Mesopelagic Southern Ocean Prey and Predators The underlying concept of MESOPP is the creation of a collaborative network and associated e-infrastructure (marine ecosystem information system) between European and Australian research teams/institutes sharing similar interests in the Southern Ocean and Antarctica, its marine ecosystem functioning and the rapid changes occurring with the climate warming and the exploitation of marine resources. While MESOPP will focus on the enhancement of collaborations by eliminating various obstacles in establishing a common methodology and a connected network of databases of acoustic data for the estimation of micronekton biomass and validation of models, it will also contribute to a better predictive understanding of the SO based on furthering the knowledge base on key functional groups of micronekton and processes which determine ecosystem dynamics from physics to large oceanic predators. This first project and associated implementation (science network and specification of an infrastructure) should constitute the nucleus of a larger international programme of acoustic monitoring and micronekton modelling to be integrated in the general framework of ocean observation following a roadmap that will be prepared during the project.