Intraskeletal variability in stable isotope ratios of C and N among pinnipeds and cetaceans

Abstract

Stable isotope analysis of C and N has become a popular method for addressing questions on the trophic ecology andhabitat use of marine mammals (Newsome, Clementz, & Koch, 2010; Rubenstein & Hobson, 2004). The method isparticularly useful for studying: rare species that can be accessed by researchers only after stranding (e.g., Riccialdelli,Newsome, Fogel, & Goodall, 2010); the cryptic stages of more abundant species (e.g., Kernaléguen et al., 2012; Vales,Cardona, García, Zenteno, & Crespo, 2015); niche partitioning between sympatric species (e.g., Pinela, Borrell,Cardona, & Aguilar, 2010; Riccialdelli et al., 2010); and historical changes in marine mammal ecology by means either ofspecimens stored in scientific collections (e.g., Drago et al., 2009; Zenteno et al., 2015) or of those recovered fromarchaeological sites (e.g., Bas et al., 2019; Szpak, Buckley, Darwent, & Richards, 2018; Vales et al., 2017).