فصلنامه اقیانوس شناسی
پیاپی 23 (پاییز 1394)

In this investigation, concentration of the organochloric agricultural poison Lindane was measured in the muscle of three fish species including Kutum, Common carp and Golden gray mullet in eight stations located in the southern shore of the Caspian Sea (Bandar Torkaman, Khazarabad Sari, Fereydunkenar, Chalous, Kiashahr, Bandar Anzali, Hashtpar and Astara). In each station, fishes were caught randomly. Lindane extracted and chemical analysis using gas chromatography supplied with electron capture detectors (GC-ECD), has been done. Results showed that average amounts of Lindane in Kutum, Common carp and Golden gray mullet were 1.88 ±1.65, 1.83 ±1.41 and 1.60 ±1.48 ng/g in fresh weight, respectively. Chalous (3.16 ±1.43 ng/g fresh weight) was the most contaminated station in terms of Lindane contamination. The reslts showed that the amount of Lindane had a declining trend in recent years.

The major aim of this study was to investigate the effect of Genistein on the histological structure of three spot Gourami''s (Trichogaster trichopterus). Six groups of immature fish were injected intramuscularly by 0. 15، 1. 5 and 15 mg/kg of Genistein and by the same doses of 17β-estradiol (E2). The sham group was received ethanol and control group was remained intact. After the end of treatment، the fish''s ovaries were investigated histologically via H&E staining method. The statistical test of pairwise Tukey was applied on the average diameter of oocyte among all groups. The results showed significant difference between groups that were treated by Genistein (0. 15 mg/kg)، E2 0. 15 mg/kg، and the control group (P<0. 001). Subsequently، the Mann Whitny test was also applied on the number of oocytes of each fish''s ovary. The results exhibited significant difference between groups whom they treated by Genistein (0. 15 and 15 mg/kg and control group (P<0. 001). Histological observations demonstrated that the Genistein in (0. 15 mg/kg) dose had estrogenic effect and increased the development rate of oocyts in ovary، whereas Genistein in dose (15 mg/kg) verified anti-estrogenic effect. On the other hand، 17β-estradiol in (15 mg/kg) dose caused delay in the development of oocytes and increased the number of atretic oocytes dramatically. On the contrary، treating by 17β-estradiol of (0. 15 mg/kg) dose was accelerated the oocytes development. These outcomes of our experiment proved that Genistein could have dual effects (estrogenic and anti-estrogenic) based on its dose. Besides، treating by E2 at higher dose may cause delay in the oocyte development.

In this research، genetic stock assessment of Hilsa shad Tenualosa ilisha was undertaken from natural distribution of species including rivers and southern coasts of Khuzestan، Bushehr and one sampling area from western coast of Malaysia as an outgroup. For this purpose، analysis of MtDNA genome of D-loop region was carried out for 86 samples of Hilsa shad. Then amplified fragments were automated sequenced and genetic analysis was done using genetic softwares including BioEdit، MEGA and Arlequin. Results showed that there were several subpopulations of Tenualosa ilisha at least in Khuzestan waters including rivers، estuaries and marine areas. In addition، the minimum Fst (Fst= 0) was in Khuzestan selected sites while maximum Fst (Fst =0. 64) was observed in Bushehr and western coast of Malaysia. Phylogenetic analysis showed that Hilsa shad samples originated from western coasts of Malaysia represents higher levels of genetic differentiation compared to subpopulations of this species inhabited in Iranian waters. However، both Malaysian and Iranian Tenualosa ilisha occupy the same place on phylogenetic tree.

Wave induced pressure variations on rubble mound breakwater are important to enable correct designing of this structure. Because of its effect on the hydraulic stability of armor layer، hydraulic interactions and water surface elevation inside the breakwater، the importance of investigating the effect of wave induced pressure on the structure will be cleared. Due to the complexity of wave breaking interaction with a porous rubble mound breakwater، calculating the pressure on the structure is not possible by using analytical methods. In this paper، a simple physical argument by using maximum depth-integrated momentum flux in a wave as it reaches the toe of the structure was used to derive a formula to calculate the pressure variation on rubble mound breakwater. The results showed a good estimation of wave pressure variation on the rubble-mound breakwaters by using wave momentum flux parameter for regular and irregular waves. Also، it can be concluded that the wave dynamic pressure has a dominate contribution in a total depth-integrated wave momentum flux.

To study the air-sea heat flux climatology over the Caspian Sea, the net heat flux and its components including solar radiation, long wave radiation, latent heat and sensible heat fluxes were calculated for the period of 1985 to 2009. The bulk formulas were applied to re-analysis data set to calculate the heat fluxes. The annual net heat flux for this period was estimated as -0.69 Wm-2. The magnitude of this value regardless of its sign showed that the basin is in the equilibrium state. The variation trend for the 25 years revealed that from 2002 onward, the basin loses more energy. In the seasonal scale, the basin gain energy in spring-summer and loses energy in fall-winter. The 25 years average evaporation of the basin was estimated as 1128 mm yr-1 with increasing trend after 2003.

