35 research outputs found

    Factors affecting phytoplankton fluctuations in the Persian Gulf (Bushehr coastal waters) during winter and spring 2012 - 2013

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    In this study, surface water samples were collected monthly from five stations inclduing Nayband Bay, Assaloye, Dayer, Kabgan and Bushehr from December 2012 to June 2013. Sampling stations were chosen according to data being collected during algal bloom caused by Cochlodinium polykrikoides in 2008. A total of 45 genera of phytoplankton belongs to four classes were totally identified accounting for 53 species of Bacilariophyceae, 32 species of Dinophyceae, one genus of Euglenophyceae, and one genus of Cyanophyceae. Bacilariophyceae with 89.5% was the most abundant family followed by Dinophyceae with 9.03%, Cyanophyceae with 1.25 % and Euglenophyceae with 0.22 %, respectively. The highest phytoplankton abundance was observed in Bushehr and Nayband Bay stations. In addition to statistical tests, Shannon (Shanon-Winner) and dominance indices were investigated. The lowest variability for Shannon index (1.90) was recorded in Bushehr Station in comparison with other stations. The highest Shanon index was in Dayer station (2.90) with the increase of diversity in Dinophyceae. Evidence of coastal pollution in Dayer along with nutrient inputs from land might be effective in increasing the Shannon index. At 80-90% simmilarity, the results of Cluster analysis separated Dayer station from other stations. It seems that a part of uniformity in phytoplankton abundance is affected by the mild conditions of ambient temperature. The total diversity of phytoplankton in the study area was low. The relative moderation of temperature seems to have contributed to the dominance of diatoms. Yet, the increased volume dust (as emerged by the increased dusty days per year) and the introduction of its accumulation in the Persian Gulf waters, along with other pollutants on phytoplankton communities might be underlaying factors for the dominace of diatoms in the study area

    The core of pomegranate (Punica granatum) seed kernel meal effects of growth parameters of rainbow trout (Oncorhynchus mykiss)

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    This study was aimed to investigate the effects of pomegranate (Punica granatum) seed kernel meal (pskm) as a supplement in the diet of rainbow trout (Oncorhynchus mykiss), The experiment was carried out in growth in a period of 90 days since the 12/11/2014 until the 12/03/2015 in Abzi Eksir Koesar complex , situated in south east of Tehran. 600 fingerlings with average weight of 6.74 gram and average length of 5.50 centimeter were divided to five treatments, The control group was without any pskm, and the other groups with added 1, 2, 3 and 4 percent pskm Respectively. For greater certainty each treatments had three replicates. Result indicated that pskm caused highest increased growth parameters in treatment 3 with 3 percent pskm, with other treatments and groups. growth parameters including weight with maximum of 47.74 gram, length were 15.03 centimeter, weight gain with maximum of 41.15 gram, length increase with the maximum of 9.71 centimeter, Weight gain percentage with maximum amount of 572.1, specific growth rate with 0.45 and specific length rate with 0.1 mm. All growth parameters with the best value was seen in treatments 3. This result is due to the presence of high levels of appetite stimulants such as polyphenols of pskm (p<0.05). Result also indicated that the level of pskm in treatment 4, did not cause enough different with the control group, mainly because of higher amount of tannin in their diet

    Comparison of muscular tissue composition of rainbow trout in brackish and different salinity waters

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    In this research, controlled changes of rainbow trout muscular composition cultured in brackish water (14.1ppt) and freshwater (4.3ppt) was compared. Some 180 juvenile rainbow trout with a weight of 47.2±0.1g each were released in 6 polyethylene tanks with a capacity of 1.5m³. During the experiment, water temperature was kept constant. Feeding fish was conducted using common Faradaneh food and considering water temperature and fish biomass. After 126 days, fishes attained around 320±20g of weight, were sampled and taken to laboratory and the amount of protein, fat, ash, minerals and moisture in their muscle tissue were measured. Results showed amount of fat and dry matter in brackish water cultured fishes is less than those cultured in freshwater. The average percentage of protein and minerals in brackish freshwater cultured fishes were significantly different and the average percentage of moisture in brackish water cultured fish was higher than those of the freshwater fish

