فصلنامه اقیانوس شناسی
پیاپی 5 (بهار 1390)

Khuzestan coastal waters in the north west of the Persian Gulf were examined between 2006 to 2007 to investigate the juvenile fish fauna. Samples were caught using a 360 hp research vessel towing and a 24 mm mesh size bottom trawl. 64 species categorized in 40 families were recorded. The most frequent species were Thryssa vitriostris; Leiognathus bindus; Ilisha compressa; Penahia macrophthalmus; Johnius belangerii comprised 80% of total juvenile fish frequency. 41 species was caught during July (highest species total number). Increasing trend in total number of fishes was observed during April to July. Highest diversity index and lowest dominance index was found in July. Correlation analysis indicated that water salinity is most important environmental factor corresponds with total number of species fluctuations. Results of this study in accordance with previous researches confirmed the role of coastal waters as nursery grounds for juvenile fishes.

The polycyclic aromatic hydrocarbons (PAHs) are pollutants of concern due to their persistent in the marine ecosystem, and their cause long-term adverse effect to the marine life. In this study, of concentrations of 14 PAHs and their sources in the rocky shore oysters (Saccostera cucullata) and in the sediments of boushehr province were determined. The rocky shore oyster was selected due to its wide distribution and its role in the diet of Boushehr coastal area. The sampling and analysis were perfprmed in july 2009. Samples were collected from four rockyshore stations, Genaveh, Boushehr, Dayer and Nyband Gulf. Collected samples were immediately transferred to hexane rinsed glass jars with aluminum foil inserts and transported in dry ice to the laboratory of PGRSC and kept frozen at -20°C prior to analysis. An aliquot of the samples were taken for dry weight determination. The tissue was dried with anhydrous sodium sulphate and soxhlet, then extracted for about 8 hours using dichloromethane: hexan (1:1v/v). The extract was then charged to 1st step and 2nd step column chromatography to fractionate hydrocarbons.The sediment samples were extracted with the same method, except using dichloromethane for soxhlet extractor. The fractions were analyzed by gas-chromatography/mass spectrometry (GCMS). The recovery of PAHs were more than %65. The total concentration of PAHs in oysters ranged from 146.9 to 268.1 ng/g Dry weight, while sediment concentration ranged from 41to 227.6 ng/g dry weight. Boushehr rockyshore oyster that did not present very high levels of contamination expressed low PAHs ratio. Total lipid in station 2 was higher than others. The significant correlation was observed between total lipid and total PAHs p ≤ 0.05. Both pyrolitic and petrogenic PAH are present in all oyster and sediment samples.

The Tajan River is one of the important rivers in the southern Caspian Sea and it is too important for migration of some fish species, feeding and spawning of estuary fishes and resident fish population. Main purposes of this study were Environmental Effects of Shahid Rajai’s Dam on species diversity of fishes in Tajan River from March 2008 to July 2009. Two stations have been selected in up and down of Shahid Rajai Dam and fishes captured by electroschoker. Results showed that 9 species and subspecies fish belonging to 4 families: Cyprinidae, Nemacheilidae, Cobitidae and Gobiidae exist in the river so that Cyprinidae with 6 species and maximum abundance (95%) is prevalent. On the identified fish species, Alburnoides bipunctatus and Capoeta capoeta gracilis were the most abundant, respectively. In this study, Luciobarbus capito only one specimen was caught in May 2009. The Shannon Diversity Index and Richness Index were significantly different between sites (P<0.05), but Evenness Index and Dominance index were no significantly different between sites (P>0.05). Results show that construction of this dam has had great impact on physical and chemical properties and on also biological effects of the river.

This study reviews the relationship between biochemical compounds of coelomic fluid (sodium, potassium, magnesium, calcium, cholesterol, total protein and glucose) and some biological characteristics of gonad (egg and biological properties of egg and gonad weight), fertilization success rate of egg and size of larvae in Kutum (Rutilus frisii kutum). For this purpose, in spring 2007, 48 specimen females with a mean length of 49.62 ± 1.2 cm and weight of 977 ± 229 g (without calculating gonad weight) from the Tajan River captured and these relationships were examined. This study showed that there was significant correlation between K+ and perivitelline space (P<0.05) while there was an inverse significant correlation between K+ and yolk sphere to perivitelline space ratio (P<0.05). There was significant correlation between Mg 2+ and gonad’s weight (P<0.05). There was an inverse significant correlation between Na+ to K+ ratio with number of eggs in one gram of ovulated gonad (P<0.05) while there was a significant correlation between Na+ to K+ ratio and Ca2+ to potassium ratio with larval size in second biometry (P<0.05). There was also significant correlation between total protein and diameter of the hydrated eggs (P<0.05). There were significant correlation between glucose and diameter of egg, surface and volume and perivitelline space and there was inverse significant correlation between glucose and surface to volume ratio (P<0.05).

