Effect of Sewage Effluent on Macro-invertebrate Assemblages on Rock and Cement Boulders in Mazandaran Province, Southern Caspian Sea

Abstract

This study compared colonization of rock and cement boulders by sessile organisms along sewage polluted and partially polluted shores in the southern Caspian Sea. The macro-invertebrates were sampled using a 225 cm2 (15 × 15 cm) quadrat (N = 3) from 9 natural and 9 cement boulders in polluted and partially polluted shores. A total of 59120 individuals of macro-invertebrates were counted and assemblages were numerically dominated by molluscs with 789.4 ± 197.3 (mean ± standard error), followed by arthropods with 96.6 ± 26.8 and annelids with 5026 ± 1934.5. There were no significant differences in number of species, assemblages of macro-invertebrates and mean density between sewage polluted and partially polluted shores on natural and cement boulders in the southern Caspian Sea.