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Ecological niches of three teuthophageous odontocetes in the northwestern Mediterranean Sea
1Centre de Recherche sur les Cétacés – Marineland, Antibes, France
2MARE Center – Laboratory for Oceanology, University of Liège, Liège, Belgium
3Groupe de Recherche sur les Cétacés, Antibes, France
Abstract. In the northwestern Mediterranean Sea, sperm whales, pilot whales and Risso's dolphins prey exclusively or preferentially on cephalopods. In order to evaluate their competition, we modelled their habitat suitability with the Ecological Niche Factor Analysis (ENFA) and compared their ecological niches using a discriminant analysis. We used a long term (1995–2005) small boat data set, with visual and acoustic (sperm whale) detections. Risso's dolphin had the shallowest and the more spatially restricted principal habitat, mainly located on the upper part of the continental slope (640 m mean depth). With a wider principal habitat, at 1750 m depth in average, the sperm whale used a deeper part of the slope as well as the closest offshore waters. Finally, the pilot whale has the most oceanic habitat (2500 m mean depth) mainly located in the central Ligurian Sea and Provençal basin. Therefore, potential competition for food between these species may be reduced by the differentiation of their habitats.
Final Revised Paper (PDF, 1773 KB) Discussion Paper (OSD)
Citation: Praca, E. and Gannier, A.: Ecological niches of three teuthophageous odontocetes in the northwestern Mediterranean Sea, Ocean Sci., 4, 49-59, 2008. Bibtex EndNote Reference Manager
