نشریه پژوهش های علوم و فنون دریایی
سال یازدهم شماره 2 (تابستان 1395)

In this research the effect of baffle on hydraulic efficiency of settling basin was investigated by applying two-dimensional numerical model. In these experiments, a steady state for water flow is assumed and for simulating the flow disturbances and also for examining the turbulence sphere, the standard (k-ε) model is used. The present study assessed the baffle effects with regard to the submergence depth and its distance from inlet flow. In order to explore the depth of submergence two depths (25 & 50 percent of basin depth) and for its optimal location, two positions (14 & 36 percent of inlet installment) were defined. The results indicated that the depth of submergence and baffles location in the basin can have a determining influence on the efficiency and the operation of settling basin. These results also showed that when the baffle is used correctly, the inlet jet available in the basin is restrained effectively. However, by exploiting in a wrong direction it can have reverse effect and make the condition even worst. The results also showed that by using 25% basin depth submergence and a distance of 14 % of installation entrance, entrance flow jet was very well suppressed and the flow became calm and had a more uniform distribution.

In this study, the effect of oral green skin of walnuts on the coloration of Oscar fish (Astronotus ocellatus) was studied. Sixty albino Oscar fish with an average weight of 5/01 ± 0/18 g and 54/84 ± 2/23 mm average length were divided in into three test experiments and one control and each with three repetitions. Twelve aquariums in the dimensions of 50 × 40 × 33 cm were used. The control was fed with a diet containing no food additives. The fish in treatment number one were fed with food containing %0.1 walnut hulls, the second treatment contained %0.2 walnut hulls in the fish diet and the third treatment was fed with food containing % 0.3 walnut hulls. The breeding period lasted eight weeks (56 days). Every 20 days biometrics (Biometry) were performed which included gravimetric analysis using a digital scale with 0.01g precision and a ruler with an accuracy of 0.1 cm for length analysis. Average water temperature in the aquarium during the study period was 28/07 ± 1/09 ° C. An average of 5/38 ± 0/15 milligrams per liter of dissolved oxygen, average pH of 8/03 ± 0/33 and an average TDS of 33/27 ± 1/32 mg was measured. At the end of the period of investigation, results showed that in terms of growth, the control with an average weight of 17/06 ± 1/21 grams and weight gain of 22/15 ± 1/08 grams had significantly (P<0/05) the highest growth rate compared with the other treatments. The third treatment with an average weight of 6/95 ± 0/56 grams and weight gain of 2/12 ± 0/64 grams showed the lowest growth rates. The control treatment also showed increased body weight and had the highest average of 337/01 ± 38/62 percent and was significantly different (P<0/05) from the other treatments. Treatment no. 3 with an average of 44/60 ± 15/48 percent had the lowest percentage of weight gain. Treatment no. 2 with an average of 95 percent have the highest rateof survival and was significantly different (P<0/05) from treatment no. 1, but was not significantly different (P≥0/05) compared to other treatments. Treatment no. 1 with an average survival of 55 percent had the lowest survival rate.The results showed that using the green skin of walnuts in the diet can reduce the growth factors in Oscar fish. However, 0.3 percent green skin of walnuts in the diet was most effective in slowing the fish growth rate.

The aim of this study was to determine the importance of gammarid (Pontogammarus maeoticus) in the diet of larval bony fishes, in the Caspian Sea. Sampling of coastal gammarus and larvae was conducted in two phases (December 1389 and April 1390), from 12 stations (in four districts, each with 3 stations) in this study. Fish were caught at 0.5 to 1 meter depth, using a mesh cloth (the aperture diameter of one millimeter) of 0.5 × 1 meter dimension and were immediately fixed with 70 % alcohol and transported to the laboratory. Gammarus were caught from the coast sand using a handmade rectangular fishing net of one mm diameter aperture and 40×60 cm dimension. In the winter of 1389, 98 fish and in the spring of 1390, 107 species of fish were sampled. The sampled specimens included Liza saliens, Rutilus frisi kutum, Atherina boyeri, Benthophilus ctenolepidus, Gasterosteus aculeatus with the weight range of 0.45 – 3.25, 0.6 – 3.27, 0.81 - 5.88, 1.17 – 3.67 and 1.27 – 1.96 gram, respectively. In order to identify the fish species which are consumers of gamarids, gastro intestinal contents were analysed. The results showed that species collected have different amounts of coastal gammarus nourishment. In winter the highest amount with an average of 8.25 percent in 1389, related to Rutilus frisii kutum and in the spring of 1390 with an average of 1.92 percent related to Liza saliens.

This study aimed to determine the most appropriate dose of hydrogen peroxide based on silver colloid for the decapsulation of Urmia Lake Artemia cysts (Artemia urmiana), to achieve the best hatching rate. The cysts were exposed to doses of 0.5, 0.75, 1, 2 and 5% of hydrogen peroxide based on colloidal silver for 30 seconds, 45 seconds, 1, 2 and 5 minutes and 5 ml bleach and pure water (as control) were used to compare the process of decapsulation with the test solutions. After decapsulation, 1 gram of cysts per liter were hatchedat 30 ° C for 48 hours under conditions of 35 ppt salinity. After 48 hours of incubation, 99% hatching rate at a dose of 0.5 % solution of hydrogen based on colloid silver, 97% in bleach solution and 94 % in the control cysts was observed. According to the results of the statistical analysis, ANOVA, significant difference was found between the results of test treatments. The results of this study suggest that, best performance of hatching rate in Artemia urmiana cysts can be achieved, by putting the cysts in a solution with a dose of 0.5% of hydrogen peroxide based on silver colloid.

