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The aim of this study was to investigate the environmental impacts of fish cage culture on some biological and non-biological parameters. The study area in Mazandaran Province has been located in two cage fish farming centers in the cities of Klarabad and Abbas Abad in south of Caspian Sea. Each center had four circular polyethylene floating cages of 2500 cubic meters (20 meters in diameter and 8 meters in height). The initial storage rate of rainbow trout for each cage was 5 tons or 20,000 pieces with a weight range of 240-260 grams. The final harvesting rate of each cage was 15 tons with a weight range of 700-900 grams.The fish cage culture was carried out for 5 months (late December 2014 to mid-May 2015). The sampling was carried out in January and March 2014 and in May and august 2015 around the cages (shadow cage, 50 meters, 100 meters and 1000 meters) in three geographical directions (east, west and south). Sampling was maked of biological organisms (macrobenthos, plankton and bacteria) and non-biotic parameters (water and sediment). In this study, water quality index, trophic level index, biological indices of planktonic and macrobenthos were determined and analyzed. The results showed that there were no definite and regular changes influenced by fish farming on the cage environment in the two sites of klar Abad and Abbas Abad. It seems that this situation can be attributed to the hydrological conditions of the area, the low volume of fish culture, the short fish culture period, the proper depth of water for the establishment of cages and turns and currents water, especially in different directions. Therefore, the sites were used for the first fish culture period, the accumulation of nutrients around the cages did not change immediately in the ecosystem structure of these areas. Of course, there were changes in biological organisms and non-biological parameters during different sampling periods, which was the result of seasonal changes and environmental conditions in the area. Therefore, it is recommended that an environmental impact assessment be carried out for fish cage cultur in large scale farms or farms with several culturer experiences. Published

The aim of this study was to investigate the environmental impacts of fish cage culture on some biological and non-biological parameters. The study area in Mazandaran Province has been located in two cage fish farming centers in the cities of Klarabad and Abbas Abad in south of Caspian Sea. Each center had four circular polyethylene floating cages of 2500 cubic meters (20 meters in diameter and 8 meters in height). The initial storage rate of rainbow trout for each cage was 5 tons or 20,000 pieces with a weight range of 240-260 grams. The final harvesting rate of each cage was 15 tons with a weight range of 700-900 grams.The fish cage culture was carried out for 5 months (late December 2014 to mid-May 2015). The sampling was carried out in January and March 2014 and in May and august 2015 around the cages (shadow cage, 50 meters, 100 meters and 1000 meters) in three geographical directions (east, west and south). Sampling was maked of biological organisms (macrobenthos, plankton and bacteria) and non-biotic parameters (water and sediment). In this study, water quality index, trophic level index, biological indices of planktonic and macrobenthos were determined and analyzed. The results showed that there were no definite and regular changes influenced by fish farming on the cage environment in the two sites of klar Abad and Abbas Abad. It seems that this situation can be attributed to the hydrological conditions of the area, the low volume of fish culture, the short fish culture period, the proper depth of water for the establishment of cages and turns and currents water, especially in different directions. Therefore, the sites were used for the first fish culture period, the accumulation of nutrients around the cages did not change immediately in the ecosystem structure of these areas. Of course, there were changes in biological organisms and non-biological parameters during different sampling periods, which was the result of seasonal changes and environmental conditions in the area. Therefore, it is recommended that an environmental impact assessment be carried out for fish cage cultur in large scale farms or farms with several culturer experiences. Iranian Fisheries Science Research Institute Published

The aim of this study is the feasibility of introducing suitable species of fish (native and exotic) for rearing in cages in the southern region of the Caspian Sea. This study from the perspective of economic efficiency and maintaining ecology were analyzed. The results showed that the southern Caspian Sea has the ability to aquaculture fish. However, due to the yearly temperature variations of water (from surface to a depth of 50 meters), the talent of aquaculture area is preferred for fish in cold water than warm water fish due to possibility rearing over the years. The survey showed that the current conditions and due to unfavorable changes in the ecology of the area in the last decade, the use of non-native fish culture in cages is not recommended. Many species of native fish are suitable for rearing in cages. Nevertheless, there is no infrastructure suitable for the production of all of them. Therefore, respectively species of Salmo caspius, Huso huso and Common carp of Caspian Sea for cultivation of in cages was suggested. In the current situation, this fish for their ability to grow faster than the need for selectivity. It is noteworthy that detailed environmental assessments and species risk assessments before the final introduction of any fish species (native and exotic) for rearing in cages in the Caspian Sea ecosystem is essential.

