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Isotopic, tagging and diet studies of modern-day teleosts lacked the ability to contextualise life-history and trophic dynamics with a historical perspective, when exploitation rates were lower and climatic conditions differed. Isotopic analysis of vertebrae, the most plentiful hard-part in archaeological and museum collections, can potentially fill this data-gap. Chemical signatures of habitat and diet use during growth are retained by vertebrae during bone formation. Nonetheless, to fulfil their potential to reveal life-history and trophic dynamics, we need a better understanding of the time frame recorded by vertebrae, currently lacking due to a poor understanding of fish bone remodelling. To address this issue, the authors serially-sectioned four vertebral centra of the highly migratory Atlantic bluefin tuna (Thunnus thynnus; BFT) captured off Sardinia (Italy) and analysed their isotopic composition. They show how carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) isotope values can vary significantly across BFT vertebrae growth-axes, revealing patterning in dietary life histories. Further, they find that similar patterns are revealed through incremental isotopic analysis of inner and outer vertebrae centra samples from 13 archaeological BFT vertebrae dating between the 9th and13th centuries CE. The results indicate that multi-year foraging signatures are retained in vertebrae and allow for the study of life histories in both modern and paleo-environments. These novel methods can be extended across teleost taxa owing to their potential to inform management and conservation on how teleost trophic dynamics change over time and what their long-term environmental, ecological and anthropological drivers are.
Bibliographical noteFunding Information:
We thank Matt Von Tersch and Maria Fontanals‐Coll for laboratory assistance. We are grateful to the Istanbul Archaeological Museum, and the General Directorate of Cultural Heritage and Museums of the Ministry of Culture in Turkey for permission and support given to Prof. Vedat Onar – 143362/01.09.2006 related to the analyses of remains from the archaeological site of Yenikapi. This work is a contribution to the https://tunaarchaeology.org project within the framework of the MSCA SeaChanges ITN, which was funded by EU Horizon 2020 (grant number: 813383).
© 2023 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.
- fish bone turnover
- historical ecology
- life histories of fishes
- serial sectioning
- stable isotope analysis