The aim of this study was to assess protein, lipid, carbohydrate, fiber, ash, and moisture in two species of fishes, Aspius vorax and Carasobarbus luteus, in 2011. Fifteen samples of Carasobarbus luteus and 12 samples of Aspius vorax were collected from the Karkheh River. Mean levels of protein, lipid, ash, moisture in Carasobarbus luteus were 17.19±0.36, 3.23±0.15, 1.28±0.07 and %74.03±0.32, respectively. Similarly, the same chemical contents in Aspius vorax were 18.10±0.36, 2.60±0.20, 1.18±0.09 and %72.10±0.40, respectively. Level of moisture in muscle of two species of Aspius vorax and Carasobarbus luteus were significancantly different (P<0.05), but no significant difference was noticed for protein, ash and lipid (P>0.05). However, Protein in muscle tissue of Aspius vorax was more than Carasobarbus luteus, but lipid, moisture and ash in muscle tissue of Carasobarbus luteus was more than Aspius vorax. Therefore, the results showed that, in terms of animal protein, Aspius vorax is more appropriate compared to Carasobarbus luteus.

In this study, physical and chemical parameters of Behesht- e- Masoumeh wetland water in Qom province, Iran, was studied. For this purpose six points of the pond were sampled, in winter of 1393 followed by summer of 1394. Variables included: temperature, electrical conductivity, salinity, turbidity, nitrite, nitrate, sulfate, phosphate, aluminum, iron, potassium, TDS, pH, BOD and COD. Results showed that the mean concentration of nitrate in summer and in winter were 2.96±2.19 and 0.98±0.78 mg per liter, respectively, hence, nitrate concentration in summer was almost 3 times more than the concentration in winter. Mean concentration of phosphate in summer and winter were 8.21±14.52 and 0.19±0.15 mg per liter, respectively, showing that the phosphate concentration in summer was 43 times more compared with winter. The average of salinity in winter and summer were 11.87±5.59 and 78.38±77.13 mg per liter, respectively. Winter BOD average was 5.68±3.27 mg per liter while in summer was 15.93±14.59. COD average in winter was 45.3±35.69 mg per liter, while in summer was 667.83±921.63 mg per liter. Aluminum average in winter was 0.038±0.0197 mg per liter while in summer was 0.012±0.019 mg per liter. Iron average in winter was 0.08±0.05 , while in summer was 0.309±0.33 mg per liter. The results showed that the levels of all measured parameters including COD, BOD, turbidity, nitrate, phosphate, nitrite, aluminum and iron in winter and levels of turbidity, nitrate, nitrite, aluminum, iron and BOD in summer were less than the limits of national standards of I. R. Iran for wastewater. However, activity, expansion and development of centers like Behesht -e- Masoumeh cemetery and industrial units, can reduce the water quality of Behesht-e-masoumeh pond, by increasing pollution load in surface and underground water and increasing air pollution, too.

This study aims to investigate the effect of vitamin C with in the diet plan of Cyprinus carpio (Koi fish) will result in positive outcomes on the survival, growth performance and hematological parameters of these particular breeds. The purpose of this paper was to increase the production performance of ornamental fish species in the aquaculture with the aim to keep the time and costs to a minimum. In order to achieve these results, the author framed an experiment on 144 Koi fishes in four different groups (one control group and three treatment groups). Later on, all the four groups were fed with vitamin C rich diet (with the doze of, 200, 400, 600 mg per kg of dried ration) for two month. The biometric juveniles (total length and standard weight) of the subjects were measured every 14 days. Moreover, the calculation of growth rate, hematological rates and feeding the subjects were performed at the end of a two month time period. Results showed that addition of vitamin C in diets caused an increase in weight, in control group, whose diets were without vitamin C became in average 1.58 g, treatment 1 in average 1.73 g, treatment 2 in average 2.13 g and treatment 3 in average 4.4 g and increasing weight among groups had significant differences. Survival rates in control group was in average 84%, in treatment 1, 95%, in treatment 2, 95% and in treatment 3 was 97%, but there were no significant differences among groups. In studied fish we faced with increasing percentage of body weight of 39.71% in treatment 3 which has no significant differences with other groups. The most growth rate was assessed in treatment 3 (0.58) and it had significant difference with the control group only. Protein Efficiency Ratio in treatment 3 was in average 2g and it had no significant difference with other groups. There were no significant differences among these groups in number of white blood cells and the most number of white blood cells was assessed in control group.The number of lymphocytes were increased by the increase in the amount of vitamin C and the highest amount was reached in treatment 3, which was 70, but there was no significant difference in number of lymphocytes among groups. Finally based on results in present research, vitamin C with concentration of 600mg in kg in dry diets is recommended for increasing growth performance and hematological parameters in Koi fish.

Classification of coasts entails a general knowledge of the coasts, regarding the characteristics of the waves, tide, sediment and morphodynamics. Chabahar port is very important from the viewpoint of oceanography, political and economical issues. In this research, by using Non-dimensional parameters, reactions of the coastline have been investigated according to the hydrodynamic circumstances, in three stations in Chabahar bay, using field measurements reported by Iranian Ports and Coastal Engineering Organization, from 1992 to 2002, using three methods of Hanson, Hayes and Masselink and Short. Results showed that the tide was semi-diurnal with an average tide range of 2.83 meters, the dominant wave direction was towards southwest, wave break was turbulent and sediment aggregation was fine. In the next stage, using empirical methods the situation of the coast was determined, using Hanson method it was wave - tide, whereas by the classification of Hayes it was a tide dominated (low) and by Masselink and Short classification it was low tide bar in most of the months and in some months ultra-dissipative beaches.