Résumé: The CLIOTOP (mid‐trophic automatic acoustic sampling) project and the EurOcean consortium are organizing a workshop in May 2011 in Bergen, Norway. The presentation will summarize the discussions and conclusions from the workshop. The workshop will deal with the technological and modeling issues related to the mass deployment of acoustic sensors in the open ocean environment. The technological challenges that will be addressed are plans and concepts for novel platforms carrying acoustics and complementary techniques, energy supply and consumption, and data transfer technology. Presently, acoustics cannot provide measures of the species‐specific biomass of all taxa, and complementary technologies and ecosystemmodels need to be tailored to the available data. The modeling part of the workshop will focus mainly on the model‐data links. It will cover the topics required to design a large scale observational system and to improve the combination of models and observations through data assimilation. The use of acoustic data in marine ecosystemmodels is indeed often done in a fairly naive way, typically by assuming that acoustic measurements can provide acute and precise estimates of biomass. This leads to underestimated uncertainty and potentially biased results which need to be rigorously addressed in appropriate state‐space frameworks.