![]() Element:Ca ratios displayed ontogenetic trends, with Li:Ca, Zn:Ca, and Ba:Ca significantly higher before the birth mark in sharks captured in the GC. Most neonate and juvenile sharks caught in the Pacific had SIA that did not overlap with those of the GC, but a single subadult likely migrated to the GC. A subadult from the GC likely resided within the system throughout its life, and two subadults migrated into the GC. Mean δ 15N values from vertebral edges of GC sharks, representing the most recent feeding, was +5‰ higher than in the Pacific, reflecting the intense denitrification that permeates the regional food web and supporting SIA as tracers of migration between regions. ![]() Vertebrae from coastal Mexican artisanal fisheries off central Baja California in the Pacific (12 neonates and juveniles 139-280 cm total length) and the GC (3 subadults 289-355 cm TL) were analyzed to characterize (1) trophic histories from collagen δ 13C and δ 15N values, and (2) in utero patterns and post-birth environmental histories from element:Ca time-series. Two nursery areas in the northeastern Pacific are known, but migration patterns of immature White Sharks within the Gulf of California (GC) and natal philopatry are poorly understood. We reconstructed the habitat use and migratory history of young White Sharks ( Carcharodon carcharias), a highly protected species, by utilizing natural chemical tracers (element:Ca ratios and stable isotope analysis, SIA) in vertebral cartilage growth bands. The conservation and management of highly migratory sharks relies on understanding age-related movements and nursery habitat utilization.
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