NSF Postdoctoral Fellowship in Biology FY 2013

Madigan Daniel J, Oakland CA

Investigators

Abstract

Using complementary chemical tracer techniques to elucidate past migration patterns of Pacific open ocean predators Highly migratory marine predators provide top-down ecological controls and maintain pelagic ecosystem biodiversity. These predators face uncertain futures due to changing ocean conditions, exploitation of prey resources, and fishing pressure. Understanding movement patterns is crucial to understanding predator biology and working towards ecosystem management. This project will combine Fukushima-derived radiocesium, bulk stable isotope analysis, and amino acid-specific stable isotope analysis to generate novel insights into the movements of Pacific bluefin tuna, albacore tuna, sharks, sea turtles, and marine mammals. The use of these approaches in concert will ground-truth the use of bulk stable isotope analysis for use ad infinitum in ocean systems, allowing for the analysis of changing migration patterns in response to changing ocean conditions in the future. This study is an intersection of ecology, organismal biology, radiochemistry, and physiology. Training objectives include sampling of pelagic animals in the Pacific, bulk and amino acid-specific stable isotope analysis, gamma spectrometry, and mathematical modeling of Cs cycling in tunas and other large organisms. Mentors and collaborators include experts in pelagic ecology, metal biogeochemistry and radioanalysis, stable isotope analysis, and mathematical modeling. Broader impacts include direct use of migration data in fisheries management models that necessitate international cooperation. This multi-species approach will demonstrate the assimilation and consequent transport of radioactive material. Public outreach upon data publication will put radiocesium levels in food fish in the context of safety limits. As such, the impacts of this study are broad and have implications in social, health, economic, environmental, and fisheries policy realms.