    Growth comparison between post-larvae from cultured and wild spawners of Indian white shrimp, Penaeus indicus, in commercial farms in north Persian Gulf, Bushehr, Iran

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    Post larvae of wild and cultured spawners of the Indian white shrimp (Penaeus indicus, Milne Edwards, 1837) were reared to market size, in commercial ponds of shrimp farming site of Helleh, in Bushehr Province, during a six months period. Environmental factors, management process and the diet used to feed shrimps were almost similar for both treatments. Averages of the weight, length, specific growth rate, food conversion ratio and survival rate were measured and compared between the two treatments at harvesting time. Results indicated that, the post larvae of wild spawners had better growth, higher survival rate, and lower food conversion ratio. Weight gain of abdominal portion of the body, was higher in wild post larvae (P<0.01), which was in contrast to cephalothorax weight (P<0.01). Length-weight relationship measurements illustrated that, cultured post larvae obtained from wild spawners had similar size and were more acceptable for the market. Broodstock background could be the main reason for given differences, in which, those captured from the sea, had better condition due to receiving appropriate food with higher genetic diversity. To produce high quality post larvae for the expanding shrimp farming industry as an economic activity in the country, it is suggested that broodstocks to be obtained either from the sea as sub-adults or matured spawners, or to be provide from culturing shrimps, raised in conditions closest to the nature (i.e., ambient factors, prepared diets) and also with appropriate genetic diversity

    Density assessment of muddy shore crabs in the eastern part of Bandar Abbas

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    Crabs of intertidal zone of a muddy shore in Bandar Abbas were studied using monthly examination of Goharshad and Terminal stations during August 2005 to July 2006. Sampling was done by Corer and 14 species from 6 families were identified. Crabs were from Ocypodidae, Pinnotheridae, Pilumnidae, Trapeziidae, Leucosiidae and Varunidae families. Results showed Ocypodidae, the most abundant and diverse with 1196 individuals/m^2, was more abundant but less diverse in Goharshad station compared to Terminal which could be attributed to the urban pollution in Terminal station. Pinnotheridae with 64 individuals/m 2 showed an adaptation to organic materials but was not resistant to being out of water. Pilumnidae and Trapeziidae were found in small numbers in the stattions. Genus Ebalia from Leucosiidae with 27.18 individuals/m^2 showed positive reaction to organic materials and was resistant to being out of water. Varunidae were present with a few specimens probably because of human disturbance or speed in burrowing and escaping from sampling. Because civic pollution enter Terminal station, The results of this research showed that crabs react to urban pollution and hence are suitable as environmental indicators

    A study on growth parameters, blood factors and proximate composition of rainbow trout (Oncorhynchus mykiss) cultured in underground brackish and freshwater

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    In this research, growth rate, blood parameters and proximate composition of rainbow trout (Oncorhynchus mykiss) cultured in brackish and freshwater were evaluated. Two treatments (brackish and freshwater) in 3 replications were investigated. Six 1.5 m³ fiberglass tanks were used for this experiment, containing 180 rainbow trout specimens with average weight of 47.2±0.1g. Feeding rate in treatments was about 3% of body weight based on water temperature and fish biomass. Total length and weight of fish were measured in 15 days intervals. After 135 days of culture period, some fish samples were transferred to the Lab. Blood were directly collected from the heart. Muscle composition was analyzed for proximate composition. The results showed that the body weight of samples in brackish water was increased significantly after 45 days of culture period. Blood factors including WBC, RBC, Hb, Hct, MCV, MCH, MCHC, lymphocyte, thrombocyte and concentration of K+ ions in fish cultured in brackish water showed a significant increase (P<0.05). Muscle composition analysis showed a significant increasing (p<0.05) in fat and dry matter in freshwater treatment, while moisture was significantly higher in brackish water (P<0.01)

