JOURNAL OF MARINE SCIENCES AND TECHNOLOGY
Year:2003 | Volume:2 | Issue:4|Papers Count:11

In order to survey PAHs in sediments of Siri Island (Persian Gulf) Sediment samples were collected from 8 stations in November 2002, using Van Veen Grab sampler. Samples were transferred to the laboratory (4°c), completely freez- dried, then extracted by soxholet and ultimately concentrated by nitrogen gas. The concentrated samples were passed through the column of chromatography, sliced and washed by hexane and methane dichloride. Finally, the qualitative and quantitative analyses were carried out respectively by GC/MS and HPLC.In qualitative analysis, the maximum concentration observed in four stations was dimethylnaphtalene and the minimum concentration was hydroxy biphenil. In quantitative analysis, 0.01 µg/kg benzo-alpha-pyrene was the minimum of PAHs and 1.1 µg/kg benzo (a) anthracene was the maximum of PAHs.

The acute toxicity of cadmium sulfate to Pontogammarus maeoticus at two temperatures of 12±1°C and 19±1°C, were determined and their LC50 for 96h were compared. Toxicity tests were carried out under static conditions and consisted of 3 stages (Survival test, lethal range determination and main toxicity test). After calculating the mortality during 96h in the main toxicity test, the CdSo4 LC50 for two temperatures were determined by Pharmacologic Calculation System software. LC5096h of CdS04 at 12±1°C and 19±1°C was calculated 52.90 and 37.38 µg/L, respectively. The results indicated that Pontogammarus maeoticus was more resistant to CdSo4 at the lower temperature.

Changes in some quality indices as moisture (M), total lipid (TL), peroxide value (PV), thiobarbitoric acid (TBA), free fatty acid (FFA), heme iron (HI) and sensory evaluation such as (texture, general appearance, eye, color and odor of gills) in silver carp, Hypophthalmichthys molitrix, were determined during 1, 4, 7, 10, 13 and 20 days ice storage periods. Statistical analysis showed significant decrease in lipid quality of all samples with regard to oxidative and hydrolytic deterioration (P<0.05). Also, sensory evaluation through indices of eye, texture, general appearance, gill odor and gill appearance were recorded excellent to good till 4th and good to acceptable until 10th days.

Regarding the role of sex-reversed fish in production of all-female rainbow trout, sperm traits of neomale rainbow trout (treatment 1) were compared with those of normal (XY-male) males. Sperm sample were obtained directly by stripping from normal males (control) or by surgery of testis (treatment 2). Spermatocrit, sperm motility, duration of sperm motility in water and diluent solution, fertilization rate and the percentage of produced normal larvae, were compared. Final results revealed that all assessed traits were identical, expect spermatocrit and sperm motility. There was no difference between spermatocrits from neomales (84%) and those from normal males of treatment 2 (78%), but the spermatocrit from these two groups were higher than spermatocrits from normal males (35.33%) in control. The number of motile spermatozoa from normal males (control) was higher than those from neomales, which was, in turn higher than those of normal males of treatment 2 (P<0.01). Gonadosomatic Index (GSI) assessment results showed that GSI was higher in neomales (P<0.05). The results also suggested that the use of diluent solution led to longer period of sperm motility duration in neomales (P<0.05).

Abundance and diversity of fish larvae in the Farakeh Creek-Estuary area of the Bushehr's northern coastal waters was investigated from Sept. 2000 to Sept. 2001. Sampling was performed once per month in three designated stations of Dobeh Creek, Ramleh Creek and Farakeh Creek-Estuary, covering a total area of 10 km2. Samples were collected by pulling Bongo net of 500µ mesh size obliquely from the sea bed to the surface. Parameters such as salinity, temperature, pH and transparency were also recorded.Totally, 2106 larvae at various stages of preflexion, postflexion and early juveniles belonging to 15 families were collected. Total larval abundance in the covered area was estimated to be 40551.2535 in number. The most abundant larvae were found to belong to Clupeidae, Gobiidae and Sillaginidae, respectively, constituting 93.82% of the total larval abundance. Majority of the identified larval samples were found to be typical neritic and tidal zone faunas inhabiting soft and muddy sea bed. The abundance peak was found to occur in Mar-Apr, and decreased in Jun-Jul as temperature increased. The highest abundance was recorded in Dobeh and Ramleh Creeks, respectively. No significant differences (p<0.05) in species diversity, richness and evenness among the larvae from the covered stations were found, indicating even habitats of the covered area.

To determine the staying period of millions of the Persian sturgeon, Acipenser persicus, fingerlings released annually into the Tajan River, in the restocking programs, and also to estimate the number of fingerlings that make its way to the sea, this work was conducted. For this purpose, 40000 tagged fingerlings of various mean weights were released in four phases at two predetermined releasing stations. The tagged samples were later caught at two sites along the river and its mouth (estuary) using 10mm mesh size gill net.The survey indicated that fingerlings passed through the river mouth into the sea within 12-72hours after their release. The peak migration time was 0-3 a.m. The results also revealed the staying period of the fingerlings released at distances of 500 and 1500 meters from the estuary was directly related to such factors as releasing time, fingerling weight and the distance from the estuary. The fingerlings with lower mean weight were found to have longer stay in the river; in other words, bigger the fingerlings, the quicker they reached the sea. About 50-80% of the fingerlings made their ways to the sea in this survey.

Genetic variation of stellate sturgeon, Acipenser stellatus, from the North (Volga river) and South (Gorgan river) Caspian Sea was investigated using NADH 5/6 gene and PCR-RFLP analysis. In this study, a total of 60 samples of stellate sturgeon from the North and 14 samples from the Southern Caspian sea were collected. MtDNA ND 5/6 gene was amplified by polymerase chain reaction (PCR). PCR-product digested using 31 end nucleases restriction enzyme. Five of the 31 enzymes showed polymorphism (RsaI, HinfI, HpaII, HaeII/, MboI). Totally 18 composite heliotypes among 74 samples were detected. Haplotypes AAAAA, BAAAA, ABABA from the Vo]ga river showed 28.33%, 11.66% frequency, respectively, and from the Gorgan river heliotypes AAAAA, BAAAA showed 64.28% and 14.28% frequency, respectively.Average haplotype and nucleotide diversity within the populations in Volga river was 0.88±0.027 and 0.0122 and in Gorgan river was 0.5934±0.144 and 0.00398, respectively. Average nucleotide diversity and nucleotide divergence among populations of North and South Caspian Sea was 0.008644 and 0.000542, respectively.Monte-Carlo simulation using 1000 replication showed no significant difference between sampling site in the southern and northern Caspian Sea (X2=0.926±0.0083).

The microsomal cytochrome P450 dependent mixed function oxidase systemes is responsible to catalyze the first step of chemical Biotransformation. In this research the inducing effects of 3- Methyl Cholantheren were studied in Acipenser persicus microsomal mixed function oxidase. Fish were received 3- MethylCholantheren at doses about 20 and 40 mg/kg body weight/day i.p.for 3days respectively. In treatment fish did not observe any significant changes in anilin 4 –hydroxylase and NADPH - cytochrome C reductase, but 3 - Methylcholantheren treatment caused a 20 - 25 fold increase in 7 - Ethoxyresorufin- O-deethylase (EROD) activity of fish liver microsome.Acipenser persicus liver microsomal EROD activity was investigated with respect to substrate concentation, amount of enzyme, incubation period and temperature.  SOS -PAGE of microsomal protein pattern was showed that there is a protein with molecular mass of 58±1 KDa. So induction effect of 3 -Methylcholantheren could be induced isoenzyme P4501A. and is increased the isoenzyme biosynthysis.