Physiological traits of the Greenland shark Somniosus microcephalus obtained during the TUNU-Expeditions to Northeast Greenland

Arctic regions are inhabited by cold-adapted stenothermal or eurythermal species. Unlike in the Antarctic, eurythermal species predominate, because of opportunities for migrations to temperate latitudes. In the Antarctic sea, the modern chondrichthyan genera are scarcely represented. In contrast, in the Arctic, sharks and skates are present with about 8% of the species (Mecklenburg et al., 2011; Lynghammar et al., 2013). The distribution of the Greenland shark Somniosus microcephalus is quite wide; in fact, this species typically thrives in deep and extremely cold waters, seasonally covered by sea ice (MacNeil et al., 2012), but is also known to enter more temperate waters in the North Atlantic (Bigelow & Schroeder, 1948; Skomal & Benz, 2004). Widespread climate changes in the arctic ecosystem have led to increased attention on trophic dynamics and on the role of this apex predator in the structure of arctic marine food webs (MacNeil et al., 2012).