نشریه اکوبیولوژی تالاب
سال یازدهم شماره 4 (پیاپی 42، زمستان 1398)

Forests areas of Iran in comparison with the world is very low and this low area is in demolition threat always. Hence, the remainder of these forests should be managed based on ecological capability evaluation. With regard to importance of subject, ecological capability for forestry in the Sharui watershed, Khuzestan province, was evaluated in 2015. For this purpose, the Makhdoom model and AHP method were used. Respectively in first, six information layers including elevation classes, slope, aspect, soil type, vegetation type and density were combined in GIS environment and the final map of environmental unites for forestry was created. Results showed that 197 hectares for forestry has one class capability and respectively 427, 594, 732, 1139, 956 and 115 hectare have the two, three, four, five, six and seven classes’ capability. In the next step the most appropriate measures and options forestry development in the region were selected by using experts and the results of the prioritization criteria, sub-criteria and alternatives, was derived from the software Export Choice 11.The results showed that Among the main criteria of Forestry land use, Physical-chemical factors, Among the sub-criteria, land form, Sources of revenue, Landscape and vegetation type and density, and Among the alternatives, Slope, temperature, soil, river, forest, village, road, water transmission network and Handicrafts, Were more important.

Due to fresh water resource limits and environmental damage caused by aquaculture waste using systems based on sustainable development at the global level is highly regarded. Aquaponics or fish and plant co-culture system is one of the new approaches to achieve aquaculture sustainable development. In this study which was conducted , in 2015, at Ahvaz Azadegan warm water fish culture complex, 6 recirculation aquaponic systems with concrete tanks (400 liters)  as well as 3 one-acre soil ponds(Traditional system) were used to grow common carp. hydroponic systems with  gravel substrate and tank volume ratio of 2:1 for basil (Ocimum Basilicum) culture. In this study common carp fry of mean initial body weight 6.04±0.17 g were randomly distributed in two experimental treatments. Fish were reared at two rearing densities, low density(L): 26 specimens tank-1 (65 fish per cubic meter) and high density(H): 52 specimens tank-1 (130 fish per cubic meter). In 3 one-acre soil ponds , 1100 common carp fish (0.11 fish per cubic meter) were distributed. At the end of the 60-day experimental period in low-density aquaponic system, the final Individual weight was 156.70±11.88 gr and production of 4.07 ± 0.31 kg (10.19 ± 0.77 kg / m3) and aquaponic system with high density, respectively average final Individual weight was 95.75 ± 8.15 gr and production 4.98 ± 0.42 kg (12.45 ± 1.06 kg / m3) and in soil pond average final Individual weight was 447.6 ± 26.7 gr and Production was 488.3 ± 29.1 kg / ha (0.049 ± 0.0029 kg / m3). The production in low and high density aquaponic systems was 200 and 238 times that of pond, respectively.  The economic index in the pond was 1.98 and 2.46, respectively, which indicates a low cost of production of common carp in the soil pond. The water consumed to yield one kilogram common carp in the traditional system was 98 times higher than in the aquaponic systems, indicating a very high water conservation in the aquaponic system. According to the results of this study, using aquaponic system for cultivation of common carp with basil is much more efficient and more effective in saving fresh water consumption , but the economic conversion index of aquaponic system is higher than Traditional system. This fact shows high cost in aquaponic system.

