نشریه علوم و فنون شیلات
سال دوم شماره 2 (پیاپی 3، تابستان 1392)

The effect of nonylphenol on vitellogenin and zona pellucida 3.1 expressions in the liver, spleen, gill and muscle tissues of the juvenile Persian sturgeon were investigated. The fish were initially injected per kilogram of their body weights with 100mg nonylphenol, 5mg 17 beta estradiol, and 2ml peanut oil carrier agent (respectively, for the main treatment, positive and negative controls), and had the extracted RNA of their tissues converted into cDNA. Afterwards, RT-PCR reaction for each tissue sample was done separately. Results showed vitellogenin gene was expressed only in the liver, but zona pellucid 3.1 gene was expressed in the liver as well as the spleen of the fish exposed to nonylphenol and 17 beta estradiol. No vitellogenin gene in the spleen, gill and muscle was expressed; no gene for zona pellucida 3.1 was either observed in the gill and muscle. The expression rate of vitellogenin gene was 9.95±2.48 for the treatment with 17 beta estradiol and 2.85 ± 0.35 with nonylphenol; the expression rate of zona pellucida 3.1 was 9/98 ± 2/51 for exposed treatment with 17 beta estradiol and 3.37±0.35 for the treatment with nonylphenol. In conclusion, considering the meaningful effect of nonylphenol on vitellogenin and zona pellucid 3.1 expression in liver and spleen, it could be used for detection of xenoestrogen biomarker in the Persian sturgeon.

The effect of sublethal concentrations of cadmium on some haematological parameters of juvenile sterlet, Acipenser ruthenus. For this purpose, 60 fish (41.69 ± 0.95 g and 23.98 ± 0.14 cm) were randomly divided into four experimental groups and exposed to 0 (control), 16, 32 and 64 μg/L Cd concentration, each in 3 replicates for 21 days. The hematological parameters, including red and white blood counts, differential white blood count, hematocrit (Hct), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) and white to red cells ratio were determined using standard methods. The highest level of Hct (30.57 ± 1.91%) was observed in fish exposed to 64 µg/L (p0.05). The results indicated at least some deleterious effects of sublethal concentration of Cd on some hematological parameters of sterlet, which maybe reflecting the stress response as well as deleterious effects on haemopoietic tissues.The study of long term effects of Cd exposure of starlet is suggested.

Feeding of Daphnia magna with two unicellular green algae, Ankistrodesmus falcatus and Scenedesmus obliquus, was investigated. The experiment was conducted in three replications and under similar condition (Z-8 medium and 14L: 10D). The results indicated that the filtration rate by D. magna decreased with increasing algal concentration, but no significant difference between the two treatments was evident (p>0.05). Increase in algal concentration resulted into significant increase in the ingestion and feeding rates of D. magna (p0.05). Based on the presented results, D. magna performed better when fed with S. obliquus.

The effects of lidocaine on water quality and some hematological parameters in simulated transportation of the fingerling common carp, was investigated. Dissolved oxygen and ammonia of the control group and 0.01, 0.03 and 0.05 ml/lit lidocaine treated groups were tested at 0 h, 1, 2 h, 3 h, 4 h and 5 h simulated transportation. For the hematological assessment, blood samples were collected from the caudal peduncle of fish in all of the treatments at the beginning and termination of the experiment. The results showed decreased oxygen consumption and ammonia excretion by the fish treated with lidocaine during the experiment. No significant differences in the hematological parameters were found in the levels of RBC, Hb, HCT, MCV, MCH, MCHC and WBC in all the groups (p

Factors affecting the spatial variations of water quality of the Mazandaran coastal ecosystem was determined in summer 2012. For this purpose, water quality parameters (nutrients, temperature, conductivity, salinity, dissolved oxygen, pH, chlorophyll α and turbidity) were evaluated along 4 transects (Amirabad, Babolsar, Noshahr and Ramsar) in the depths of 5, 10, 20 and 50m, using multivariate analysis methods. Based on the cluster analysis of data, the sampling sites could be classified into 5 distinct groups, including 35-50m water layer of station 50m in all transects, 0-5m layer in station 5m in all transects, Ramsar transect and the majority of surface and bottom layers of 3 transects including Noshahr, Babolsar and Amirabad. Based on discriminant analysis, 86.40% of the sampling sites were correctly classified. Factor analysis explained 87.53% of the total variance, the five principal components of which (viz. temperature, turbidity, nitrate, silica and ammonium) were considered as the most effective parameters on the spatial variation of water quality. This study suggests that the number of sampling locations can be reduced to two transects. Thermocline, transport of nutrients (specially phosphorus and ammonium) from rivers, sea floor, cage culture and the ctenophore, M. leidyi, were the most effective sources on spatial variations of water quality. Moreover, the multivariate statistical methods were found to be useful tools to recognize the spatial variations pattern along the Mazandaran coasts in summer.

The acute toxicity and histopathology of Schizothorax zarudnyi (2±0.2 g body weight)exposed to diazinon was assessed statically in 22±2°C, following the OECD Guideline. The 96h LC50 value of diazinon for the fish was 14.70 mg/l, therefore making its MAC value 1.47 mg/l in natural waters. According to the table of insecticides sorting, the toxicity of diazinon was low for S. zarudnyi. Some clinical symptoms and abnormal reactions such as lordosis and neural paralytic syndrome, losing the balance and swimming in a half circle, expressive pigmentation mainly on the dorsal part and block of respiration movements in the fish exposed to this pesticide were observed. Histopathological evidence from the tissues of liver, kidney, gill, and gut revealed vascular tissue of the liver, sinusoids, hepatocytes vacuole degeneration, shrinkage and degeneration of some urinary cells, dilatation of Bowman's space, pycnotic nucleus of some kidney cells and increase in the number of interstitial kidney cells. Complications, such as hyperemia, telangiectasia, edema, shrinkage, clubbing and adhesion to the secondary gill filaments were also observed.

Aquaculture production is often accompanied by some stressors which undesirable effects on growth and physiological function. Music is one of the cases that could eliminate or reduce the effects of stressors. The purpose of this study was to determine the effect of Iranian traditional music on growth, reproduction and behaviour of zebra cichlid (Pseudotropheus zebra). Fish with an average weight 5.5  0.18 g were put under both music and silence treatment with the number of 2 fish/aquarium with 3 replicates for 4 weeks. Fish under music treatment were put twice a day and every 30 minutes under the Iranian traditional music. At the end of this period, suitable conditions for fish were created to spawning. The results showed no significant differences in growth parameters, but 50 percent of fish during the 2-week were spawned in music treatment. However, only 16.6 percent of fish under silent treatment were spawned. Of eggs and spawn time, significant differences were observed between two groups. When is music being played, the fish were found mainly along approach the speakers, while the distribution of fish treated silence was uniform. The results of present study showed that use of music can affect physiological function of fish, which have more tranquility and less stress on fish.