The Impact of Bluga(Huso huso) cages on water abiotic factors in the southern part of Caspian Sea(Jafroud region)

According to the climatic, ecological and hydrological conditions in the Caspian Sea and according to the Caspian Sea is an enclosed inland body of water and habitats for many valuable aquatic species and endangered sturgeons, it is necessary that comprehensive studies are conducted before any development on fish culture in the sea. This project was financially supported by the Fisheries Organization of Guilan Province and was conducted in the International Sturgeon Research Institute in order to investigate abiotic factors for sturgeon cage culture in Jafroud region of Anzali Port (depth of 50 m) for one year. Physico-chemical factors were investigated monthly. The investigations were carried out in four stations in cage and one station outside the cage (20 m in the opposite direction of water flow in the west). The abiotic conditions for fish cage culture including physico-chemical factors (temperature, dissolved oxygen concentration, pH, salinity as well as nitrite, nitrate, orthophosphate, electric conductivity and total Suspended Solids (TSS) were measured monthly. physico-chemical factors in rearing cage significantly did not affected (p<0.05) growth rate of Huso huso. Also results obtained from this study revealed that there were no significant differences between parameters inside and outside of the cage (p<0.05). However, significant effects of variations in TSS, Total Organic Matter (TOM) and grain sediments factors levels were observed in inside and outside of the cage (p<0.01).The results of abiotic factors found around the stations are in the range of the allowable concentrations of theses parameters for culture. Considering to the environmental findings, the results of this study provides the useful information for fish culture to manage well based on the water quality and hydrological foreseen. The results from this study can enable managers to obtain necessary data to evaluate the rearing capacity of fish in marine cage to issue the permits for sturgeon culturists.