MACROBENTHIC COMMUNITIES IN ALGIERS HARBO R

The impact of pollution on the macrobenthos was studied through a seas onal cycle by analysis of samples taken at 34 stations in the differen t basins of Algiers harbour (Mustapha, Agha and Vieux Port). Physical and chemical characteristics were measured in the water column (temper ature, salinity, seston, dissolved oxygen) and sediment (pH). The faun istic composition of the stations was assessed according to the ecolog ical significance of species or groups of species as determinants of p ollution. There were close correlations between the physical and chemi cal characteristics at che stations and the spatial distribution of sp ecies and species assemblages. Seasonal variation in populations was m ost marked in Mustapha basin, less noticeable in Agha and weak in the Vieux Port. The benthic population was always more degraded in the inn er part of the docks than in the outer basins. There is a very strong gradient of degradation from the northern entrance of the Vieux Port, where the macrobentic community is similar to that of the Bay of Algie rs, to the innermost part of the docks, in Mustapha, which are macrosc opically azoic.