Evaluation écologique des eaux marines côtières de Mostaganem par l’utilisation de la macrofaune benthique

Abstract

The coastal strip of Mostaganem is part of the coasts polarized by human activities which have negatively affected marine ecosystems, thus becoming fragile, weak and limited areas. Through these problems on the coasts, we have highlighted in this thesis the evaluation and the identification of benthic macrofauna present in the coasts of Mostaganem, by choosing three sites with different human activities (Stidia, Kharouba and Khadra). And to know the abundance of these organisms along the coastal strip of the areas studied. The results revealed that the Khadra site contains a large abundance of benthic macrofauna (13,229 individuals, including a total of 20 identified species) with an abundance of Molluscs. The third station of this site witnessed the greatest biological diversity. Followed by the Stidia site with 3082 individuals, and 19 species in total, in which the mollusc abundance was 81%. To complete and verify the results, we used the sea urchin Paracentrotus lividus, as a bio-indicator, by calculating the rates of fertilization of eggs and the development of larvae by incubating them in different media. The results revealed that the rate of fertilization of eggs reached 90% in each of the three sites studied. And that after 72 hours, the results showed that there was a difference in the shapes of the larvae obtained and that the sand of the Kharouba site gave the highest percentage of abnormal larvae during the incubation of the fertilized eggs of sea urchins P. lividus of Kharouba origin.