Determining environmental flow is one of the most important topics in the integrated management of water resources for managing river health, establishing Sustainable balance in ecological conditions and preserving life of river bound ecosystems. In this regard in this research, environmental flow of the Ghazmahalleh river in Kordkouy city of Golestan Province was calculated and evaluated using hydrological methods to improve the ecological environment, maintaining the natural regime of the flow and protecting the biological diversity of the ecosystem. Statistics required for hydrological calculations used from information of hydrometry station of Ghazmahalleh during 44 year statistical period (1970 to 2016) with mean annual flow of 0.24 m3/s. Results showed that in order to protect and improve the status of the river at the minimum acceptable bioavailability, FDC Shifting method in management class B with a flow of 0.12 m3/s (51 Percent mean annual flow) in this study due to the consideration of biodiversity management classes and the proper adaptation of the pattern changes within the year of environmental flow and the mean annual flow, priority to other methods and is most acceptable method for estimating environmental flow. In this research proved, results of Tennant method provide lower than the minimum environmental requirement and using this method with imposing stress on the hydrological system, is an inappropriate choice for estimating minimum flow Ghazmahalleh river to maintain the ecological environment. Also Tessmann, Arkansas methods and DRM estimated very low or very high flows of mean flow river. Certainly, allocation amount of environmental flows to these methods provides several problems for different stakeholders from river flow.

The aim of this study was to evaluate the effects of different levels of dietary choline and lipid on growth and feeding parameters and biochemical body composition of common carp Cyprinus carpio. So, 336 common carp with initial average weight of 34.44 ± 0.181 g were held in 24 fiberglass tanks (200L) since September 2016 for 8 weeks. Choline was added to the diet at four levels of 0, 500, 1500 and 3000 mg kg-1 diet with two lipid levels of 5 and 10%. The experimental diets were isonitrogenous. Growth index such as weight gain (WG), specific growth rate (SGR) and viscerosomatic index (VSI) were evaluated and no significant difference was observed among treatments (P>0.05). But, final body weight (FW), feed conversion ratio (FCR) and hepatosomtic index (HSI) showed a significant difference among treatments (P<0.05). The biochemical composition of fillets except lipid was not affected by different levels of dietary lipid and choline (P>0.05). According to the results and considering the amount of choline in the diet, the suitable choline level would be 500 mg kg-1 at 5% lipid in diet.

In this study, age and growth parameters of Prussian carp Carassius gibelio were examined using 222 specimens from the Boostan dam lake and 238 specimens from the Alakoli reservoir. Sampling was carried out monthly from February to September 2015. The ratio was 1:0.13 and 1:0.09 in the study population of Boostan Dam Lake and Alakoli reservoir, respectively. Age determination by scales showed six age groups (1+-6+) for females and three age groups (1+-3+) for males in the Bostan Dam Lake and five age groups (1+-5+) for females and four age groups 1+, 2+, 4+ and 5+ for males in the Alakoli reservoir. The total size distribution varied from 3.3 to 20.6 cm in length and 0.83 to 141.12 g in weight and from 4.3 to 19/6 cm in length and 1.67 to 114.65 g in weight in the Boostan dam lake and Alakoli reservoir respectively. The growth pattern was isometric in males and negative allometric for both females and population in the Boostan Dam Lake and isometric in males and positive allometric for both females and population in the Alakoli reservoir. The parameters of von Bertalanffy growth fit the mean observed total lengths-at-age for each sex separately and were estimated as (L∞= 574.17 cm, k = 0.07 year -1, t0= -0.10 year for females, L∞= 338.43 cm, k = 0.15 year-1, t0= -1.04 year for males, and as L∞= 299.06 cm, k = 0.18 year -1, t0= -0.34 year for combined sexes in the Boostan dam, L∞= 4344 cm, k = 0.01 year -1, t0= -0.12 year for females, L∞= 3177 cm, k = 0.01 year-1, t0= -0.18 year for males, and as L∞= 2526.15 cm, k = 0.04 year -1, t0= -0.40 year for combined sexes in the Alakoli reservoir. The instantaneous growth rate was 1+-2+ ages for population in both regions. Condition factor showed that in the Boostan Dam Lake, the highest value was observed in June and August for females and the lowest in March for males and in the Alakoli reservoir, the highest condition factor was in May for females and the lowest in May for males. This results showed that these values differ in our study with other studies in this field that can be attributed to environmental differences.

