The study of effects of Sturgeon pen culture on distrubtion, abundance and biomass macroinvertebrate in Gorgan Gulf

Nowadays, the environmental impact of fish culture on water quality and benthic macroinvertebrates is known as pollution water. Therefore the studies were carried out to determinate of distribution, abundance and biomass value macro invertebrate around Sturgeon pen culture in Gorgan Gulf. Seasonal samplings were carried out from August 2015 to July 2016. The study was done at 5 stations in 3 transects, where three pen culture were active. Stations were in distance 0, 5, 25, 50 and 100 m far from pen. Benthos was collected using a van Veen grab (20*25 cm). Density, abundance percent and biomass were calculated for groups. Totally, 11 genus's and 10 families belong to 3 phyla as Mollusks, Arthropods and Annelids were identified. The results showed, there were the maximum abundance percent belong to Pyrgulidae (Hydrobiidae) and Cochliopidae with 33.83% and 26.05% and the minimum abundance percent belong to Gammaridae with 0.05% respectively. However, the maximum abundance belongs to Pyrgohydrobia sp., from Pyrgulidae with 3410 n/m2. The results showed, there were the maximum and minimum abundance in autumn and spring with 3263n and 2044n respectively. So, there were the maximum and minimum abundance of benthic in 3 and 1 stations with 2469 n and 1821 n respectively. Finally, there were no significant difference on abundance and biomass macroinvertebrate around Sturgeon pen culture in Gorgan Gulf (p>0.05).