摘要：The Gulf of Arzew, northwestern Algeria, constituting one of the biggest petroleum area in the world, is one of the most polluted region in the Mediterranean Sea. A good way to know the degree of this pollution that undergoes this region is to assess the number of living pollution sensitive species. Consequently, the mollusks populations seem to be a good indicator of the intensity of this pollution. For this purpose, it has been recorded a certain heterogeneity in the distribution of mollusks species and one found low densities in the different Twin analyses which seems to be due to the progression of the mud in some stations in one hand and the impact of pollution from the industrial area in the second hand. This set of species is, therefore, characterized by a stable installation of muddy species. However, in all Twins, has been reported the appearance of a transition zone, consisting of a mixture of sand and vases and characterized by low diversity where species muddy dominate.
关键词：Mollusks; pollution; Gulf of Arzew; biodiversity.
