Several habitats (subtidal and intertidal soft substrates, saltmarsh creeks, etc.) are present within the Scheldt estuary. This complex system can function as spawning ground, nursery area, feeding ground and/or pathway in diadromous migrations for several fish and crustacean species. During the 1990s several studies were performed on (post)larval, juvenile and adult fish and macro-crustaceans, both in the WesterScheldt and in the ZeeScheldt. The different life history stages and subhabitats required specific sampling strategies and they were sampled during different periods. This makes it difficult to compare studies. This presentation is a compilation on the significance and role of selected habitats in the life cycle of the dominant fish and macrocrustacean species in the Scheldt estuary. Both habitat availability and habitat use are quantified. The importance of estuarine biotopes as habitats for fish is evaluated through a Habitat Utilisation Index. Data on species diversity and seasonal and spatial differences in growth and abundance are presented. Both short and midterm patterns can be related to changes in the environment. Next to the ecological guilds, also feeding guilds are used to assess the relationship with the lower consumers. A generalised food web structure within the Scheldt estuary is proposed, which illustrates the importance of mysids and other small crustaceans in the food of juvenile fish and shrimps. An impression is given on the gaps in our knowledge about the nursery function of the Scheldt ecosystem.