Isotopic composition of the eastern gray whale epidermis indicates contribution of prey outside Arctic feeding grounds.

Eastern gray whales' distribution range and plasticity in feeding behavior complicates the understanding of critical life-history such as pregnancy and lactation. Our goal was to determine if females who experienced gestation, gave birth, and lactated their calves, assimilated a high proportion of benthic amphipods from the Bering Sea, which are considered the species' main prey. We used Bayesian stable isotope mixing models to estimate the probability of contribution of food items sampled along the species' distributional range, using isotopic data on amphipods from the Bering Sea, mysids from Vancouver Island, and amphipods and polychaetes from Ojo de Liebre Lagoon.