Évaluation comparative des traits d'histoire de vie dans les communautés de petits poissons pélagiques des systèmes côtiers à haute productivité

Small pelagic fish (SPF) communities are a central link in marine food webs. Moreover, they account for 20% of the global catch. These populations are abundant in the boundary upwelling systems (Humboldt, California, Canary, Benguela Currents) where they are subject to strong variations in abundance. These changes are strongly linked to recruitment variations and environmental “bottom-up” forcing, which makes their dynamics difficult to predict. To better understand the mechanisms underlying these fluctuations, we propose to compare the life history traits of the most abundant species in these systems as well as the characteristics of their habitat that may underlie the observed dynamics. In this framework, the Ph.D. thesis I recently started proposes the development of a generic model of the life cycle of SPF based on DEB theory. Comparison of the same species in different habitats or close species in the same system is an approach that appears promising to limit the uncertainty around the estimated parameter sets. We also aim, in a second objective, to better reconstruct the inter-individual variability in these populations by linking otolith (fish ear bones) formation, to our SPF-DEB model. In this context, the mineral and organic fractions of the otolith are considered as metabolic products linked to the growth and dissipation transformations. This otolith growth module will be coupled with Lagrangian simulations to compare the observed and simulated variability of otolith patterns (size, opacity, and shape). This study will contribute to a better understanding of the variability of individual responses to environmental factors