Some ecological indices of the Caspian Sea Amphipoda at the different depths Guilan offshore

In the present study, some ecological factors were studied for Amphipoda at different depths. The Shannon, Margalef, and Hill indices were used to determine the  species diversity, richness and evenness, respectively. In addition, the association and niche overlap values were estimated. Indices of species richness and diversity were highest at 50 and 100m depths, respectively.  The ordination of depths show that the highest dissimilarity was at 20m depth and the lowest dissimilarity at 100 meter.  Results of interspecific association and specific overlap of species show that only a few species could have similar ecological requirements. Results show that Paraniphargoides derzhavini with Niphargoides grimmi and Stenogammarus compersus with Amathilina  cristata  had low associations.  Corophium spinulosum with Corophium nobile and Stenogammarus compersus with Paraniphargoides derzhavini, however, had high associations.