مجله علوم شیلاتی ایران (انگلیسی)
سال:1379 | دوره:2 | شماره:1 |تعداد مقالات:21

The Kor River (Fars province) was divided into three parts and water and fish specimens were collected monthly and the concentrations of four heavy metals were determined using the Induction Coupled Plasma Method. As middle sampling zone was the main entrance and discharges of industries into the River, the concentrations of heavy metals in tissue of fish from this zone were significantly higher (p<0.05) than those from the other two sampling zones, whereas no significant differences (p>0.05) were detected between the two sexes and species. Maximum concentrations of lead, mercury and cadmium in fish tissues were higher than the permissible levels for human consumption. Significant changes in the concentrations of steroid hormones were also noticed between the middle and two other sampling zones. Also in middle sampling zone, pathological changes in blood cells, liver, and kidneys of fishes were significantly higher. So heavy metals exposure can effectively decrease estrogenic and androgenic secretion in fish. The results confirmed exposure of fishes to heavy metals not only disrupts reproductive hormones’ secretion, but also induces some pathological changes.

Twenty-four Black-lip Oysters (Pinctada margaritifera) were collected in summer (July) 2004 from six coastal locations in Kish Island (Persian Gulf) and were analyzed at the analytical laboratory of Great Lakes Institute for Environmental Research at the University of Windsor according to the chemical analysis procedures which has been accredited by the Canadian Association for Environmental Analysis Laboratories (CAEAL). In order to obtain information on bioavailability of sixteen EPA priority polycyclic aromatic hydrocarbons (PAHs), concentration of 2 to 6-ring PAHs was determined for all samples with application of a gas chromatograph with a mass selective detector. Oysters from Big Coral site exhibited a wide range of total PAH concentration (1.07 to 77.66 ng/g wet weight). The lowest value (oysters from Foreigner’s Pelage) and highest values were 0.7 and 36.33 ng/g wet weight respectively. Comparison of the PAH concentrations in oysters with sediments collected from the same locations showed that the overall bioaccumulation has been performed through the movement of water-soluble lower molecular weight (LMW) PAHs to the oysters in the studied area.

Rajaee port in Bandar Abbas is one of the important-oil transport hubs in Persian Gulf and any oil spill incidents can result in pollution, which impact on human habitats and the marine environment. Oil spill trajectory modeling is a tool which applied to increase the knowledge about oil spill fate. The GNOME model is a physical model which indicates the oil spill movements on sea water and potential risk areas. The model inputs include GIS data, time of spill release, release duration, spill chemistry and physical characteristics of wind and current data. Two scenarios for 10 and 200 bbl of diesel and gasoline spills are run on the model. Both the general Persian Gulf circulation which is from the south west and the local wind direction cause to move the oil spills toward the Bandar Abbas coast and Qeshm Island that pollutant these areas. Both regions are very valuable economic and environmental zones. They have known as risk places due to the oil spills that release from Rajaee Port in this study. The model results can assist organizations in preparing their emergency management systems for responses in the potential risk areas.

The ultimate goal of an agriculture research system is on-time, correct and clear response to the problems and expectations of agriculture household and stakeholders. In this respect, though, due to variation and frequency of the problems and expectations and as well as many limitations such as financial deficit, short time and shortage in work force and equipments etc, the system cannot be thoroughly responsive. Therefore, the necessity for optimizing the system to response through prioritizing the research projects has been a major challenge before the responsible managers and authorities. In this paper, the Analytical Hierarchical Process (AHP) has been introduced as a well known Multi Attribute Decision Methods (MADM) that combines qualitative and quantitative criteria for prioritizing the research projects of the Iranian Fisheries Research Organization. For implementation of the mentioned principles and methods of prioritizing the research projects have been studied and then by determining the final decision making criteria, the priority of the projects in the Institute have been determined by drawing decision hierarchy tree. Required data was gathered through pair wise comparison questionnaires filled by the experts and researchers. In the next step, Expert Choice software used to analyze and determine the priorities. Based on results criteria of research possibility, scientific development, economic development, and stability development with respective weight. 37, .263, .187, and .173 are the most important criteria for the institute in the south area of Caspian Sea. Finally, according to the produced results, the priorities of the six studied research programs determined.

