Cook Inlet Beluga Whale Diet Using Stable Isotope Analysis

Determining whether changes have occurred in the diet of endangered Cook Inlet beluga whales (Delphinapterus leucas) is important for understanding whether diet was a factor in the population decline or is currently a factor in its recovery. Using bone from the skulls of Cook Inlet beluga whales, we determined isotope signatures for 23 belugas collected between 1965 and 2007. We also determined the isotope signatures of prey species found in stranded beluga stomachs, sport-caught salmon from Cook Inlet, and from recent literature to determine possible important prey items.