Quantifying heritable and plastic components of age at maturation in Atlantic salmon and predicting response to selection by fisheries

• Main Author: Favreau, Aurélien
• Other Authors: Institut Agro Rennes Angers, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut Agro Rennes-Angers, 65 rue de Saint-Brieuc, 35042 Rennes, Didier Gascuel, Rémi Patin, Étienne Rivot
• Format: Master Thesis
• Language: English
• Published: HAL CCSD 2022
• Subjects: Salmo salar; Population dynamics; Heritability; Plasticity; Maturation; Modelling; Bayésian; Dynamique des populations; Héritabilité; Plasticité; Modélisation; Bayésien; [SDV]Life Sciences [q-bio]; Atlantic salmon
• Online Access: https://dumas.ccsd.cnrs.fr/dumas-03868105; https://dumas.ccsd.cnrs.fr/dumas-03868105/document; https://dumas.ccsd.cnrs.fr/dumas-03868105/file/2022_Favreau_Aur%C3%A9lien_SHA.pdf

Wild populations of Atlantic salmon (Salmo salar) have experienced a decline in abundance in recent decades, accompanied by changes in important phenotypic traits such as time spent at sea. Time spent at sea before reproduction is known to be highly heritable but also environmentally influenced. Separating the plastic and heritable component in this evolution becomes essential to quantify the influence of multiple pressure factors such as changes in the marine ecosystem or fishing. We propose a Bayesian state-space model to separate the plastic and heritable components of the temporal variability of the age at maturation of a salmon population in the Scorff River. By adapting a parent-offspring regression we can successfully estimate the heritability of the probability of maturation after one year at sea using a model based on population data. The plastic response, which can thus be distinguished from the heritable component, then explains only part of the variability of the trait. By integrating the breeder’s equation into the model, we can both derive empirically evolutionary equilibrium and predict short-term response to the selection under several fisheries scenarios. In a context where fishing and/or the environment encountered during marine migration can generate differential mortality between the ages of the sea, these results constitute a first step to predict the consequences in terms of population dynamics and evolution of life traits at the population level. Les populations sauvages de saumon atlantique (Salmo salar) ont connu un déclin de leur abondance dans les dernières décennies, accompagné par des changements dans des traits phénotypiques importants comme le temps de séjour en mer. Ce temps passé en mer est connu pour être fortement héritable mais aussi sous influence de l'environnement. Séparer ces deux composantes devient alors essentiel pour quantifier l’influence de multiples facteurs de pression comme les changements dans l’écosystème marin ou la pêche. Nous proposons un modèle Bayésien à ...