فصلنامه اقیانوس شناسی
پیاپی 16 (زمستان 1392)

As there are gaps in applying an ecosystem approach to fisheries assessment and multispecific ecosystem based-management in the Persian Gulf، feeding ecology and trophic relationships of some of the important fishspecies (Sillago sihama، Pomadasys kaakan، Parastromateus niger، Rastrelliger kanagurta، Psettodes erumei، Drepane punctata، Lutjanus malabaricus، Lethrinus nebulosus، Acanthopagrus latus. and Otolithes ruber) were studied in the coastal waters of Hormozgan Province (Persian Gulf). The stomach contents of 2480 trawling fish were studied between November 2009 and December 2011 by random sampling method. A multispecific ecosystem-based approach on trophic relationships and their possible variations was built using the ECOPATH software system (ver. 6. 3). The results of this study indicated that the trophic levels of the species varied between 2 to 4. 30، in which Liza klunzingeri and Lethrinus nebulosus showed lowest and highest values، respectively. In addition، any changes in the prey biomass could affect the biodiversity and، in the long run، the biomass of the main groups of the food chain in the Persian Gulf.

In this study، for the investigation of testicular structure and pattern of reproductive cycle in the male Caspian kutum، the sampling was achieved monthly from Jefrood coasts (Anzali، Guilan province، 37º 27´ N; 49º 33´ E) from October 2011 to late April 2012. After macroscopic observations and photographing position of sexual organ، the male gonad sections were removed and fixed in Bouin’s solution. After applying of various steps of histological method، 5 micron sections were prepared، then stained with hematoxylin– eosin and finally were examined by optical microscope equipped with a camera. The results showed that the developmental stages of kutum testis were divided into four stages. In Stage I (early maturing)، the testes were thin and contained the spermatogonia and the primary spermatocyt. In stage II (late maturing)، the primary and secondary spermatocytes were the most visible cells. In matured stage (stage III)، all developmental stages of spermatogenesis were observed. In stage IV (ripe)، the largest volume of theabdominal cavity occupied with lobules and they were full of spermatid and DNA carrier spermatozoa. In general، the pattern of testicular growth was lobular system in the Caspian kutum and the process of sperm formation was done in the defined period from October to April.

Bisphenol A (BPA) is an endocrine disruptor (ED) that is abundant in marine environments because of its extensive use in manufacturing polycarbonate plastics and epoxy resins. In the present study، effects of BPA on thyroid hormones and blood cells were investigated to detect endocrine and cytogenetic damages in yellowfin seabream inhabited in selected sites in Musa Creek. The results indicated significant reduction in plasma triiodothyronine and high level of plasma thyroxine in treated fishes in comparison to the control groups and in dose dependent manner. In addition، using Micronucleus test (MN) showed induction of micronucleus in exposed fish samples. Therefore، the results of this project indicated the potential effects of (BPA) causing endocrine disruption and cytogenetic damages. Hence، monitoring thyroid hormones and undertaking MN test could be useful to evaluate the potential damage occurred in the fish samples either in controlled or natural marine environments.

In this study، single or combined effect of fructo- and mannan oligosaccharide supplements on growth performance، survival، body composition and resistance rate in juvenile Roach (Rutilus rutilus caspicus) were investigated for 10 weeks. Commercial roach diet (containing 38. 45 percent protein and 9. 87 percent lipid) were supplemented with 0 (control)، 5 g kg-1 Fos، 5 g kg-1 MOS and 2. 5 g kg-1 Fos + 2. 5 g kg-1 MOS. Juvenile roach، initially weighing an average of 1. 45 ± 0. 11 g، were distributed at a stocking density of 50 fish per tank and fed up a day. There were no significant differences in growth and feeding parameters between fish fed control and MOS and FOS supplementation diets (P>0. 05). The highest and the lowest growth performance were observed in 5 g kg-1 FOS and combined treatment، respectively. There were no significant differences in survival rate among experimental groups (P>0. 05). There were significant difference in crude lipid carcass between control and 5 g kg-1 MOS group (P<0. 05)، while no significant difference was observed in protein carcass between treatment (P>0. 05). At the end of experiment، there were no significant difference in survival index to thermal (40°C)، salinity (14. 7 ppt)، and acidity (pH=2) stress. In the test of alkalinity stress، minimum of survival time was obtained in control group (P<0. 05). The result indicated that including the price index، 5 g kg-1 MOS could improve growth performance and survival in some of the stress tests juvenile roach.