    Study of possibilities of aquaculture activities in the Gorgan Bay

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    The Gorgan Bay has situated in the South east of the Caspian Sea and water entersthe Bay from the Sea .it covers an area about 450 squar kilometers that is connected to the sea only by the passage of Ashouradeh in the north east of the bay . The water balance is almost constant and is not tidal. In this study, a model made for the bay on the basis of its water quality and quantity. Its reactions evaluated under different qualified scenarios and its surrounding water quality survey during next 29 years. Mike 21 software was used for 2 dimensional modeling . At first hydrodynamic modeling of the bay was done .one of the important factor was water depth which calculated by hydrography method of the bay. Then, a model made for the salinity of the bay. Since, salinity is a stable parameter, a sub-program TM (Mike 21) which has the ability to make a model from the process of advection – dispersion was used. The amount of Manning (0.025) and Dispersion (50) coefficient calculated simultaneously with calibration of salinity model (D:square meter / second). Results from data verification of salinity model indicated about 3 percent mean error. The pollution dispersion type in the bay evaluated at six points of the bay using the method of dot constant source of pollution. Results showed that around 99.9 percent of pollution decreases under the effect of dilution process till the 100 m distance. Then modeling of dissolved oxygen, Ammonia, nitrite and nitrate was done by using of subprogram ECOLAB at the Mike software To make these models, first the sensitivity analysis of these parameters was done. Important parameters chose for model calibration and then data verified and also the model calibrated. The result of data verification test showed the mean error of oxygen, ammonia, nitrite and nitrate were respectively about 3, 4, 6.3 and 37 percent. Then modeling made according to four different scenarios which defined on the basis of pollutions originated from aquaculture in the bay (scenario 1: aquaculture at the first half year. Scenario 2: aquaculture at the 2nd half year. Scenario 3: aquaculture at the whole of year. Scenario 4: cultivation of bluga for 3 years). Water quality of the bay and also different amount of aquaculture production surveyed during next 29 years under different scenarios of aquacultures. The places under pollution were included the appropriate places for aquacultures in each scenario that was already determined at the bay .Then the reaction of the Gorgan bay was determined under each scenario. The curves of pollution fluctuations were drawn along with amount of cultivation at the each scenario. At last, appropriate amount of cultivation was calculated at each scenario with considering of self-purification of the bay that does not tend to pollution of the bay. On the other hand, the farms arrange, distances between farms and the number of cultivation ponds at the each farm was calculated. Finally, results showed that the aquaculture capacity of the bay is less than 300 tons per year

    The fluctuations of physicochemical factors and phytoplankton populations of Urmia Lake, Iran

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    Urmia Lake is one of the two large hypersaline lakes in the world which have Artemia. It is located in northwest of Iran. Due to a decrease in water inflow and volume, the salinity of Urmia Lake has reached to more than 300 g.l-1 since 2001. The increased salinity has greatly influenced biological aspects of the lake, and caused the lake undergoes at critical conduction. The aim of the present study was to investigate the distribution fluctuations of phytoplanktons and selected physicochemical factors in relation to Artemia distribution in Urmia Lake during 8 months. Statistical analysis of mean values of ion concentrations and phytoplankton abundance indicated significant differences among sampling months. The minimum and maximum values for the selected factors were, as Cl- 176.2-201.3 g.l-1 , CO2 95-175mg.l-1 , dissolved oxygen (DO) 0.1-2.8 mg.l-1 , HCO3 - 144-496 mg.l-1 , PO42+ 104-875 mg.l-1, NO3- 330-4104 mg.l-1, NO2- 4-21.5 mg.l-1, SO42- 10490-29840 mg.l-1, Ca2+ 561-1606 mg.l-1, Mg2+ 3649-14587 mg.l-1 while water hardness was 21000- 62000 mg.l-1. Fourteen phytoplankton genera included Bacillariophyceae (10 genera),Chlorophyceae (2 genera) and Cyanophyceae (2 genera) were identified during sampling period. The smallest average density of phytoplankton 97249 L-1 was observed in December 2005 and the greatest average density 481983 L-1 in August 2005. Dunaliella sp. composed 92.1% of the lake's phytoplankton. Statistical analysis of phytoplanktons fluctuations showed a significant difference among different months (p< 0.05)

    A study on physico-chemicals parameters, environmental pollutants, bacterial and macrobentos distribution at the surface waters, undergrand waters and wastewater of Mangol Dam basin (Mazandaran province)

