Valuable marine habitats and living resources can be found in the Eastern English Channel and in 2003, a Franco-British Interreg IIIA project, ‘Eastern Channel Habitat Atlas for Marine Resource Management’ (CHARM), was initiated to support decision-making for management of essential fish habitats. Fish habitat corresponds to geographic areas within which ranges of environmental factors define the presence of a particular species. Habitat Suitability index (HSI) modelling was used to relate fish geographic distribution and their relation towards environmental factors and to delineate their optimum habitat. This study was based on data obtained from 1988-2003 IFREMER’s Channel Ground Fish Surveys, including both species abundance and environmental data. Suitability index (SI) functions based on generalised additive models were used to relate depth, temperature, salinity and sediment to sub-community assemblage probability of occurrence. As a result, SI values were positively related to assemblage affinity along the gradient of the environmental variables. The resulting HSI models were used to map, using GIS, the optimum habitats of communities ; sensible habitats such as spawning grounds, nurseries or areas carrying bio-diverse fish community were also defined. The information obtained will help to elaborate guidelines for the conservation and protection of natural habitats in the face of climate change and anthropogenic disturbances.