Growth during the first summer at sea modulates sex-specific maturation schedule in Atlantic salmon

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Tréhin, Cécile, Rivot, Etienne, Lamireau, Ludivine, Meslier, Lisa, Besnard, Anne-Laure, Gregory, Stephen, Nevoux, Marie
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Unité Expérimentale d'Ecologie et d'Ecotoxicologie Aquatique - U3E (Rennes, France) (U3E ), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Salmon and Trout Research Centre, Game and Wildlife Conservation Trust, The Game and Wildlife Conservation Trust
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDE.MCG]Environmental Sciences/Global Changes; Atlantic salmon; Salmo salar
• Online Access: https://hal.inrae.fr/hal-03223271; https://doi.org/10.1139/cjfas-2020-0236

International audience Recent decline in abundance of Atlantic salmon (Salmo salar) and concomitant changes in life history may result from a decline in the growth conditions during marine migration. Available literature suggests the existence of a sex-specific reaction norm linking maturation with environmental growth conditions at sea. However, the extent to which this mechanism explains variations in age at maturity remains unclear. Using a historical collection of scales (1987–2017) from the Sélune River, France, we showed that marine growth declined over the first summer and remained stable during the subsequent periods at sea among returning salmon. Results support the hypothesis of a sex-specific probabilistic reaction norm, with individual probability to return after 1 year at sea increasing when growth increases. Females may require higher growth than males to attain their maturation threshold. This mechanism is a good candidate to explain temporal variability in sea-age at return at both the individual and population level in the Sélune population and in many other southern European populations.