Approaches to understanding the cumulative effects of stressors on marine mammals.

Abstract

In 2017, The National Academy of Sciences reported on the approaches to understanding the cumulative effects of stressors on marine mammals and suggested the use of baleen whale earplugs to evaluate both stress and stressors. The objective of this dissertation is to investigate historic and current organic and inorganic contaminants within the marine ecosystem to better understand the cumulative effects of stressors on marine mammals. Simultaneously, this dissertation also demonstrate links between. The long-term health impact of organic contaminants was assessed in harbor porpoises off the coast of Washington State. This study focused on the POP burden within the blubber of three females (two adults and one juvenile), one of which had a Bcell lymphoma. POP blubber concentrations from different life stages were used to assess the lifetime POPs burden. The juvenile porpoise had the highest contaminant burden followed by the adult female with lymphoma and the nonlymphoma adult. POP life history exposure profiles were reconstructed using baleen whale earplugs. This earplug study expands upon previous earplug studies of both spatial and temporal trends. POPs analysis using earplugs provided contaminant data 30 years prior to the first reports in marine species. Chemical exposure profiles and bioaccumulation rates were reconstructed for a total of six earplugs from the North Pacific and Atlantic Ocean basins. Bioaccumulation rates were found to be 56 times higher in the North Pacific compared to the North Atlantic, suggesting a higher risk of exposure in the North Pacific. Lastly, a single earplug was used to investigate temporal profiles of inorganic elements. The final study used a single fin whale earplug to produce more than 1,600 data points, which were used to reconstruct 48 distinct profiles of toxic, essential, nonessential, rare earth, and other non-biologically relevant elements. This research, in conjunction with concurrent studies, aimed to examine stress profiles and other stressors (e.g., reproduction and whaling; see appendix). Earplug data from this study provides insight into biological and biogeochemical processes as well as preliminary data for further elemental analysis of more earplugs.