Figure 2

Biplot of dentine δ¹⁸O_P versus Suess-adjusted δ¹³C_SC values of teeth from eastern Canadian Arctic (ECA; turquoise circles) and Northwest Atlantic (NWA; purple squares) killer whales relative to bone values of killer whales from Greenland (light purple diamonds) and Denmark (green triangles). The range of δ¹⁸O_P indicates considerable spatial separation. This result reflects latitudinal gradients in the North Atlantic, suggesting considerable spatial structuring among killer whales in both the ECA and NWA. Although dietary influences on δ¹³C confound direct interpretations within a spatial context, the range in δ¹³C_SC values exceeds that expected due to dietary differences alone. The δ¹³C_SC were adjusted by − 0.023‰ year⁻¹ up to the year 2013 (the most recent sample) to account for temporal bias due to baseline shifts (Suess effect^42,43) in North Atlantic δ¹³C over the timespan of collected specimens (see Figure S2).