Le saumon face au changement climatique

International audienc

L'adaptation au changement climatique des populations exploitées de saumon

National audienc

Conditionnement des stratégies d'histoire de vie et mécanismes adaptatifs à court terme : approche intégrée par capture-marquage-recapture et application au saumon atlantique (Salmo salar) en condition naturelle

Diplôme : Dr. d'Universit

Investigating the ecological impacts of salmonid invasions: a meta-analytic approach at the global scale

International audienc

Adaptation et persistance des populations de saumon face au changement climatique

International audienc

Conditionnement des stratégies d'histoire de vie et mécanismes adaptatifs à court terme : approche intégrée par capture-marquage-recapture et application au saumon atlantique (Salmo salar) en condition naturelle

Diplôme : Dr. d'UniversitéUnderstanding the origin of life history variations of organisms requires studying life history strategies and evolutionary processes that drive them. This thesis aims at studying life history strategies under natural conditions and how they are conditioned by individual characteristics. Life history strategies are seen as a combination of reaction norms and evolutionary trade-offs. The study of evolutionary processes in the wild faces to methodological issues. Indeed, the exhaustive monitoring of individuals over time is often impossible in the wild. Capture-mark-recapture methods allow a partial observation of life histories and life history traits. This work was based on the idea that our observations are only the visible part of underlying processes that need to be accounted for to limit the risk of flawed statistical inferences. I resort to hidden structure modeling to 1) separate the observation process from the dynamic process of interest, 2) model the full life histories of individuals, 3) integrate within a single and coherent framework life history decisions and evolutionary trade-offs and 4) explicitly represent the underlying mechanisms that generate our observations. Within this framework, one can confront theories and concepts in evolutionary biology with observational data through appropriate statistical tools. Finally, I illustrate this work by studying the conditioning of life-history strategies in a natural population of Atlantic salmon on the Scorff river (Morbihan) using CMR data. My results highlight status- dependent life history decisions and evolutionary trade-offs that could not be identified without our proposed modeling framework.Pour comprendre l’origine des variations d’histoire de vie des organismes, il faut étudier et mettre en évidence les stratégies d’histoire de vie et les processus évolutifs qui les gouvernent. Ce travail de thèse a pour objectif d’étudier les stratégies d’histoire de vie et leur conditionnement par les caractéristiques individuelles en conditions naturelles. Les stratégies d’histoire de vie sont vues comme un agencement de normes de réactions et de compromis évolutifs. Cependant, l’étude des processus évolutifs en milieu naturel se heurte à des problèmes d’ordre méthodologique. En effet, le suivi exhaustif au cours du temps d’individus d’une population est difficilement réalisable, voire impossible en conditions naturelles. Les méthodes de capture-marquage-recapture permettent une observation partielle des histoires de vie et des traits d’histoire de vie. Ce travail se base sur l’idée que nos observations ne sont que la partie visible de processus sous-jacents qu’il est nécessaire de prendre en compte pour ne pas biaiser nos inférences statistiques. J’utilise la modélisation à structure cachée pour 1) séparer le processus d’observation du processus dynamique d’intérêt, 2) modéliser les histoires de vie complètes des individus, 3) intégrer dans un cadre unique et cohérent les décisions d’histoire de vie et les compromis évolutifs et 4) représenter explicitement les mécanismes sous-jacents qui génèrent nos observations. Dans ce cadre, on peut alors intégrer les théories et concepts de la biologie évolutive dans l’analyse statistique des données d’observations. J’illustre ce travail par l’étude du conditionnement des stratégies d’histoire de vie dans une population naturelle de saumon Atlantique sur le Scorff (Morbihan) à partir de données de CMR. Mes résultats mettent en évidence des décisions d’histoire de vie statut-dépendantes et des compromis évolutifs qui n’auraient pas pu être mis en évidence hors du cadre de modélisation proposé

Can we predict the fate of Atlantic salmon populations in the face of climate change?

International audienceAtlantic salmon Salmo salar is the subject of many management actions aiming at their conservation. There is a strong demand, expressed by a diversity of local to international bodies for assessing the consequences of climate change for this species relative to the conflicting objectives of both conservation and exploitation. However, our predictive ability is still limited by the complexity and uncertainty of current and future environments, complexity of the life cycle and especially by the challenges of teasing apart evolutionary change from more 'plastic' responses to environmental perturbation. I discuss the importance and complementarity of experimental research, long-term monitoring in natura and modeling approaches. Importantly, life cycle models provide a powerful tool for disentangling eco-evolutionary processes and investigating interactive, synergistic effects among multiple factors in order to better understand the eco-evolutionary responses of populations in the face of various scenarios of climate change. I will present a demo-genetic Individual-based model which is designed to investigate the demogenetic consequences of environmental change scenarios on an exploited population of Atlantic salmon. Without omitting its limits, I show how this approach allows to synthesize knowledge and to identify its gaps

Can we predict the fate of Atlantic salmon populations in the face of climate change?

International audienceAtlantic salmon Salmo salar is the subject of many management actions aiming at their conservation. There is a strong demand, expressed by a diversity of local to international bodies for assessing the consequences of climate change for this species relative to the conflicting objectives of both conservation and exploitation. However, our predictive ability is still limited by the complexity and uncertainty of current and future environments, complexity of the life cycle and especially by the challenges of teasing apart evolutionary change from more 'plastic' responses to environmental perturbation. I discuss the importance and complementarity of experimental research, long-term monitoring in natura and modeling approaches. Importantly, life cycle models provide a powerful tool for disentangling eco-evolutionary processes and investigating interactive, synergistic effects among multiple factors in order to better understand the eco-evolutionary responses of populations in the face of various scenarios of climate change. I will present a demo-genetic Individual-based model which is designed to investigate the demogenetic consequences of environmental change scenarios on an exploited population of Atlantic salmon. Without omitting its limits, I show how this approach allows to synthesize knowledge and to identify its gaps