| Summary: | Submarine canyons have long been considered important areas for marine life supporting abundant and unique communities of megafauna, including sometimes species not observed in other environments. These emerged valleys are becoming increasingly recognised as recurrent sources of enhanced productivity (Allen et al., 2001; Genin, 2004) and habitat heterogeneity. Indeed, they provide important habitat for various life stages of benthic and demersal fishes and invertebrates along continental margins (Demestre & Martìn, 1993; Stefanescu et al., 1994). These physiographic features may also serve as ‘keystone structures’ and aggregation area of top predators like tuna, sharks and marine mammals. The bottom topography of the north-western Mediterranean Sea is not a uniform flat environment. It’s characterized by the presence of some geomorphologic features as seamounts, and is incised for the most part by several submarine canyons. These deep incised valleys occupy nearly 50% of the continental slope (Gili et al., 2000). This area constitutes one of the pools of greatest diversity and highest production (Franqueville, 1971; Andersen et al., 2001), stimulating the regular presence of eight cetacean species (Notabartolo di Sciara, 2002). The aggregation of various teutophageous, planktophageous and ichtyophageous cetaceans may reveal the high productivity of this area. Several studies attempted to correlate cetacean distribution to geomorphologic features inside the Mediterranean Sea (Gannier, 1998; Cañadas et al., 2002; Azzellino et al., 2008; Aïssi et al., 2008; Moulins et al., 2008). It seems that as well as depth and slope, submarine canyons play an important influence on cetacean distribution, even if modalities and intensities depend on hydrological, topographical, and biological contexts. It was confirmed that habitat selection for Cuvier’s beaked whale is associated particularly to steep slopes and submarine canyons (Moulins et al., 2007). For example, the Genoa canyon was described as specific attractive area ...
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