Longitudinal biomarker and chemical analyses in marine vertebrates.


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Oceans covers over 70% of the Earth’s surface and regulates climate, provides food, energy, and transportation, as well as being important for religious or cultural traditions. Currently, approximately 40% of the global population lives within 200 km of the ocean. Over the past century, the oceans and their inhabitants have been subjected to an increase in the scope, magnitude, and footprint of anthropogenic activities (shipping, noise, toxins, temperature, over-fishing), which threaten the productivity and health of the oceans. Researchers have employed periodic sampling (blubber, skin, blood, muscle) to address issues regarding the impacts of anthropogenic or environmental perturbations on animals and ecosystems. However, these sampling methods provide a “snapshot” of the health of an individual or the targeted ecosystem and cannot consider baseline differences in targeted analytes among individuals. Obtaining longitudinal analyte data from an individual animal provides a time-series of data to assess change over time and/or can baseline correct differences among individuals. The fundamental questions to be addressed in this dissertation include examining time-specific longitudinal data obtained from incrementally grown tissues in long-lived fish (rockfish; ~100 years) and pinniped (leopard seal) species to 1A) determine/validate steroid hormone concentrations (progesterone, estradiol, and cortisol) in annual growth increments obtained from a teleost operculum 1B) estimate reproductive parameters implemented in fish population models (e.g., age of sexual maturity and spawning frequency) and quantify stress events; 2) correlate lifetime reproductive and stress data with environmental variables; 3A) develop temporal records of trace elements with paired stable isotope analysis for information on diet from whiskers; and 3B) determine trace element changes in whiskers over time with diet. Key findings include validating novel methods to obtain lifetime longitudinal reproductive and stress data in a long-lived teleost that may help improve fish population models and assess physiological resiliency to environmental change. Additionally, contaminant with paired diet time-series data were reconstructed in the leopard seal, which provides critical physiological and ecological data for a remote and elusive apex Antarctic predator. This dissertation provides a suite of methods for obtaining longitudinal records of biological data to examine the resilience of elusive marine vertebrates to climate change.