TY - JOUR T1 - Validation of otolith δ18O values as effective natural tags for shelf-scale geolocation of migrating fish A1 - Darnaude,Audrey M. A1 - Hunter,Ewan AD - Univ Montpellier, UMR MARBEC 9190, CNRS, Pl Eugene Bataillon, F-34095 Montpellier, France. AD - Lowestoft Lab, Ctr Environm Fisheries & Aquaculture Sci, Lowestoft NR33 0HT, Suffolk, England. AD - Univ East Anglia, Sch Environm Sci, Norwich Res Pk, Norwich NR4 7TJ, Norfolk, England. UR - https://doi.org/10.3354/meps12302 DO - 10.3354/meps12302 KW - Fish migration KW - Oxygen KW - Stable isotopes KW - Natural tag KW - Site fidelity KW - Plaice KW - Pleuronectes platessa N2 - The oxygen isotopic ratio of fish otoliths is increasingly used as a 'natural tag' to assess provenance in migratory species, with the assumption that variations in delta O-18 values closely reflect individual ambient experience of temperature and/or salinity. We employed archival tag data and otoliths collected from a shelf-scale study of the spatial dynamics of North Sea plaice Pleuronectes platessa L., to examine the limits of otolith delta O-18-based geolocation of fish during their annual migrations. Detailed intra-annual otolith delta O-18 measurements for 1997-1999 from individuals of 3 distinct sub-stocks with different spawning locations were compared with delta O-18 values predicted at the monthly, seasonal and annual scales, using predicted sub-stock specific temperatures and salinities over the same years. Spatio-temporal variation in expected delta O-18 values (-0.23 to 2.94%) mainly reflected variation in temperature, and among-zone discrimination potential using otolith delta O-18 varied greatly by temporal scale and by time of year. Measured otolith delta O-18 values (-0.71 to 3.09%) largely mirrored seasonally predicted values, but occasionally fell outside expected delta O-18 ranges. Where mismatches were observed, differences among sub-stocks were consistently greater than predicted, suggesting that in plaice, differential sub-stock growth rates and physiological effects during oxygen fractionation enhance geolocation potential using otolith delta O-18. Comparing intra-annual delta O-18 values over several consecutive years for individuals with contrasted migratory patterns corroborated a high degree of feeding and spawning site fidelity irrespective of the sub-stock. Informed interpretation of otolith delta O-18 values can therefore provide relatively detailed fisheries-relevant data not readily obtained by conventional means. Y1 - 2018/06 PB - Inter-research JF - Marine Ecology Progress Series SN - 0171-8630 VL - 598 SP - 167 EP - 185 ID - 73782 ER -