Validation of otolith δ18O values as effective natural tags for shelf-scale geolocation of migrating fish

Marine ecology progress series

Audrey M. Darnaude^1,2¹  Ewan Hunter^2,3² 

[1] CNRS, UMR 9190 MARBEC, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France^1;Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Lowestoft, Suffolk NR33 0HT, UK^2;School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK^3

关键词: Fish migration;    Oxygen;    Stable isotopes;    Natural tag;    Site fidelity;    Plaice;    Pleuronectes platessa;   

DOI  :  10.3354/meps12302

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

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 δ18O 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 δ18O-based geolocation of fish during their annual migrations. Detailed intra-annual otolith δ18O measurements for 1997-1999 from individuals of 3 distinct sub-stocks with different spawning locations were compared with δ18O 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 δ18O values (-0.23 to 2.94‰) mainly reflected variation in temperature, and among-zone discrimination potential using otolith δ18O varied greatly by temporal scale and by time of year. Measured otolith δ18O values (-0.71 to 3.09‰) largely mirrored seasonally predicted values, but occasionally fell outside expected δ18O 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 δ18O. Comparing intra-annual δ18O 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 δ18O values can therefore provide relatively detailed fisheries-relevant data not readily obtained by conventional means.

【 授权许可】

Unknown