Invasive species are a general issue common of every seas in the world. Impacts of biological invasion on the food web of the Wadden Sea will be figure out through 3 related positions (Sarina Jung, PhD student ; Camille de la Vega, PhD student ; Ulrike Schueckel, Post doctoral student) included in the INFOWEB project. To investigate the impact of invasive species on the food web, a good comprehension of the trophic relation and energy fluxes between the different compartments of the food web is essential. Food webs will be portrayed for three different parts of the Wadden Sea (Jade Bay, Sylt-Römö Bight, Balgzand) using Ecological Network Analysis and the influence of invasive species on trophodynamics will be estimated. Different habitats homing different species communities have been already described, for examples, “Arenicola flat”, “sea grass bed” or “mussel bed”. According to these habitats, several models will be built. The first steps of these three studies will be to collect the missing data needed to build the model: biomass, respiration, egestion, production and diet composition for each species or compartments of the food web. The diet composition will be estimated with the method of stable isotopes coupled for the high trophic level with stomach content analysis.