International Journal of Farming and Allied Sciences Available online at www.ijfas.com ©2016 IJFAS Journal-2016-5-7/491-502/ 31 Dec, 2016 ISSN 2322-4134 ©2016 IJFAS Ecological Relationships between Biotic and Abiotic parameters within the establishment of Fish Farming Cage Culture in the southern Caspian Sea Mohammadali Afraei Bandpei*; Hassan Nasrollahzadeh Saravi; Aboulghasem Roohi; Farokh Parafkandeh; Nourbakhsh Khodaparast; Houriyeh Younesipour; Abdolla Nasrolahtabar; Alireza Keihansani Caspian Sea Ecology Research Center, Iranian Fisheries Science Research Institute, Agricultural Research Education and Extension Organization (AREEO), Sari, Iran Corresponding author: Mohammadali Afraei Bandpei ABSTRACT: This research examines the abundance and biomass of biota factor with the relation of some physicochemical parameters at the fish cage culture in the southern Caspian Sea (Kelarabad- Mazandaran, Iran) in 2013 to 2015. Seasonal sampling was conducted at three stations, station1 (fish cage site), station 2(at a distance of 500 m west), and station 3 (at a 50 meters east of the fish cages). The aims of this study were to investigate the relationship between the density and biomass of phytoplankton, zooplankton and macrobenthos and the concentration of some heavy metals and petroleum parameters. A total of 38 species of phytoplankton, 6 species of zooplankton and 7 species of macrobenthos were identified. The results showed that the highest concentration of DON and DIN was recorded in winter which showed a positive correlation between phytoplankton and nutrients. At the present study, the abundance and biomass of phytoplankton showed reduced in the spring but in contrast the density and biomass of zooplankton was highest which would be due to full feeding of predators, zooplankton. Comparison of Polycyclic Aromatic Hydrocarbons (PAHs) at different seasons showed that the highest amount was detected in spring and the highest concentration of Anthracene and Fluoranthene was in autumn. The results showed that the amount of pollutants in the Caspian Sea was less than the standard limited. There was not significant differences between petroleum amounts in various seasons (P>0.05). The environmental parameters analysis showed that 5 to 20 meter depths were considered as sensitive areas and a depth of 5 and 10-20 meter divided on two groups that represent the interactions between biotic and abiotic parameters on each other's activities. Keywords: Biotic and abiotic groups, fish cages, Kelarabad, Caspian Sea INTRODUCTION Breeding fish in the sea to spread globally and although plenty of marine products for human consumption provides a mutually pressure on food supplies entering [33]. Caspian Sea due to its geographical location, unique resource of plants and animals, including sturgeon (Acipenseridae), bony fish (Cyprinidae) and Kilka fish (Clupeidae) has a great importance that any change in the Caspian Sea ecosystem will affect the creatures [14, 3]. Physicochemical variety of Situations River leading to the sea due to the entry industrial waste and sewage plants, urban and rural communities and changes the biotic and abiotic the Caspian Sea. Other factors like entry the new species from the Black Sea into the Caspian Sea e.g. Mnemiopsis leidyi [12, 39], climate changes and ballast water made changes the diversity and density of phytoplankton species [27] and zooplankton [40]. The adverse