نشریه پژوهش های علوم و فنون دریایی
سال دوازدهم شماره 4 (زمستان 1396)

This study aimed to investigate on species diversity of elasmobranches in the Iranian waters of the Persian Gulf (Hormozgan province) and Oman Sea, and length- weight relationships for dominant species were estimated. For this purpose, samples were collected using both industrial-research bottom trawlers of using“Ferdows” class ship and shrimp trawlers by-catch, between May 2014 and September 2015. A total of 709 individuals, belonging to 28 elasmobranch species (19 batoids from 11 families and 9 sharks from 5 families), were collected and studied. Between the species of batoids, seven species were dominant, including Torpedo sinuspersici (107 individuals), Himantura randalli (99 individuals), Gymnura poecilura (77 individuals), Brevitrygon imbricata (79 individuals), Rhinobatos punctifer (68 individuals), Pastinachus sephen (46 individuals) and Aetobatus flagellum (17 individuals), while among sharks, five species, including Iago omanensis (63 individuals), Rhizipriondon acutus (47 individuals), Carcharhinus macloti (35 individuals), R. oligolinx (17 individuals) and Chiloscyllium arabicum (18 individuals) were dominant in the sampling region, for which length –weight parameters were estimated. In general, most species showed positive allometric or isometric growth. Also, both the disk length-weight and disk width-weight relationships showed a good fit, indicating the credibility of these factors for investigating the length-weight relationships.

Nowadays, increasing public concern have challenged the environmental problem associated with wastewater. Indeed, the removal of contaminates from wastewater is still far away from a satisfactory solution. Different processes are used for the treatment of wastewater. However, adsorption on activated carbon can be an environmentally friendly and economically sound process. In this study, olive-waste activated carbon as was employed as a novel adsorbent for efficient removal of lead (heavy metals). In the removal process the variables; pH, concentration of lead, amount of adsorbent and contact time, were studied on their influence on removal of lead, using one at a time approach, in a batch procedure on removal of lead which used 109 mg/g. Following the investigation of concentration effect, fitting the experimental equilibrium data to numerous conventional isotherm models showed that the Langmuir model with high correlation coefficient and low error analysis (R2=0.998) is more usable to explain the experimental data. The kinetic models were studied and parameters of this model was calculated. First order kinetics was predicted for adsorption with 0.99 error tolerance.

The increase of organic and inorganic compounds in the river basin of the south coastal area of the Caspian Sea has been exacerbated by intensification of the Eutrophication process. In order to provide some useful data for planning of coastal management, the trophy of the chlorophyll a, total phosphorus and total nitrogen were determined. The result of measuring three limnologic parameters (chlorophyll a, total phosphorus and total nitrogen) for a period of 11 months, were entered into the geographic information system during the spring of 2013 to February 2014. By determining the position of ten stations in south coast of the Caspian Sea, in Gilan province, from Khosk-Rood to Astara, their trophy status in terms of chlorophyll a, total phosphate, total nitrogen, as well as TSI index were determined. Based on the results of this study, among the three effective factors of trophic in the studied areas, in winter, the highest correlation was found between total phosphorus and total nitrogen of 47%. The annual survey showed a correlation between phosphorus and total nitrogen of 87%, followed by correlation between chlorophyll a and nitrogen of 56%. The results showed that, 39 and 61 percent of south coastal areas in Gilan province were oligotrophic and mesotrophic, respectively. The normal curvecomparison of total phosphate based on OECD standards, indicated a trend in coastal change from oligotrophic to mesotrophic, which can be a threat to the region

Fish is one of the most significant and valuable food resources that plays an important role in nutraceutical foods and is the most important source of polyunsaturated fatty acids (PUFA), in particular n-3 fatty acids. Increasing fish consumption is the only realistic way to increase the beneficial PUFAs and to create more favorable W-6: W-3 in the human food diet. The objective of this project was to determine the fatty acid composition of the muscle tissue of three species of brackish water fish, carp fish, white fish and beluga. In all three types of fish, oleic acid (C18:1c) concentration was the highest. The highest levels of PUFA found in beluga and white fish was linoleic acid (C18:2c) and in carp fish, docosahexaenoic acid (C22:6). The results showed that the saturated fatty acid in the studied species were 47, 50.2, 24.45 percent respectively. The results for PUFAwas 8.9, 15.9, and 40.73 percent and finally for MUFA were 45.6, 34.4, and 34.9 percent of total fatty acids, respectively. The W6:W3 ratio in these fish species was 0.64, 0.74, and 2.99 respectively. The total amount of fatty acids was analyzed using GC/MS and results were statistically analyzed using analysis of variance method (one - way ANOVA). No significant difference was observed among three studied species of fish (P>0.05). In all three species the unsaturated fatty acid levels were higher than the saturated fatty acid levels and according to their W6:W3 ratio, all three species are considered to be valuable sources of nutrition.