This research was carried out to compare diversity and distribution of polychaetes in western and eastern Jask creeks protected areas in Jask Port (Gulf of Oman)، located in the East of Hormozgan province. Sampling of sediments was done seasonally from fall 2009 to summer 2010 by 0. 04m2 Van Veen Grab، in three stations including mouth، middle and end of each creek. A total of 72 sediment samples were taken from the stations. In this study، 20 species belonging to 16 families in the easten Jask area with a frequency of 9075 per m2 and 17 species belonging to 13 families in the western Jask area with a frequency of 4800 per m2 were identified. Polychaetes families were mainly consist of Nereididae، Owenidae، Capitellidae and Pilargidae. Ecological indices including Shannon - Wiener، Margalef and Simpson also were calculated. The average of Shannon index in different seasons and stations of eastern Jask (1. 02±0. 47) were higher than the western Jask (0. 898±0. 74). Correlation analysis between environmental factors and polychaetes showed that the abundance of polychaetes has a significant positive correlation with the temperature، oxygen، salinity and EC (P<0. 05). Results of ANOVA revealed no significant differences between indices in different seasons (P>0. 05). The results of Kruskal-Wallis test showed significant differences between the abundance of polychaetes in the eastern and western Jask (P<0. 05). In additon، the results of this test indicated a significant difference in the abundance of polychaetes، between summer and fall and also between summer and winter، in both of Eastern and Western Jask (P<0. 05).

This study was done to investigate the relationship between microstructure destruction and water holding capacity (Water holding capacity، WHC) of Hammor (Epinephelus coioides) fillets، after caught and during refrigerated storage (4°C). 30 fresh Hammor samples were provided from Hormozgan Pier Fishing in 2012 and manually filleted. The fillets were stored in a refrigerator for 14 days and pH، WHC، and muscle fibers indexes were evaluated on days 0، 4، 7، 10 and 14 of storage. WHC of fillets decreased during days of storage and the distance between muscle fibers increased (P<0. 05). Liquid loss and water loss increased from % 13. 7 and 12. 7 at the initial storage to % 23. 9 and 21. 3 at the end day of storage، respectively. Changes in the distance between fibers were in the range of % 4. 70- 59. 25. The results showed that the increase of liquid leakage and decrease of WHC was probably due to destruction of muscle fibers at the end days of storage.

The Current study was conducted to evaluate the effects of dietary supplementation of lysine and/or methionine on growth performance and survival rates in Persian sturgeon (Acipenser persicus) fingerlings reared under culture conditions in Iran for fifty days from 15 June 2011 to 6 August 2011. Experimental fish were fed five practical diets supplemented with 0 (as a control diet)، 1 and 3 % of lysine and methionine in a 2×2 factorial design experiment. The experimental groups were fed in triplicate. A total of 360 A. persicus fingerlings with an average weight of 1. 8 ± 0. 3 g (mean±SD) and an average total length of 7. 1 ± 2 (mean±SD) cm were randomly allocated to eighteen 50-L aerated tanks (20 fish in each tank) with flow rate of about 0. 2 l/min. The results indicated that there were significant differences in growth performance among treatment. Maximum weight gain (10. 1± 2. 5 g)، body weight increase (461. 9±138. 6 %) and special growth rate (10. 7± 0. 7%) occurred at 3% dietary methionine and lysine. But the survival rates were not significantly affected by dietary lysine and methionine levels.