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    At the present study, the water quality parameters monthly, environmental pollutants (pesticides, heavy metals and surfactants) seasonally, macrobenthos and bacteria (monthly) were done 2009 t0 2010 that located in Mangol Dam with longitude and latitude 52° 22' 49" N and 43° 15' 43" E, respectively. All water samples were collected from under-groundwater, surface water and wastewater in 12 stations and the results are as follow: The mean concentrations of DO, BOD_5, COD, HCO^3-, CO_3^2-, TA, Ca^2+, Mg^2+, TH, TSS, TDS, Cl^-, PO4^3-, NH^4+, NO^2- and NO^3- were determined about 11.86±0.49, 5.95±0.11, 4.96±0.59, 28.1±6.1, 14.34±1.64, 36.30±2.33, 64.66±2.34, 28.84±1.52, 271.62±8.41, 0.37±0.03, 0.45±0.02, 28.02±1.96, 0.06±0.01, 0.010±0.001, 0.01±0.001 and 0.96±0.03 mg/l, respectively and also temperature, pH and EC were 12.7±0.61°C, 8.00±0.02 unit, 0.57±0.02 ms/cm in all samples. The surface water quality of Haraz River and its tributaries were suitable for usual applications such as aquatic matters, but based on BOD_5 need to more attention for human usages. The water quality index (WQI) of surface water was classified in group II at all stations that shows serious water quality changes due to domestic and agriculture sewage. The groundwater was affected by different matters that caused change of water quality parameters. The wastewater was classified from good to moderate based on BOD5. The quality of wastewater was declined at down-stream with decreasing DO and pH and increasing BOD5 pollutants. The mean concentrations of aldrin and endrin were about 0.66 ± 0.59 and 0.71 ± 1.07 µg/l, respectively. The maximum seasonal concentration of organochlorin pesticides (OCPs) were detected in fall, winter and spring for endosulfan sulfate, γ-BHC, heptachlor, endrin aldehyde compounds about 2.85, 0.34, 0.14 and 0.14µg/l, respectively. The maximum seasonal percentage range of OCPs in fall, winter and spring for endosulfan sulfate, DDD and β-BHC were 42, 25 and 25 %, respectively. The maximum seasonal concentrations during fall, winter and spring were detected in Sorkhroud and Polechelave stations for only Fe about 1.48, 3.3 and 8.22 µg/l, respectively. Also for Hg in spring was determined about 17.2 mg/l. The mean concentration of Zn, Fe and Hg in water sampled were 0.23 ± 1.01 and 1.21 ± 2.00 µg/l, respectively and 4.65± 6.38 mg/l. The maximum concentration of linear alkyl benzene sulfonate (LAS) in summer was 971µg/l. The mean concentration of surfactant during fall, winter, spring and summer was 418.62 ± 52.16 µg/l. The maximum seasonal percentage ranges of surfactant during fall, winter, spring and summer in all stations of sampling were 76, 76, 100 and 100 %, respectively. Tottaly 15 families of macrobenthos were identified in Haraz River. The maximum mean of abundance and biomass in Sorkhroud and Nour-roud stations were 1177±256 ind/m^2 and 3609±935mg/m^2, respectively. During Seasons, the maximum mean abundance and biomass were detected in fall and winter with 1185±444 ind/m^2 and 3891±849 mg/m^2, respectively. Water quality were classified by Hilsenhoff Biotic Index such as Sorkhrood station as "Very Poor", Isar town station as "Fairly Poor" and Karesang and Nor-roud stations as "good" qualification. The maximum of total coli forms and fecal coli forms in surface water were observed in Sorkhrood about 4.9 and 2.3CFU/100ml, respectively. The maximum of total coli forms and fecal coli forms in groundwater were observed in Halomsar and Absak stations about 4 and 1.7CFU/100ml, respectively. Maximum of total coli forms and fecal coli forms in wastewater were observed in Nor-roud station about 3.1 and 1.6CFU/100ml, respectively. The Ovary of nematode in wastewater were observed in Nor-roud and Isar Town stations about 30 through 124, respectively
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