Persian Gulf waters remain heavily impacted by a number of pollutants originating from different sources such as direct and indirect discharge of land based pollutants, sewage etc. Millions of tons of industrial effluents are dumped into the gulf shallow waters every year and the environment is highly contaminated in many urban and industrialized areas of many countries. As a result, high concentrations of heavy metals occur in some areas.The aim of the present study is to determine the bioaccumulation of heavy metals such as lead in water, sediment, soft and hard tissues of Euchelusasper at four selected stations of Kish Island’s rocky shores in winter and summer of 2014. Lead in water samples were assayed (after preparation and chemical digestion) using Perkin Elmer 4100 atomic absorption spectrometer. Lead heavy metal concentrations obtained in four stations in winter and summer, respectively, in soft tissue were 2.57 ppb and 2.02 ppb, in hard tissue 2.28 ppband10,1 ppb, in sediment 2.23 ppb and 1.73 ppb and in water, lower than detection limit.

Blood parameters often are used as indicator for stress and health condition evaluation in fishes. The aim of this study was to compare the blood and biochemical indices between stellate sturgeon (Acipenser stellatus) and Common Carp (Cyprinus carpio). In total, 20 brood stock fish (including 10 of each species) were selected and blood samples were taken. Results showed that mean levels of red blood cells (RBC), white blood cells (WBC), haematocrit (Hct), hemoglobin (Hb), cholesterol and osmolarity in Common Carp were more than Stellate sturgeon and showed no significant difference (P>0.05). Differential count of leucocytes showed that mean level of lymphocytes percent in A. stellatus was more than C.carpio, whileneutrophile, Eosynophile and monocyte in C.carpio were morethan A. stellatus with no significant difference (P>0.05). Mean level of Glucose in C.carpio was significantly more than A. stellatus (P<0.05). Mean levels of triglyceride, albumin and total protein in A.stellatus was significantly more than C.carpio (P<0.05). Cytomorphological parameters of RBC such as cell area, nucleus area and MCV in A.stellatus was significantly more than C. carpio. The results indicated that the levels of some blood parameters were different between stellate sturgeons (Acipenser stellatus) in comparison with Common Carp (Cyprinus carpio) which can be related to their difference in development levels.

One of the most important effects of wave entrance to the shallow waters and sea bed topography on them in coastal zone is wave breaking phenomenon. This process is a crucial factor in production of cross-shore, rip and longshore currents that are generally introduced as near shore currents. In this research, longshore currents of Amirabad area were considered and then the most appropriate relation was obtained for computation of velocity for these kind of currents. In addition, pattern of the currents were obtained using the field data of waves and currents By using the hydrographic map of the study area and also the slope of the shore and using the data from the buoy in Amirabad station and wave rose fitted coefficient in Amirabad area, velocities of longshore currents were computed in experimental terms. The computed results were then compared (using MATLAB software) with velocities of currents measured by flow meter, to estimate the most compatible selected relationship and fitted coefficient term. The results showed that, the average of velocity of longshore current in Amirabad shore is 16cm/s and dominant direction of current is eastern.

This study intends to evaluate the accumulation of heavy metals such as lead and cadmium in the edible tissue of whitefish in Anzali Lagoon and comparewith international standards of FDA and FAO. Whitefish were caught from the west, central and east regions of Anzali Lagoon. Sampling was conducted in the fall season. Levels of heavy metals were measured using flame atomic absorption spectrometry. The average concentration of cadmium in whitefish from center of wetlands was 0.05 μg/g, in western and eastern parts of wetland was 0.03 μg/g dry weight, respectively. There was no significant difference (P> 0.05) in the levels of cadmium in different parts of the lagoon. The average concentration of lead in whitefish in the western parts of wetlands was 0.33 μg/g, in central and eastern parts 0.53 and 0.41 μg/g dry weight, respectively. No significant difference (P> 0.05) was noticed in the lead levels in different parts of the lagoon. Pb in central region of wetland showed no significant increase compared with international standards. Cd concentration in all parts of the lagoon was within the range of international standards