The effects of salinity on density of A. tonsa at three salinity treatments include 9 ±1, 11 ±1 and 12 ±1 psu (Mean±SE) and two experimental water temperatures of 25 ±2 and 23 ±2oC were investigated in the present study. Treatments were examined with three replicates inside a 250 cc tanks over a two weeks period trials. Data showed animals grew to copepodites after two days. The first group of experiments with Acartia tonsa cultured at 23 ±2oC and 12 ± 1psu. The results of this study showed that about 24-39% of the animals grown and has completed in the tenth to twelfth days to copepodites and reached to sexual maturity. After 16 days, about 68% of the initial nauplii reached sexual maturity. The second group of experiments with Acartia tonsa cultured at 21 ±1oC and 11 ±1 psu. The results showed that after 15 days, nauplii grew to adult and also the adults have spawned within 15th days. The results of this research showed that the appropriate salinity and temperature for A. tonsa were 12 psu and 25oC, respectively.

Methods of estimating the remaining life of cracked tubular joints in offshore jacket-type platforms are based on fracture mechanics (FM) approach. The accuracy of FM approach depends on the accurate estimation of the stress intensity factors (SIFs). In the present paper, effects of geometric parameters on the results of SIFs for tubular X-joints are investigated. In this study, FE models were generated using ABAQUS and to evaluate the SIFs, J-integral method was used. Numerical SIF results were validated against available experimental data. Results showed that the J-integral method is suitable for the calculation of SIFs. The increase of the γ (= D / 2T) and/or β (= d / D) leads to the decrease of the SIFs. Moreover, the increase of the τ (= t / T), c / a ratio and/or a / T ratio results in the increase of the SIFs; where D, d, T, t, a, and c are the chord diameter, brace diameter, chord thickness, brace thickness, crack depth, and half of crack length, respectively.

In this study, the concentration of Pb, Cd and V in the shell of (Saccostrea cucullata) and surface sediments were measured in the intertidal zones of Lengeh Port. Therefore, sampling of Saccostrea cucullata (48 samples) and sediment (15 samples) from 3 coastal stations along Lengeh Port were conducted in 2010 fall. Samples were digested by direct aqua regia method after drying. After that, chemical analysis of the sediment and the oyster samples were done by using Atomic Absorption Spectrophotometer (Shimadzu AA-670). Result of the analysis stated that: the mean values of Pb, Cd and V in the sediment were in order 163.02 ±4.04, 1.26 ±0.05 and 0.028 ±0.001 (µg g-1dw), respectively and in the shell of oyster were in order 124.38 ±1.81, 5.09 ±0.19 and 0.018 ±0.001 (µg g-1dw). In comparison with global standards, Pb levels exceed from the permissible limit, however Cd and V levels were found suitable for the sea foods. In general, with respect to the results obtained, it was found that the shell of S. cucullata is a suitable biomonitor for monitoring Pb and V levels in the area.

In this study, wave was simulated in the southern part of Caspian Sea using nested grids of SWAN model and utilizing ECMWF-ERAI wind data. Wave model was verified with the correlation of %94 comparing the modeled and measured data at Neka, Nushahr and Anzali stations. The simulations were repeated utilizing wind data used in ISWM II. Although, wind data used in ISWM II have been verified in the Caspian Sea, the higher spatial resolution of ECMWF-ERAI wind data resulted in a better prediction of the wave periods up to 1s and wave heights up to 0.5-1.5 m in the east and central parts of the southern Caspian Sea. However, the results of SWAN using ECMWF-Reanalysis INIO wind data were in a better agreement with the trend of measurements in west part of the Caspian Sea. Also, wind data used in ISWM II resulted in higher accuracy prediction of wave characteristic for measured wave heights less than 1.5 m.

The goal of this study was histological and morphometrically changes of liver and intestine in spotted grouper, because they are two important tissues for developing. After feeding larva with designated rations every five days, liver and intestinal tissue were removed and performed by standard and routine tissue procedures. Sections were stained with H&E and PAS and were examined under light microscope. Microscopic. The morphometric studies showed that the area of the hepatocytes, long and diameter of villi increased as larval developing. But the greatest changes in area of the hepatocytes were observed from six weeks to the end of the larval period. The most changes on villi long were seen 35 to 60 days after hatching, and maximum diameter changes were seen three weeks from the time of hatching. Development of liver and intestinal tract in normal grouper fish larvae have a pattern similar to other teleosts, but there was some differences in terms of time differentiation and organ function among different species that depends on the life history and a number of genetic, environmental factors and nutrition.