Insight into niche separation of Risso's dolphin (Grampus griseus) in the southwestern South Atlantic via d13C and d15N values

摘要

Risso’s dolphin, Grampus griseus, is a small cetacean distributed worldwide in temperate and tropical oceans (Baird 2009). The distribution of this species in Argentine waters is not clear but appears to be continuous (Bastida et al. 2007), and includes the northern coast of Tierra del Fuego. Twelve mass strandings and 13 single strandings have been reported for Tierra del Fuego (Goodall et al. 2008), however, mass strandings are generally considered uncommon for this species (Baird 2009).