MEPS 436:257-272 (2011)  -  DOI:

Modelling sperm whale habitat preference: a novel approach combining transect and follow data

Enrico Pirotta1,*, Jason Matthiopoulos1,2, Monique MacKenzie2, Lindesay Scott-Hayward2, Luke Rendell1

1Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St. Andrews, St. Andrews, Fife KY16 8LB, UK
2Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, St. Andrews, Fife KY16 9LZ, UK

ABSTRACT: Sperm whale Physeter macrocephalus habitat preferences are still poorly understood in the Mediterranean, despite the population being classified as ‘Endangered’ by the IUCN. Techniques to make the best use of multiple data sources are important in improving this situation. This work provides a detailed evaluation of sperm whale distribution and habitat use around the Balearic Islands using a novel analytical framework that combines transect and follow data while accounting for any autocorrelation present. During dedicated research cruises (2003 to 2008), sperm whales were located by listening at regular intervals along a search track and subsequently followed acoustically. Sperm whales were encountered 56 times and followed for periods ranging from a few hours to 3 d. Logistic Generalized Additive Models were used to model the probability of whale presence across the study area as a function of environmental variables, and Generalized Estimating Equations were used to account for autocorrelation. The results suggest that sperm whales do not use the region uniformly and that topography plays a key role in shaping their distribution. Moreover, solitary individuals were found to use the habitat differently from groups. This segregation appeared to be driven by water temperature and might reflect different needs or intraspecific competition. By shedding light on sperm whale habitat preference in such a critical area, this study represents an important step towards the implementation of conservation measures for this population.

KEY WORDS: Habitat modelling · Cetacean · Distribution · Balearic Islands · GAM · GEE · Multi-scale

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Cite this article as: Pirotta E, Matthiopoulos J, MacKenzie M, Scott-Hayward L, Rendell L (2011) Modelling sperm whale habitat preference: a novel approach combining transect and follow data. Mar Ecol Prog Ser 436:257-272.

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