Ontogenetic Patterns of Elemental Tracers in the Vertebrae Cartilage of Coastal and Oceanic Sharks

As predators, coastal and oceanic sharks play critical roles in shaping ecosystem structure function, but most shark species are highly susceptible to population declines. Effective management of vulnerable populations requires knowledge species-specific movement habitat use patterns. Since often mobile long-lived, tracking their patterns over large spatiotemporal scales is challenging. However, the analysis elemental tracers vertebral cartilage can describe a continuous record life history an individual from birth death. This study examined trace elements (Li, Mg, Mn, Zn, Sr, Ba) along transects five with unique histories. From freshwater-associated oceanic, these include Bull Sharks ( Carcharhinus leucas ), Bonnethead Sphyrna tiburo Blacktip limbatus Spinner brevipinna Shortfin Mako Isurus oxyrinchus ). Element concentrations were compared across stages (young-of-the-year, early juvenile, late adult) infer ontogenetic movement. Many observed could be explained by known traits: C. exhibited clear changes composition matching expected freshwater habitats time. S. did not differ ontogeny, suggesting residence estuarine/coastal regions. The strikingly similar between , they co-occur ontogeny. I. was stable time, some shifts occurred that may due migration maturation. results presented this enhance our understanding sharks, highlights applicability chemistry as tool for characterizing traits.