The chemical composition variations of the Indian mackerel (Rastrelliger kanagurta) from Karachi coast were investigated seasonally over the period of one year (2004-2005). Moisture, crude protein, fat and ash contents varied from 70.11-74.41%, 16.02- 20.09%, 3.0-12%, and 0.89-1.35% respectively. The seasonal data indicated that the main fatty acids of the total lipid were C16: 0, C16: 1, C18: 0, C18: 1, C20: 5 and C22: 6. Total contents of saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) percentages varied from 31.6-46.85%, 20.5-27.9%, and 26.8-40.85% respectively. Eicosapentaenoic acid (EPA, C20: 5n-3) and docosahexaenoic acid (DHA, C22: 6n-3) of omega 3 series which have specific importance in nutritional values concept, were the major fatty acids. The lowest EPA and DHA were found to be in July and highest in November to March.

The effect of gamma radiation (1, 3 and 5 kGy) on microbial quality of farmed rainbow trout (Oncorhynchus mykiss) fillets which were stored under frozen conditions (-20oC) was studied by measuring microbiological changes in 5 months. Gamma irradiation and increasing of frozen storage time had significant effects (P<0.05) on the reduction of microorganism's population. The total count showed that all samples maintained acceptable microbiological quality until the end of the fifth month of frozen storage. The lowest microbial load at the end of the fifth month of frozen storage was related to irradiated samples at 3 kGy (2 Log CFU/g). Yeasts and molds were below the detection levels in both irradiated samples at 1 and 5 kGy until the end of the third month and in irradiated samples at 3 kGy throughout the frozen storage. The population of yeasts and molds increased in irradiated samples at 1 and 5 kGy in the fourth and fifth month of frozen storage. Growth of coliform bacteria and Salmonella wasn' t observed in control and irradiated samples due to good hygienic quality of fish breeding, fishing, handling, filleting and packaging and also effect of freezing on elimination and inactivation of mesophilic microorganisms.

Chalcalburnus mossulensis from the cyprinidae family is one of the indigenous fish in Gheshlagh Lake of Kordestan, Iran. Ligula intestinalis is one of the infective parasites among various species of fish and causes gonads atrophy. In this study, after detection of species and age of samples, the effects of this parasite on gonads tissues and sexual maturation of Chalcalburnus mossulensis were investigated. By seasonal sampling 144 samples were collected. After investigatiing gonad tissue samples, it was clear that, there is a significant difference between the means of male and female gonads maturation rate in infected and non infected samples (p<0.05). Infection by Ligula intestinalis can be the reason for lack of gonads maturation. In addition, the abnormal degenerative changes like, absorption follicle, hemorrhage and infiltration of inflammation cells in ovary tissues of infected fish were seen. In testicle tissue, dispersed hemorrhage, atrophy and MMC (melano-macrophage center) were seen as pathological signs. So the spread of this parasite in different water sources is important as the point the maintenance of native species and cultivated fish.

In this study a parasitological investigation on 238 samples of Neogobius species from the south-east of Caspian Sea was carried out. The samples including Neogobius melanostomus (35), N. fluviatilis pallasi (103), N. kessleri gorlap (70) and N. bathybius (30) were seasonally seined by beach net during one year (summer 2006-spring 2007), fixed in 10 % buffer formalinand transferred to the laboratory. From 231 of examined fishes 235 specimens were infected (97/6 %). The collected parasites were as follows: Hysterothylacium aduncum, Raphidascaris acus, Cucullanus sphaerocephalus, Dichelyne minutus, Raphidascaroides sp., Cystidicola sp,. Gyrodactylus sp., and Corynosoma strumosum. Hereby, N.melanostomus is introduced as a new host for Raphidascaroides sp., C. sphaerocephalus and Cystidicola sp.. N. fluviatilis pallasi and N. kessleri gorlap for C. sphaerocephalus, Cystidicola sp. and H.adunacum. N. bathybius for C. sphaerocephalus, Cystidicola sp., H. aduncum, E.excisus, R. acus and C. strumosum. Cystidicola sp. and H. adunacum were reported for the first time from Iran. Among the investigated fishes N. fluviatilis pallasi possessed the highest and N. bathybius the lowest variety in infection with various species of parasites. The results of this study indicated that there are significant relations between total length (T.L.) and weight in N. fluviatilis pallasi with the number of C. sphaerocephalus, D. minutus and E. excises. Also there are significant relations between total length and weight in N. melanostomus and between weights in N. kessleri gorlap with the number of C. sphaerocephalus.