In this research was used sodium chloride in feed supplement to stimulate ion- osmotic regulation system of Rutilus Kutum juveniles (about one gram) in fresh water environment.The purpose of this experiment was to improve survival and growth ability of juveniles’ fish in brackish water during times of transition. The initial average weightes of Juveniles’ fish were 0.91±0.01 g (mean±SE). Experiments carried out in two phases. In step one, the Juveniles’ fish were kept for 15 days in fresh water and fed with commercial diet plus NaCl supplement (control without NaCl supplement, 5, 7 and 10 percent) in four treatments, each treatment inclusive three replication. In the second step, the fish transferred to brackish water (12.5 psu) and fed for 28 days with a commercial diet (without NaCl supplement). The results showed that no change compared to control treatment in renal tissue in step one. The difference between the kidneys were not in fish fed with NaCl supplement and without it. Nevertheless, a significant difference was observed between the size of the glomeruli and renal tubules between fresh and brackish water environments (between stage one and two), (P0.05). The results showed that the fish fed dietary supplements of sodium chloride 10% versus the control treatment had less weight gain. Therefore, the was obtained the highest weight gain and growth performance (condition factor, specific growth rate) and the highest feed efficiency and protein efficiency ratio and the lowest feed conversion ratio in treatment 2 with the feeding of 5% NaCl in dietary supplements. Iranian Fisheries Science Research Institute Published

The aim of this study is the feasibility of introducing suitable species of fish (native and exotic) for rearing in cages in the southern region of the Caspian Sea. This study from the perspective of economic efficiency and maintaining ecology were analyzed. The results showed that the southern Caspian Sea has the ability to aquaculture fish. However, due to the yearly temperature variations of water (from surface to a depth of 50 meters), the talent of aquaculture area is preferred for fish in cold water than warm water fish due to possibility rearing over the years. The survey showed that the current conditions and due to unfavorable changes in the ecology of the area in the last decade, the use of non-native fish dulture in cages is not recommended. Many species of native fish are suitable for rearing in cages. Nevertheless, there is no infrastructure suitable for the production of all of them. Therefore, respectively species of Salmo caspius, Huso huso and Common carp of Caspian Sea for cultivation of in cages was suggested. In the current situation, this fish for their ability to grow faster than the need for selectivity. It is noteworthy that detailed environmental assessments and species risk assessments before the final introduction of any fish species (native and exotic) for rearing in cages in the Caspian Sea ecosystem is essential. Iranian Fisheries Science Research Institute Published

Recently, the development of aquaculture has focused on the use of seawater, because of freshwater crisis in the world. Whiteleg shrimp (Litopenaeus Vannamei) is one of the most important species for aquaculture development, because of tolerance and adaptation to different ecological conditions. One of the advantages of species in aquaculture, compatibility status is dense in the rearing period. In this study, the effect of different densities (45/m2 , 50/m2 , 55/m2 and 60/m2 ), of primary stock whiteleg shrimp postlarvae (PL12) on the growth and survival rate were evaluated. Brackish water (10.52±0.43 ppt) was providing from Caspian Sea. The experiments were performed in 12 circular concrete pond with a sandy bed (area: 78m2 ) in four treatments and three replications for each treatment. The experiments performed in a 75-day period. In this study, the water temperature was 27.4±1.79°C. The results showed statistically difference in growth parameters and survival rate among experimental treatments (Duncan test, P

Recently, the development of aquaculture has focused on the use of seawater, because of freshwater crisis in the world. Whiteleg shrimp (Litopenaeus vannamei) is one of the most important species for aquaculture development, because of tolerance and adaptation to different ecological conditions. One of the advantages of species in aquaculture, compatibility status is dense in the rearing period. In this study, the effect of different densities (45/m^2 , 50/m^2 , 55/m^2 and 60/m^2 ), of primary stock whiteleg shrimp postlarvae (PL12) on the growth and survival rate were evaluated. Brackish water (10.52±0.43 ppt) was providing from Caspian Sea. The experiments were performed in 12 circular concrete pond with a sandy bed (area: 78m^2 ) in four treatments and three replications for each treatment. The experiments performed in a 75-day period. In this study, the water temperature was 27.4±1.79°C. The results showed statistically difference in growth parameters and survival rate among experimental treatments (Duncan test, P

The survey effect of salinity, turbidity and dissolved oxygen performed on Rutilus frisii Kutum juveniles with aim, which was determined about survival rate and histological changes in gill and kidney tissues. Juveniles provided from the Rajai's fish propagation center and then examined in Caspian Sea Ecology Research Center laboratory. The juveniles were investigated on three weight group (200-75%) had shown in 400