The impact of hydrography on the vertical zonation of the zooplankton community was studied in the Bornholm Sea. A total of 832 vertically stacked multinet samples were used for the analysis. By means of multivariate discriminant function and canonical analysis we show a distinct separation of the zooplankton community. Three main habitats, reflecting the hydrographic situation, were identified with characteristic differences in zooplankton composition: 1) The summer surface layer, bounded by the thermocline at its lower rim. Species of this layer are only seasonally abundant or forced to adjust to the cooler winter water beside the warm season. 2) The intermediate winter water, bounded by the halocline below and the thermocline or surface above. Species dwelling in this layer face a reduced volume and are cut off from the high primary production when their habitat is compressed by wrm summer waters. 3) The layer between the permanent halocline and the sea floor. The taxonom ic composition of this layer showed no significant effect in relation to observed inflows. Five different utilisation strategies of the dominant zooplankton species were identified from these three habitats. Based on the results we discuss the impact on trophodynamic interactions and advective processes.