Age, movements, and feeding ecology of northwest Atlantic white sharks estimated from ecogeochemical profiles in vertebrae
Hamady, Li Ling
MetadataShow full item record
White sharks (Carcharodon carcharias) are highly migratory, ecologically important, vulnerable, and understudied marine predators. Ecogeochemistry, which takes advantage of natural variations in chemical signatures recorded in body tissues, can help determine lifetime movement, age, and ontogenetic diet history in difficult to study species. Shark vertebrae are constructed of distinct layers of tissue laid down sequentially over an individual’s lifetime and may preserve a chemical record of environmental exposure. In this thesis, I investigate the ecology of the understudied northwest Atlantic (NWA) white shark population by applying several ecogeochemistry techniques to their vertebrae. I generate the first radiocarbon (Δ14C) age estimates for adult white sharks, dramatically extending the maximum age and longevity compared to earlier age studies. Δ14C results also verify a lack of reworking of vertebral material and hint at possible sexual dimorphism in growth rates. Using amino acid and bulk stable isotope analyses, I show that individual sharks have marked variation in feeding and movement, and that pinnipeds do not constitute a large portion of their diet. Finally, I explore the utility of elemental chemistry to retrospectively infer movement. This work provides an important informational baseline for future NWA white shark ecological studies and conservation and management efforts.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2014
Suggested CitationThesis: Hamady, Li Ling, "Age, movements, and feeding ecology of northwest Atlantic white sharks estimated from ecogeochemical profiles in vertebrae", 2014-02, DOI:10.1575/1912/6505, https://hdl.handle.net/1912/6505
Showing items related by title, author, creator and subject.
Silverthorne, Katherine E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2010-06)Observational and modeling techniques are employed to investigate the thermal and inertial upper ocean response to wind and buoyancy forcing in the North Atlantic Ocean. First, the seasonal kinetic energy variability of ...
Eggen, Trym H. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-06)This work is concerned with coherent communication by means of acoustic signals over underwater communication channels. The estimated scattering functions of real data ranging from the Arctic environment to tropical ...
Coral reefs in the Anthropocene Ocean: novel insights from skeletal proxies of climate change, impacts, and resilience Mollica, Nathaniel R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2021-02)Anthropogenic emissions of greenhouse gases are driving rapid changes in ocean conditions. Shallow-water coral reefs are experiencing the brunt of these changes, including intensifying marine heatwaves (MHWs) and rapid ...