آب لب شور

A comparison of fatty acid levels of rainbow trout reared in brackish water and freshwater in the southern region of the Caspian Sea was done using four types of commercial feed. The fish with equal density and biomass were reared for 90 days. The fish weight was 500 g at the first of rearing, and they reached more than 1700 g at the end of the breeding period. To determine the fatty acid profile, 5 samples from each farm were taken from the dorsal muscle of the edible tissue of fish at the end of the rearing period. The results showed that the rearing environment, in addition to affecting fish growth and feed efficiency, also affected the meat composition of the fatty acid profile of fish meat. The maximum weight gain of the fish in freshwater was 1025 g, and in brackish water was 1291 g with a food conversion ratio of 1.27-1.32 and 0.97-1, respectively (p<0.05). The feed efficiency rate was obtained in fresh water 1.07-1.97 and in brackish water 2.29-2.59 (p<0.05). The total saturated fatty acids of fish in freshwater (22.24±1.07%) was lower than in brackish water (25.69±0.22 %) (p<0.05). The total of monounsaturated fatty acid and polyunsaturated fatty acids differed in farms independent of diet and rearing environment (p<0.05). However, the amount of omega-6 fatty acid was optimal (17.52-31.26%), and omega-3 fatty acid (0.10-0.12%) was far less than similar studies outside Iran. As a result, a small amount of omega-3 unsaturated fatty acid was used in the composition of the primary ingredients of the feed. Generally, the growth process, feed efficiency, and meat of rainbow trout raised in brackish water in a sea cage environment has relatively better quality than fish raised in freshwater.

This research aimed to enrich Artemia nauplii with Easy DHA and Espresso to improve the growth and survival of vannamei shrimp post larvae and transfer them to brackish water (Caspian Sea). 2100 vannamei shrimp post-larval with an approximate average weight of 49.54 ± 2.60 mg and an average length of 1.09 ± 0.07 cm (PL8) were selected. For each replication, 50 vannamei shrimp post-larval were randomly placed in forty-two 20-liter glass tanks (containing 15 liters of water) and were distributed indoors. Post-larvae were fed, including freshly hatched Artemia, Artemia enriched with Easy DHA and espresso, and commercial diet for ten days (in salt water and desalination water). The highest growth rate (weight and length) in the saltwater group was observed in treatment seven (P < 0.05). Also, the highest survival rate in this group was observed in group three, with 71% (P < 0.05). Among the treatments of the brackish water group, the highest growth rate (weight and length) was observed in group fourteen (P < 0.05). The highest survival rate was observed in treatments of nine, ten, and thirteen (P < 0.05). Post larvae of the sea and brackish water showed the highest amount of fatty acid C20-5n3 in treatment three and fatty acid C22-6n3 in treatment two (P < 0.05). Based on the present study's findings, enrichment of Artemia with Easy DHA and Espresso and feeding post larvae with it for nine days can increase survival and resistance to stress (transition to lower salinities) in vannamei shrimp post larvae.

Water quality management in brood-stock tanks, especially in terms of water salinity and water hardness, is of great importance to the reproductive performance of the crustaceans. The sodium absorption ratio (SAR) is a compound formula that has a ratio of sodium ion to total calcium and magnesium ions of water. The purpose of this study was to investigate the effects of different ratios of sodium to total calcium and magnesium of (SAR) in water on reproductive indices of female freshwater prawn. For this study, 12 tanks of 80 liters were assigned to 4 treatments with 0, 5, 10 and 15 sodium absorption ratios, each with 3 replicates. After the 60-day period of experiment, different reproductive indices were measured. The results indicated that the egg clutch somatic index (ESI) and the dry weight of eggs were significantly higher in treatment of sodium absorption ratio 5 than other treatments. Fertilized eggs percentage and hatched eggs percentage in control and 5 treatments were not significantly different but decreased with increasing of sodium absorption ratio in 10 and 15 treatments respectively. While different levels of sodium absorption ratio in water had no significant effect on total and relative fecundity parameters. Larval status index was significantly higher in treatment of sodium absorption ratio 5 than other treatments. Finally, the SAR at female brood-stock tank water can be optimized to achieve the highest reproductive performance and produce the best quality larvae. Therefore, it is recommended that the authorities of the reproductive centers that do not have natural brackish-water should adjust the water absorption ratio to 5 when making brackish-water for hatchery centers.

