| The foraging grounds of the endangered North Atlantic right whale ( Eubalaena glacialis) are protected under management rulings, but several datasets suggest that right whales use habitats far beyond these areas. In 2005, the National Marine Fisheries Service published a Right Whale Recovery Plan citing the "characterization and monitoring of important habitats" as high research priorities.;Stable isotopes ratios in animal tissue are intrinsic tags of migration, as they vary regionally in the environment, and are assimilated via trophic transfer. This dissertation describes carbon, nitrogen, oxygen, and hydrogen stable isotope ratios in baleen and zooplankton collected in the Gulf of Maine, and their application in determining the migration patterns and foraging ecology of E. glacialis.;The Gulf of Maine stable isotope landscape was examined through analysis of zooplankton samples from seven E. glacialis habitats. Cape Cod Bay, Great South Channel, and the Bay of Fundy represent distinct isotope sources to right whales. All other habitat areas were statistically indistinguishable, and seasonal right whale movements between these areas cannot be resolved with stable isotope geochemistry.;Isotope records in E. glacialis baleen, like those of other large whale species, contain annual oscillations that correspond to broad-scale north/south migrations. To examine right whale movement patterns at seasonal time scales, baleen isotope records, the North Atlantic Right Whale Catalog sighting records, and habitat-specific zooplankton stable isotope values were compared. Poor correlations were found between observed and expected baleen isotope values, likely because of the confounding contribution of body nutrient pools that were de-coupled from diet (i.e. non-essential amino acids).;Comparisons of recently collected E. glacialis baleen data with isotope records from late 19th--early 20 th century baleen revealed a long-term decrease in carbon and increase in nitrogen isotopes. The observed trends are attributed to increasing anthropogenic inputs of carbon dioxide and nitrogen species, climatic forcing from the North Atlantic and Pacific Decadal Oscillations, and poor overall health in the present-day right whale population.;The results of this study revealed that right whales use "historic habitat" areas more frequently than currently assumed, and demonstrates both the spatial/temporal limitations of the stable isotope method and the confounding effect of fluctuating biogeochemical signals in the environment. |