Over the past few years, the syndrome of streptococcosis has been associated with outbreaks in rainbow trout (Oncorhynchus mykiss, Walbaum) and caused significant economic losses in the aquaculture industry in Iran. The main purpose of this work was molecular identification of some causative agents of streptococcosis in rainbow trout. A total of 520 samples were collected from the head kidney of diseased fish (weight, 50_200g) in 72 farms of 8 provinces in Iran, during 2008 to 2009. Bacterial isolates representing morphology and biochemical profiles of Streptococcus spp. were further confirmed by polymerase chain reaction (PCR). DNA extraction was carried out from a single colony by using the extraction promega kit following the conditions described by the supplier. The PCR assay was developed based on the 16S rRNA and glucose kinase genes of Streptococcus spp. for the rapid and specific detection and identification of this pathogen from different sources. Approximately 40% of specimens were infected to Streptococcus spp. Consequently, five pathogenic species have been identified, including S. iniae in Fars province, S. faecium in Mazandaran province, S. agalactiae in Gilan and Mazandaran provinces, S. dysgalatiae in Lorestan, Kohgiluyeh and Boyerahmad, Gilan and Kermanshah provinces and S. uberis, which was common in all provinces (except Mazandaran and Lorestan). The dominant species (based on important species index) were S. uberis, S. dysgalactiae and S. agalactiae, respectively.

Sampling was done using 90 post larvae which were produced by reproduction of some broodstocks of Fenneropenaeus indicus in one day and reared in the same situation for 4 months. Samples were divided into 3 groups: high, medium and low growth (based on weight and length). Genomic DNA was extracted from muscle tissue using the phenol-chloroform method. The polymerase chain reaction (PCR) was carried out using 21 RAPD loci and PCR products were separated on 3% Agarose gel. From 21 loci studied, 12 produced polymorphic bands. The most polymorphic produced bands using OPAQ 9 and the least by OPAQ 7. Search for specific markers in F. indicus one specific band was observed in the low growth group using OPAQ4. The highest genetic distance (0.457) was between the low growth group and the medium and the lowest (0.091) between high growth and medium groups, therefore the highest genetic identity (0.912) was between high growth and medium groups and the lowest (0.633) between low growth group and the medium. Neighbor-joining resulted in two groups, the first including high and medium growth groups and the second low growth group. It appears that low growth group depended on separated population. Considering the mean weight of F1 (mean weight of 90 specimens) (16.25±1.5 g), parental generation mean weight of 15±1.2 and mean weight of parent 31.6 g, response to selection (R) and heritability for growth in this species were estimated to be 1.2±0.2 and 0.07±0.01 respectively.

For this study one species of Shyrnidae family caught along Persian Gulf in Bandarabbas city. Sphyrna lewini were transferred to the laboratory on spring 2007. The antimutagenic activity of the Methanolic and Chloroforamic extracts of muscle, liver and cartilage of Sphyrna lewini with the Ames test was investigated. The use of antimutagens and anticarcinogens in everyday life is the most effective procedure to prevent human cancer and genetic diseases. Since angiogenenesis is a key factor in tumor growth, inhibiting this process is one way to treat cancer. In this study the antimutagenic effect of the Chloroformic and Methanolic extracts of muscle, liver and cartilage on the damage induced by two mutagens was studied. The results driven from this study were inhibitory effect of two extracts. The highest antimutagenic effect was determined in the Potassium Permanganate and Sodium Azide as a mutagen was Methanolic extracts of cartilage. There is a general correlation between mutagenesis and the initiation stage of carcinogenesis. Mutagens appear to initiate the process by inducing the primary DNA lesion. These are called initiators and the damage they cause is generally irreversible.