Hormone disruptors are chemicals that interact with endocrine system in human and especially water aquatic animals. In this study، the effects of nonylphenolethoxylates on plasma testosterone have been investigated in Zebra Cichlid (Cichlasoma nigrofasciatum). Fishes were exposed to three concentrations of nonylphenolethoxylates، 10، 50 and 100 μg / l compare to control (0 μg / l) and blank (Ethanol control) in three different size classes (average weight 3±0. 1g.، 4±0. 3g.، 5±0. 1g.) with 3 replicates. Zebra fish (n= 840) were examined during 60 days in glass aquariums. Blood testosterone levels were analyzed by radioimmunoassay technique. The results showed that all 10، 50 and 100 μg / l nonylphenolethoxylates concentrations have affected the blood plasma testosterone levels. Also، there were significant differences between testosterone concentration in different weight groups (P<0. 01). Nonylphenolethoxylates can disrupt plasma testosterone levels with more than10 μg / l concentrationvia hypothalamus-pituitary axis.

Sponges are one of the most important resources in marine natural productions. Therefore، it is essential to study their reproductive biology for protection and management of these species in aquatic ecosystemes. Despite broad biological knowledge، the role of reproduction in the structuring and maintenance of sponge population is limited. For this purpose، we studied reproductive biology of sponge (Dysidea fragilis) over a year. Samples were collected by diving in artificial reefs (12M) in Bahrakan، located in Northwest of the Persian Gulf. The samples were fixed in methanol، rinsing in 70% ethanol and run through an alcohols and xylene sequence. Paraffin blocks were made and serial 5 μm microtome sections were stained with H&P. The sea water temperature appears to play a fundamental role in the sponge reproductive process. The results showed that the onset and progression of reproduction in Dysidea fragilis coincided with water temperature and photoperiod. Synchronized، spermatocyties and Oogenesis were present in the spongocell. Oogenesis and spermatocyties occurred from least autumn and the maximum sizes over the sampling period were 18. 24±8. 11 and 8. 47±5. 11 μm (mean±SE)، respectively. Maximum size in emberyo was 75. 302±0. 05. As sponges are now recognized as one of the richest sources of marine natural productions، understanding the reproductive biology of them is essential for the effective management and conservation of the organisms population.

This study investigated the sensitivity of seashores by Environment Sensitivity Index (ESI) of American National Oceanic Atmospheric Administration (NOAA) method. Moreover، physical sensitivity of Hormozgan shore line was determined based on NOAA models، Habitat Priority Planner (HPP) and Geographical Information System (GSI). The results of present study showed that 10 major layers and 24 minor layers related codes have been recognized in the 1040 Km of Hormozgan coast. In this respect، layer 10D with 319. 87 Km width has accounted for most of the coastal area with 28. 13 percent. Layer 3A with 110. 13 Km long contains 9. 7 percent of the eastern and central coasts after layer 10D. Layer 1A with 93. 87 Km expansion and 8. 26 percent rate have third place in sensitive layers abundance chart. The results showed that this area is very sensitive to the potential disasters and oil pollutions and needs optimum shoreline management.

Wake is hydrodynamic footprint of a vessel at sea. The Earth''s magnetic field makes these footprints visible using magnetic sensors. Geomagnetic anomalies induced by the motion of vessels may extend several kilometers and stay up long hours under certain conditions. Physical properties of this geomagnetic anomaly are studied in this paper. A mathematical model is derived to simulate the anomaly in shallow waters. It is shown that the peak of geomagnetic anomaly spectrum is located in the range of frequencies where the corresponding value of the ambient noise spectrum is less significant. In addition، it is shown that there is an optimum depth in which the geomagnetic anomaly has a maximum. Variation of the geomagnetic anomaly with vessel speed is studied and it is shown that higher speed vessels make stronger anomalies in geomagnetic field.

This article deals with the geographical scope of the UN Convention on the Law of the Sea (1982) and specifically the geographical scope of the legal regime governing marine scientific research there in. Accordingly، each marine area starting from the baseline would be studied separately in order to draw a clear-cut picture of the MSR regime status both for the coastal as well as the researching states within Internal Waters، Territorial Sea، Contagious Zone، EEZ and Continental Shelf، High seas and the Area. Among the said marine areas، EEZ and Continental Shelf seem to have attracted far more attentions of marine scientists due to their special characteristics namely appropriate depth، hence been given a more complicated legal regime for MSR activities. Eventually، the article at hand would analyze terms and conditions envisaged in the UNCLOS in order for researching state demanding access to coastal state marine areas for the MSR purposes to obtain consent of the latter.