Journal of Aquatic Ecology

 Barnacles are most important macro benthic population of Rocky shores that Amphibalanusimprovisus is a dominant invasive species of this group. Present study aims to define the number, biomass, coverage rate and to study the factors affecting on the distribution of this species in various parts of rocky shores of south Caspian Sea. Ten sampling stations were selected in the natural and artificial rocky shores from Astara to Babolsar and during two years and every 2 months, once from September 2013 to July2014. In general, the mean number of individuals in this species in the coasts was 404.75 271.165, coverage rate was 36.83 19.657, and weight was 17.81 11.825g in unit surface. While relatively even distribution results are displayed in 10 Stations. But in one-way ANOSIM grouping it was noted that most similarity of habitat was related to the stations 3, 4,5,6,9 and results of One-way ANOVA in various months indicated that temporal changes do not dramatically effect on the frequency of Amphibalanusimprovisus. In addition, it was defined that salinity of southern coasts have not effect for growth of barnacles and temperature was an important and positive factor in frequency.