Stable oxygen and hydrogen isotope analyses of bowhead whale baleen as biochemical recorders of migration and arctic environmental change

An analysis of the stable isotopes of oxygen (delta O-18) and hydrogen (delta D) was used to examine the linkage between sea ice concentration and the migration of western arctic bowhead whales (Balaena mysticetus; WABW). We compared delta O-18 and delta D variability along the length of WABW baleen with isotopic values of zooplankton prey from different WABW habitat, with published delta C-13 and delta N-15 data, and with historical sea ice records. Zooplankton signatures varied widely (delta O-18 = -13 parts per thousand-56 parts per thousand; delta D = -220 parts per thousand to -75 parts per thousand), with regional separation between winter (Bering Sea) and summer (eastern Beaufort Sea) habitats of WABWobservable in delta D. The delta O-18 and delta D of WABW varied significantly along the length of baleen (delta O-18 = 8-18 parts per thousand; delta D = -180 to -80 parts per thousand), confirming seasonal migration and reflecting distinct regional dietary variation in isotopes. WABW migration appears to have varied concomitant with temporal sea ice concentration (SIC) changes; in years with high SIC, the difference in delta D of WABW baleen between seasonal habitats was significantly greater than low SIC periods. This work shows that SIC is not only a determinant of habitat accessibility for WABW, but baleen may also be a record of historical SIC and Arctic climate. (C) 2015 Elsevier B.V. and NIPR. All rights reserved.