Spatial and temporal variations in otolith chemistry and relationships with water chemistry: a useful tool to distinguish Atlantic salmon Salmo salar parr from different natal streams

• Main Authors: Martin, J., Bareille, G., Berail, S., Pecheyran, C., Daverat, Françoise, Bru, N., Tabouret, H., Donard, O.
• Other Authors: Centre National de la Recherche Scientifique (CNRS), Ecosystèmes estuariens et poissons migrateurs amphihalins (UR EPBX), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDE]Environmental Sciences; Atlantic salmon; Salmo salar
• Online Access: https://hal.inrae.fr/hal-02598682

International audience Otolith elemental (Sr:Ca, Ba:Ca, Mn:Ca, Mg:Ca and Rb:Ca) and isotopic (87Sr:86Sr) profiles from several annual cohorts of juvenile Atlantic salmon Salmo salar were related to the physico-chemical characteristics (chemical signatures, flow rate, temperature and conductivity) of their natal rivers over an annual hydrological cycle. Only Sr:Ca, Ba:Ca and 7Sr:86Sr in otoliths were determined by their respective ratios in the ambient water. Sr:Ca ratios in stream waters fluctuated strongly on a seasonal basis, but these fluctuations, mainly driven by water flow regimes, were not recorded in the otoliths. Otolith Sr:Ca ratios remained constant during freshwater residency at a given site and were exclusively related to water Sr:Ca ratios during low flow periods. While interannual differences in otolith elemental composition among rivers were observed, this variability was minor compared to geographic variability and did not limit classification of juveniles to their natal stream. Success in discriminating fish from different sites was greatest using Sr isotopes as it remained relatively constant across years at a given location.