An experiment was conducted to evaluate the effects of stocking density on growth and survival of Nile tilapia (Oreochromisniloticus) in brackish water earthen pond. Fish with initial weight of 13 g kept in three stocking density 3, 6 and 9 fish/m2 in duplicates and were fed on rainbow trout feed for 105 days during the light period. The results showed significant reduction in final weight, weight gain, daily growth rate, specific growth rate and survival by increasing stocking density, while feed conversion ratio enhanced in higher stocking densities (p

In this study, the effects of different primary stocking densities (45, 50, 55 and 60 shrimp/m2) of whiteleg shrimp postlarvae (PL12) were evaluated on the growth and survival rates. Brackish water (10.52±0.43 psu) was provided from the Caspian Sea. The experiments were performed in 12 circular concrete ponds with a sandy bed (area: 78m2) with four treatments and three replications for each treatment. The culture period was 75 days and the average water temperature was 27.4±1.79°C. The results showed that different stocking densities caused statistical significant difference in growth and survival rates among various experimental treatments (P

Litopenaeus vannamei (Boone, 1931) post-larvae 12 were obtained from Bushehr province and reared at the Caspian Sea Ecological Research Iinstitute (Mazandaran, Iran) in summer 2012 using brackish water of the Caspian Sea. Prior to start of the experiment, post-larvae were gradually adapted to brackish water. The shrimp was stocked in a 1000 m2 earthen pond with a stocking density of 31 individual/m2. The earthen pond was in quarantine without discharge valve. During the rearing period, there was no water exchange. The shrimp was reared for 85 days. The average daily growth, final mean weight, feed conversion ratio and final yield were 0.31±0.04 g, 21.11±0.71 g, 0.79 and 531 kg, respectively. The results showed that L. vannamei can growth well in brackish water of Caspian Sea (salinity of 11.1±0.7 ppt and temperature of 28.67±0.72 °C) in Mazandaran province from July to September.

In this research, controlled changes of rainbow trout muscular composition cultured in brackish water (14.1ppt) and freshwater (4.3ppt) was compared. Some 180 juvenile rainbow trout with a weight of 47.2±0.1g each were released in 6 polyethylene tanks with a capacity of 1.5m³. During the experiment, water temperature was kept constant. Feeding fish was conducted using common Faradaneh food and considering water temperature and fish biomass. After 126 days, fishes attained around 320±20g of weight, were sampled and taken to laboratory and the amount of protein, fat, ash, minerals and moisture in their muscle tissue were measured. Results showed amount of fat and dry matter in brackish water cultured fishes is less than those cultured in freshwater. The average percentage of protein and minerals in brackish freshwater cultured fishes were significantly different and the average percentage of moisture in brackish water cultured fish was higher than those of the freshwater fish.

Culture of beluga (Huso huso) in new conditions such as inland brackish water necessitates studying nutritional requirements and effects of different diets on gonadic and somatic growth as well as physiological condition. In this research 74 beluga each 4 years old cultured in brackish water of earthen ponds in Bafgh Fisheries Research Station, were selected and distributed in 8 circular cement ponds. Feeding was done in 4 formulated diets with fixed protein level and 4 energy levels (400, 425, 450, 475kcal/100g). Samples were biopsied at the start and the end of the experiment to determine sexuality and stage of maturation. To study gonad tissues, the hematoxylin-eosin method was used. Results indicated that somatic and gonadic growth indices were affected by diets. Somatic growth overlapped in both sexes. Sexual maturation stages were not the same in males and females and trarisition from stage II in males was more rapid than females. Considering the results in this study, diet treatments influenced on somatic growth in both sexes and gonadic growth in females. We conclude that somatic and especially gonadic growth in brackish water is suitable. Therefore, inland brackish water environment can be regarded suitable for beluga cultivation.

Sampling in 5 stations was carried out from July 1999 to June 2000. Water temprature, pH and EC were measured on site. Maximum water temprature was observed in July and August, and maximum level of dissolved oxygen occured in November and February. Range of pH was between 7.2 to 9.4, in acceptable range for aquatics. The results showed that Shadegan marsh is a hard and brackish water body. Dissolved oxygen level was more than 5 ppm in most of the cases, and is optimum for fish growth and reproduction. Amount of BOD5 was 3-10 ppm. COD levels showed an increase in Autumn. With respect to N.NO3 and N.NO2, the water could be considered as unpolluted water. According to the statistical analysis of data, Mansoreh and Ataysh stations showed the same water quality. Study in various years showed that water quality in Shadegan Marsh has been diminished, probably due to decreasing run off and increasing pollution in Shadegan Marsh.