Commun d'Analyses
5 allée de l'Océan, 17 000 La Rochelle, France
Tel: +33 (0)5 46 50 76 42
www.cebc.cnrs.fr <http://www.cebc.cnrs.fr>
www.univ-larochelle.fr <http://www.univ-larochelle.fr>

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