Spatial synchrony in the response of a long range migratory species ( Salmo salar ) to climate change in the North Atlantic Ocean

• Published in: Global Change Biology
• Main Authors: Olmos, Maxime, Payne, Mark, Nevoux, Marie, Prévost, Etienne, Chaput, Gerald, Du Pontavice, Hubert, Guitton, Jérôme, Sheehan, Timothy, Mills, Katherine, Rivot, Etienne
• Other Authors: Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Université de Pau et des Pays de l'Adour (UPPA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Fisheries and Oceans Canada (DFO), Northeast Fisheries Science Center (NEFSC), NOAA National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), Gulf of Maine Research Institute (GMRI), The research leading to these results has received funding from the Agence Française de la Biodiversité under grant agreement INRAe-AFB SalmoGlob 2016–2018. The study was part-funded by the European Regional Development Fund through the Interreg Channel VA Programme, Project SAMARCH Salmonid Management Round the Channel
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: hierarchical Bayesian model; climate change; stage-based life cycle model; marine survival; bottom-up; environmentally driven changes; Spatial covariation; Atlantic salmon; [SDE.MCG]Environmental Sciences/Global Changes; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Norwegian Sea; Labrador Sea; North Atlantic; Salmo salar
• Online Access: https://institut-agro-rennes-angers.hal.science/hal-02613874; https://institut-agro-rennes-angers.hal.science/hal-02613874v2/document; https://institut-agro-rennes-angers.hal.science/hal-02613874v2/file/Olmos_et_al-2019-Global_Change_Biology%281%29.pdf; https://doi.org/10.1111/gcb.14913

A major challenge in understanding the response of populations to climate change is to separate the effects of local drivers acting independently on specific populations, from the effects of global drivers that impact multiple populations simultaneously and thereby synchronize their dynamics. We investigated the environmental drivers and the demographic mechanisms of the widespread decline in marine survival rates of Atlantic salmon (Salmo salar) over the last four decades. We developed a hierarchical Bayesian life cycle model to quantify the spatial synchrony in the marine survival of 13 large groups of populations (called stock units, SU) from two continental stock-groupings (CSG) in North America (NA) and Southern Europe (SE) over the period 1971-2014. We found strong coherence in the temporal variation in post-smolt marine survival among the 13 SU of NA and SE. A common North Atlantic trend explains 37% of the temporal variability of the survivals for the 13 SU and declines by a factor 1.8 over the 1971-2014 time series. Synchrony in survival trends is stronger between SU within each CSG. The common trends at the scale of NA and SE capture 60% and 42% of the total variance of temporal variations, respectively. Temporal variations of the post-smolt survival are best explained by the temporal variations of sea surface temperature (SST, negative correlation) and net primary production indices (PP, positive correlation) encountered by salmon in common domains during their marine migration. Specifically, in the Labrador Sea/Grand Banks for NA populations 26% and 24% of variance is captured by SST and PP, respectively and in the Norwegian Sea for SE populations 21% and 12% of variance is captured by SST and PP, respectively. The findings support the hypothesis of a response of salmon populations to large climate induced changes in the North Atlantic simultaneously impacting populations from distant continental habitats.