Doctoral Dissertation Research: Isotopic Analysis of Icelandic Cod Atlases: Tracing Trophic Changes Over a Millennium

This research investigates how shifts in Arctic environments and human activities have affected the feeding behaviors and food chain positions of Atlantic cod over the past thousand years. Understanding these changes is important because Atlantic cod play a crucial role in the Arctic marine ecosystem. Atlantic cod are an essential food source for both marine animals and people. Cod also contribute significantly to the regional economy and cultural identity of Arctic communities. Recent environmental shifts have intensified habitat changes and increased fishing pressures in Arctic regions, impacting species like Atlantic cod and the ecological and economic systems they support. This study uses an innovative technique to track dietary shifts in cod by analyzing chemical signatures in ancient cod bones from archaeological sites. The results will help determine whether the changes in cod’s feeding patterns align with historical increases in fishing, changes in fishing methods, or other natural fluctuations. The outcomes can provide valuable data for fisheries science and policy, supporting efforts to build sustainable fishing practices in response to long-term environmental variability. This project will use segmental isotope analysis of fish vertebrae (SIAV) to reconstruct high-resolution dietary life histories for Atlantic cod (Gadus morhua) from archaeological sites spanning the last millennium. By analyzing sequential stable isotope values of nitrogen (δ15N) and carbon (δ13C) in individual vertebrae, this project will trace the trophic positions of individual fish throughout their lives. This approach offers greater detail than bulk stable isotope analysis, which typically provides an average dietary signature that may mask specific ecological events. This research will address two primary questions: 1) Have trophic positions of Atlantic cod populations changed over the last millennium? and 2) Are these changes associated with increased fishing pressure, shifts in fishing practices, or natural environmental variability? Additionally, this project highlights the potential of fish vertebrae as a data source in archaeological studies, providing a new model for analyzing historical and ecological changes across Arctic marine systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.