BIONOMY OF MACROBENTHIC POLYCHAETES IN THE EVROS DELTA (NORTH AEGEAN SEA)

The composition and distribution of the macrobenthic polychaete fauna in the Evros Delta (Noah Aegean Sea) have been investigated by means o f 4 replicate quantitative samples collected at 35 sites. 10 species w ere found and, in additional qualitative samples, the sedentary specie s Ficopomatus enigmaticus was collected. On the basis of the similarit y in distribution among stations, 3 groups of species have been distin guished. One of these groups includes the species Spio decoratus and H ediste diversicolor which were both dominant and present at almost all stations. The distribution of species in the study area seems to depe nd on factors such as salinity, granulometric composition and organic matter of the sediment and interspecific competition, but mainly on th e degree of ''confinement'', namely the degree of exchange with the op en sea. At the most isolated stations, the lowest number of species an d the highest values of abundance and biomass were recorded.