Cycle annuel du peuplement macrobenthique du port d'Alger

The impact of pollution on the macrobenthos was studied through a seasonal cycle by analysis of samples taken at 34 stations in the different basins of Algiers harbour (Mustapha, Agha and Vieux Port). Physical and chemical characteristics were measured in the water column (temperature, salinity, seston, dissolved oxygen) and sediment (pH). The faunistic composition of the stations was assessed according to the ecological significance of species or groups of species as determinants of pollution. There were close correlations between the physical and chemical characteristics at che stations and the spatial distribution of species and species assemblages. Seasonal variation in populations was most marked in Mustapha basin, less noticeable in Agha and weak in the Vieux Port. The benthic population was always more degraded in the inner 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 Algiers, to the innermost part of the docks, in Mustapha, which are macroscopically azoic.