BIONOMY OF MACROBENTHIC MOLLUSKS IN EVROS DELTA (NORTH AEGEAN SEA)

The composition and distribution of the macrobenthic molluscs in Evros Delta (North Aegean Sea) were investigated by quantitative sampling. The molluscan distribution shows a zonation mainly related to the degr ee of ''confinement''. Based on similarity in distribution among stati ons, 2 groups of species were distinguished. One group includes marine species (Tellina tenuis, Bittium reticulatum) found only in coastal s tations and the second group is typical of estuarine species (Hydrobia acuta, Abra ovata and Cerastoderma glaucum) distributed in almost all stations. Spatial fluctuations of the 3 estuarine species reflect the ir preferences in the various parameters (''confinement'', salinity, g ain size and organic matter of sediment). The most isolated stations s upport the highest values of total mollusc abundance and biomass.