The Paleoecology and Evolution of White Sharks: An Isotopic Study

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

Paul Koch The University of California-Santa Cruz The Paleoecology and Evolution of White Sharks: An Isotopic Study This is a study of modern and ancient shark ecology using stable isotope analysis, which permits the quantification of patterns and processes in ecological systems. While isotope systematics have not been studied extensively in sharks, based on the wide utility of isotopic methods in studies of the ecology and paleoecology of other vertebrates, we hope that our approach will broaden our understanding of shark ecology. To lay the foundation for both modern and paleontological research, we will analyze samples from a recently concluded controlled feeding study, which also included calcified structures. The interpretative framework set by our feeding study will allow us to assess the dietary and habitat preferences of modern white sharks off the California coast. We will sub-sample annual growth bands in the vertebrae of white sharks collected from the mid-to-late 20th century. Our study should reveal growth and seasonal shifts within an individual?s lifetime, as well as possible ecological changes associated with the increase in the marine mammal populations since the 1970s. Our project featuring modern and ancient white sharks will contribute to critical ecological questions, which are difficult to answer with other tools. Our past work have had practical impacts for our understanding of the ecology and conservation biology of modern species. This work has brought a new set of tools to modern ecology and it can offer an essential historical context for the study of modern ecosystems. This project will contribute to the education of UCSC graduate and undergraduate students. It will support the mentoring of a post-doctoral researcher. It will train a Ph.D. student. We expect undergraduate students to develop senior thesis projects around this study. We will explore developing a new course on historical marine ecology, using information from this proposal and prior studies of seals, condors, and other taxa. Our results will also contribute to a new fossil shark website associated with the Florida Natural History Museums Ichthyology Department. These outreach venues will allow educators, youth, and the general public to explore ancient and modern shark ecology.