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Dorudzan Reservoir supplies a considerable portion of drinking water for Shiraz, hence it is vital to protect its quality. Phytoplankton plays a key role in the cycle of material and energy in aquatic ecosystems, yet no data is available on their diversity and density in Dorudzan reservoir ecosystem. This research investigates phytoplankton communities in 9 stations in the lake, during winter 2015 to autumn 2016. A total of 45 genera of 10 classes were identified, including Chlorophyceae (green algae: 16 genera of 9 families), Cyanophyceae (blue-green algae: 7 genera of 7 families), Bacillariophyceae (diatoms: 13 genera of 6 families), Xanthophyceae (yellow-green algae: 1 genus), Dinophyceae (2 genera of 2 families), Euglenophyceae (2 genera of 2 families), Chrysophyceae (1 genus), Coscinodiscophyceae (1 genus), Trebouxiophyceae (1 genus), and Florideophyceae (1 genus). Species composition and their densities showed variations among different habitats in the lake. The highest density in their seasonal cycle was observed in the autumn (4514/L), and in littoral habitat and riverine section, according to their spatial distribution. Some genera (Ceratium, Dinobryon, Fragilaria, Pediastrum, Spirogyra, and Staurastrum) were present in all seasons. The highest and the lowest diversity of the phytoplankton based on Margalef Index was in summer (1.8) and winter (0.7), and it was lower in the benthic habitat compared to the limnetic and the littoral. In comparison with most of the studied reservoirs in the country, Phytoplankton diversity is higher in the Dorudzan. As the green algae and diatoms were observed in all seasons, and blue-green algae never bloomed, from the point of the density of various phytoplankton, this reservoir might be regarded as an oligotrophic lake. Results of this research suggest that the seasonal and spatial distribution and density of phytoplankton in Dorudzan Reservoir is quite specific, due to its different water temperature situation, and specific availability of nutrients in various layers.

Today, freshwater resources, including rivers and lakes, are considered as an important source of water at risk of pollution from human activities, such as the outflow of fish. In this study, the effect of two species of Phragmites australis and Cyperus rotundus and their effects on water quality changes such as nitrate, ammonia, and phosphate in the Breeding of common carp were used. In this regard, 90 species of both species, reed plants with initial weights of 100 ± 10 grand nut sedge strain with an initial weight of 30 ± 5 in six channels of 120 liters (30 plants per channel) were treated. One hundred kilograms of common carp with a mean weight of 20-2.3 g was introduced into a tank with a capacity of 1000 liters dewatering during the 42-day trial period. The results showed that the average final weight of fish was 35 ± 5 and the mean weight of each plant was 50 ± 500 g and the mean weight of the nutsedge plant was 10 ± 100 g. Water quality analysis showed that there was a significant difference between the input of fish tanker water and the output water of plant cultivars (P <0.05). Based on the reduced rate of high concentrations, the best remaining time was selected in the fourth week. Also, the results showed a significant difference between the outputs of the treatments in terms of improving the quality factors of water at a probability level of 5%. On the other hand, with a significant interaction between treatment output over different periods can be understood that the plant material selected as the filters have a high potential to absorb nitrates, nitrite, ammonium, and phosphates.

Aras River is one of the largest rivers of Caspian Sea Basin in Northwest of Iran which plays an important role in regional water supply for various uses. This study executed in area from Siahrood to Aras Dam Lake in the summer of 2017. Sampling, identification, enumeration and recording demographic changes in different terms of growth season was performed for each of 7 stations for three months. Identified genera (32 genera) belong to Bascillariophyta, Chlorophyta, Cyanophyta and Dinophyta. Diatoms with 18 genera, chlorophyta with 8 genera, Cyanophyta with 5 genera and then Dinophyta with one genus were most dominant phylum in Aras River, respectively. The highest algae density at the beginning and end of the growing season was due to the Navicula genus of Bascillariophyta and the Oedogonium genus of the Chlorophyta phylum.