Geochemical studies of sediments, water bodies like rivers, estuaries and the sea bed can be an effective step to find the sources and distribution model assessment environmental pollutants in a region. Sediments where the accumulation of heavy metals in aqueous environments, but under special conditions can act itself as a source of water pollution. Entrance of heavy metals in different ways, causing many risks such as cancer, poisioning and etc in organisms. To study heavy metals in the Gorganrud in 10 stations, a core and surface samples were taken. Fine-grain sediments were used to determine heavy metals (Al, Cr, Ni, Cu, Fe, Co, Mn) concentration, using the method of inductivity couple plasma. Comparison of metal concentration in surface sediments to the deep sediments of the study area was done by enriched factor. The average of total concentration were determined, respectively, Al> Cr> Co> Fe> Ni> Mn> Cu. The results showed that values are close to 1 which is the effect of natural factors and watershed drainage basin on heavy metal enrichment. Coefficients of low-enriched heavy metals are resulted mainly from erosion of natural resources (watershed) which human activity is negligible. However, higher values were observed in station 1 representing the effect of human factors in this region. Therefore, it should be noted that it still needs attention to consider environmental management.

Preliminary investigation of calcareous nannofossil assemblages of surface sediments gathered from large area across the Iranian coast of Persian Gulf was carried out in order to improve the interpretation of paleontological data passed on planktonic group. In this study, Gephyrocapsa oceanica and Emiliania huxlyi are the dominant taxa in all stations. In the distribution pattern of the assemblages, not only the 2 mentioned species but also other species of nanoplanktons (or seasonal minor taxa) were observed. The occurrence of reworked species from Cretaceous- Neogene strata were observed in the assemblages.

The purpose of this study was to find important criteria and sub-criteria for artificial reefs site selection for conservation of coral reefs in the Kish Island coastal areas (the Persian Gulf). This study was carried out using Delphi questionnaire and Analytical Hierarchy Process (AHP) methodology. We reviewed papers, which were related to the aim of the study. Four main criteria (physical environment, biological environment, managerial and socio-economical factors) and 32 sub-criteria were found to be important in stability of the coral reef ecosystems. The selected criteria and sub-criteria were re-assessed by 9 experts using a Delphi questionnaire. Subsequently, 13 sub-criteria (water depth, distance from natural reefs, water temperature, bottom slope, distance from polluted areas, competitive species, turbidity, natural larval supply, salinity, bottom type, currents, distance to ship waterways and economical advantage of reefs establishment) out of four main criteria were selected as the final subcriteria for artificial reef site selection in coastal areas of the Kish Island. In order to obtain relative weights and prioritization of the final criteria and sub-criteria, pair-wise comparisons were used (by Expert Choice 11). According to AHP, the weights of main criteria (physical, biological, managerial and socio-economical factors) were 0.553, 0.287, 0.122 and 0.038, respectively. Also, the weights of final 13 sub criteria were 0.153, 0.151, 0.091, 0.083, 0.081, 0.077, 0.073, 0.058, 0.056, 0.051, 0.046, 0.042 and 0.038, respectively. The results of the present study showed that physical environment and water depth were the most important criteria and sub–criteria, respectively, for selecting a site to construct artificial reefs in the Kish island coastal areas.

The Effect of starvation interrals on hematological factors including hemoglobin, hematocrit, red (RBC) and white blood cell (WBC) count and corpuscle indices (MCV, MCH, MCHC) of Siberian sturgeon, Acipenser baeri, with an initial body weight of 19.71±0.83g was studied in a flow-through rearing system. After adaptation for one week to experimental conditions, 15 experimental fish were randomly distributed each in twelve 500L fiberglass tanks and were subjected to 4 different feeding regimes: C, control (fed four times daily); T1 (2 days starvation); T2 (4 days starvation) and T3 (8 days starvation). At the end of the starvation periods, blood samples were collected from the caudal vein and were immediately transported to the laboratory for analyses. Hematocrit value in the control group was significantly lower (P<0.05) than the fish starved for 2 days. MCHC value in the control group was significantly higher (P< 0.05) than the fish starved for 2 days. Hemoglobin concentration, RBC and WBC counts, MCV and MCH did not show any significant difference between the treatments and the control group (P>0.05). WBC count decreased with longer starvation periods, though not significant (P>0.05). It could be concluded that hematological factors of juvenile Siberian sturgeon were not significantly affected by short-term starvation. But analysis of these factors alone might not give a clear picture of the physiological condition of fish and hence the use of other blood physiological factors is suggested in future studies.