Using isotopic fingerprints in gastropod shells to validate commercial production pathway and geographic provenance.

Growing demand for high-value seafood is fuelling provenance fraud, which threatens the sustainability of wild fisheries while posing biosecurity and human health risks. Here, we investigated carbon ( δ 13 C) and oxygen ( δ 18 O) isotopes in abalone shells ( Haliotis sp.) to determine the production method and geographical provenance. Using X-ray diffraction and isotope ratio mass spectrometry, we found that shell mineralogy did not influence isotope values. Isotope values between wild and farmed sectors were statistically different, with 64% of individuals correctly classified as farmed or wild. Subsequently, we successfully distinguished the provenance of abalone collected from farms (with 83% of individuals correctly classified), as well as wild-caught abalone collected from four state jurisdictions (with 88% correctly classified). Carbon isotopes were strongly correlated to longitude, with both isotopes correlated to latitude. Overall, this study demonstrates the potential of isotopic fingerprints in gastropod shells to track the provenance of commercially valuable species.