In this study the forward and reverse primers were designated to amplify the segments (~250 bps and ~650 bps) of the gene coding domains 1 and 4 of aerolysin of Aeromonas hydrophila. These two domains are involved in pathogenesis of the aerolysin gene. Sequences for two restriction enzymes, Pst I and Hind III, were included in the forward and reverse primers respectively. These restriction enzyme sites were used because they are not present within the genes of interest but are available in the multiple cloning sites of plasmid pNZ8048. Amplified PCR products were analyzed with 1% agarose gel electrophoresis and results showed that amplifications were very specific. In comparison with the DNA marker, the sizes of the amplified PCR products were determined to be approximately ~250 bps and ~650 bps respectively. PCR products were then purified by the DNA purification kit, digested with REs and ligated with linearised pNZ8048 plasmid using T4 DNA ligase. Transformation of Lactococcus lactis NZ9000 cells was performed by the electroporation method. Verification for cloning of virulent genes was performed by REs digestion and also DNA sequencing. Since several antigens (bacterial and viral) and cytokines have been efficiently produced in L. lactis, constructing and expression and utilization of recombinant L. lactis harboring the aerolysin domains (virulent) genes from A. hydrophila may induce production of antibodies in fish against this pathogen.

The normal and lateral line cycloid scales of a cyprinid fish Rutilus frisii kutum Kamenskii, 1901 have been subjected to scanning electron microscopy technique to study their detailed structure. The scales have the general morphological characteristics of the cycloid scales. In the normal scale located below the dorsal fin, the focus lies on the anterior region with few mucous pores. There is a clear-cut demonstration between the anterior and posterior region. In the posterior part, the scale has several rows of pigmented granules (tubercles) with different shapes of round to oval, semi-oval and even oblong structure. On the dorsal side, some circuli bear teeth-like structures called lepidonts can be seen which help the scale in firm attachment to the skin. The circuli may also have calcium projections. The lateral line scale has a canal which characteristically lies along the anterior-posterior axis with anterior and posterior openings. The anterior opening is wider than the posterior one and is hidden by an evelike extension cantilevered over it. Based on the obtained results it could be concluded that the shape and size of lepidonts on the circuli crest, the position, shape and size of tubercles and the presence of both anterior and posterior radii may provide reliable taxonomic tools. Changes in the circuli pattern, breakage of the circuli, loss of lepidonts and tubercles may be used to access the habitat condition of this carp especially habitat pollution.

Effect of nanosilver particles was studied on the hatchability of rainbow trout (Oncorhynchus mykiss) egg and survival of the produced larvae at about 12oC. In the first experiment the water-based nanosilver particles was used at concentrations of 0.5, 1, 2 and 4 mgL-1 for 30 minutes per day starting 24 hour post egg incubation until the hatching time. The mean percentage of hatchability reached in 27.6±0.2, 38.2±0.1, 41.6±0.4 and 48.6±1.5 in troughs treated with 0.5, 1, 2 and 4 mgL-1 nanocid, respectively compared with 64.7±0.2 % for trough treated with malachite green at 2 mgL-1 as positive control (P<0.05) and 5.1±0.2 % for trough without treatment (untreated group) (P<0.0.5). In the second experiment the effect of the nanosilver particles was evaluated in the form of nanosilver dressing i.e. coating nanocid on the surface of the incubator troughs. The mean percentage of hatchability was 69.4±0.1% compared with 52.5%±0.1 recorded for normal control (trough without nanosilver dressing) (P<0.05). When growing the produced larvae in the same troughs until one g in body weight, there was an insignificant increase in the weight of larvae kept in nanosilver trough (mean weight 1.12±0.09 g) compared to control group (mean weight 1.03±0.02g) (P>0.05). These data suggest a possible application of nanosilver particles in aquaculture sector particularly using incubator troughs of trout containing nanosilver materials.

Crustaceans are ecologically important, because of their effective role in food web and community structure of ecosystems. Taxonomic identity of fresh water crabs has been studied in Iran representing Potamidae family as dominant fluvial crabs (Khatami, 2001). Khatami (2001) also recorded an unknown oligochaete in the mantle cavity of fresh water crab “Potamon persicum”. The present study further separated and identified an oligochaete from Potamon persicum in Jajrood River, east of Tehran, Iran.

According to the records of FAO (Food and Agriculture Organization), Shabut, also known as Barbus grypus, is one of the most signifcant fish species listed in the fresh waters of Iraq and in the rivers along South and Southwest Iran, the Karoon river, and also in The Euphrates River and Tigris Rivers in Turkey (Selki et al., 2005; Zivotofskya & Amar, 2006; Dorostghoal et al., 2009). This fish with dark anal and tail fins and other light colored fins (Selki et al., 2005) is one of the leading fish species from the Ataturk Dam Lake with great importance in economy (Olgunoglu et al., 2009).