Widespread high prevalence of vaterite in pink salmon (Oncorhynchus gorbuscha) otoliths

Pacific salmonids rely on precise sensory mechanisms, including the sagittal otolith, to support long-distance migrations. Vaterite replacement of otolith aragonite can impair sensory function, and compromise otolith-based reconstructions of environmental history. Otoliths from 1,116 native and invasive pink salmon across the Pacific and Atlantic Oceans were examined for vaterite prevalence, extent, and timing of formation. Visual assessment proved to be a reliable and efficient method for identifying otolith mineralogy, based on validation using X-ray diffraction. We document exceptionally high vaterite prevalence in pink salmon from both Atlantic (97%) and Pacific (94-96%) populations, with minimal geographic variation and no differences among native and invasive or wild and hatchery populations. Vaterite levels far exceeded those reported for other salmonids, including hatchery-reared populations. Our results indicate that vaterite formation can occur at any life stage, beginning as early as the juvenile freshwater stage and peaking early in the marine phase. Overall, our findings support an association between the unusually high prevalence of vaterite in pink salmon and a life-history strategy characterized by rapid growth.