Search

International audience; The study tests the physiological responses of Persian sturgeon, Acipenser persicus, during the abrupt release of juveniles from freshwater (FW) into brackish waters (BW=11 parts per thousand) of the Caspian Sea. Fish weight at release was 2-3g (2.55 +/- 0.41g; 8.8 +/- 0.58cm TL). Totals of 160 individuals were randomly distributed into four fiber-glass aerated tanks (volume 60-L). Two tanks served as controls (FW groups), and two as exposure tanks for BW (Caspian Sea water=CSW). Fish were sampled at 0, 3, 6, 12, 24, 48 and 96hr after abrupt transfer to CSW. Plasma osmolality, immunolocalization of Na+, K+ -ATPase (NKA) and Na+/K+/2Cl(-) (NKCC) Co-transporter, NKA activity and the NKA -subunit mRNA expression were analyzed. Blood osmolality of fish transferred from FW to CSW increased significantly within hours post-transfer (p

Present study carried out between September 2011 and October 2012 in 19 sampling sites in order to investigate the trophy level, productivity, and natural dominant living conditions in the Gorgan Bay. According to the provided maps from the shoreline, depth, and sediment, the total area and volume of Gorgan Bay is 466 square meters and 905.33 million cubic meters respectively. Also the physic-chemical parameters including: water temperature, EC, salinity, transparency, DO, BOD5, pH, Ammonia, Nitrate, Total hardness, Total alkalinity, and phosphate are determined and studies. 3 main phylum, 12 orders, 6 classes, and 12 families from bottom living organisms (macro-benthos) were identified in this region. Standard deviation in TSI was from minimum 37 in March up to maximum 65 in September and the annual average was 53. According to the average TSI in different months, for five months namely as March, April, June, August, and February the dominant situation was eutrophy. For the rest of months namely as May, September, October, November, December, and January the dominant situation was Meso-trophic in the Bay. Based on calculation, minimum and maximum productivity in the Bay were 92.26 and 700.66 Kg per hectare in October and July respectively. The annual average of productivity was 195.10 Kg per hectare. Iranian Fisheries Science Research Institute Published

The Caspian salmon S. trutta caspius in respect to its reproductive life cycle has two immigrant forms namely fall-run and spring-run. As the Shahid Bahonar center activities on Caspian salmon stocks restoration in Klardasht of Iran has been just focused on fall-run form propagation, it could be proposed that these stocks proportions have been gradually increased. Regarding to lack of information on genetically differences between the two groups, in this study, genetic structure of these immigrant forms were analyzed by using 5 microsatellite loci. Results revealed that the most allelic frequencies were observed in fall-runs. Average of observed and expected heterozygosity in fall-runs and spring-runs were, 0.7719, 0.6108 and 0.4435, 0.5911, respectively. In both groups except Str543INRA in spring runs, all loci had deviation from Hardy-Weinberg equilibrium. Furthermore except Str543INRA in spring runs, expected heterozygosity in all loci was more than observed heterozygosity. Genetic distance between two populations and Fst, as a population distinctive index, were 0.081 and 0.025, respectively. In conclusion 5 microsatellite loci used in this study show low genetic differentiation between fall-runs and spring-runs