نشریه بوم شناسی منابع آبی
سال سوم شماره 2 (پاییز و زمستان 1398)

Iran, with a wide geographical distribution, has numerous habitats and has high ecological importance. Among the ecological studies, studies on the inland waters of Iran, including the species of the hot springs fishes including Aphanius species, are scarce. Understanding the biology as well as the ecology of different aquatic species in Iran can provide useful information for the effective management of fish stocks in the future. Distribution of Aphanius species is restricted to the central, south and southwestern parts of Iran. This type of distribution of Aphanius species indicates the geological relationship of different basins to each other in past times, and on the other hand, basin separation may limit gene exchange between populations and cause inter populated differences in evolutionary history of this species. Therefore, study of the distribution of these fishes can be used for estimation evaluation and conservation rate of the stocks. This paper discusses various aspects of bio-characteristic of hot springs fishes including their use and economic importance and geographical distribution of carp family in the world as well as Aphanius species with emphasis on identification of A. ginaonis species as the only distinctive species in Iran.

Knowing the zooplankton of any aquatic ecosystem is very effective in managing this ecosystem. This study was a research result in 1391 years. In this study, Zooplankton of four water pools located in Mazandaran province, with the geographical position of "12 ', 68 ° 36 north and" 76 ' 41 ° 53 in the east were studied. Each of the pools was in the area of 3 hectares and rectangular, each of which was mishdend from water wells and under one management. Sampling was sampled by a sampler with mesh size 55-micron, in July, August and September, every 15 days and then data was collected at the Laboratory for identification, counting and data. In the present study, six groups of zooplankton including 1 genus Copepoda, 9 genera Rotifera and 5 genera Protozoa, 1 Cladocera, 1 Mollusca and 2 Cirripedia genuses were identified. The highest percentage of zooplankton groups in hydrothermal pools was related to Protozoa (44%), which belonged to two genera Ciliata with a mean density of 8544.7 ± 7 (number per cubic meter) and Vorticella with a mean density of 5128.05 ± 05 Number in m 3), and since this group of zooplankton was not suitable for feeding, they were not fed to infants, resulting in better conditions for growth, and the rotifers had the most masses, of which Brachionus sp dominated that 65% of this genus is devoted to the relatively good conditions for feeding fish in these pools.

In this study, Given the importance of water quality management of shrimp farms, three farms (three pond per farm) in the northern Tiab area of Minab city of Hormozgan province were studied to evaluate the Environmental conditions of shrimp ponds (Litopenaeus vannamei) during a six-month period (June to December, 2014).The results showed that the ranged water temperature were (15.50C-37.40C), pH (7.1 - 8.97), salinity (41 p.p.t -59.5 p.p.t), dissolved oxygen (0.7 mg.l - 9.5 mg.l), nitrite (0.3 μm.l - 54.5 μm.l), Ammonia (0.01mg.l - 0.13mg.l) and Transparency (10 cm - 95cm) . The results of cluster analysis showed that the water quality has varied between shrimp farms together. The high water temperature and salinity of shrimp farms acts as a negative and limiting factor for shrimp production. Also the water temperature, dissolved oxygen, salinity, Transparency and chlorophyll-a were out of range (permissible limits) in shrimp farms for Litopenaeus vannamei.Avoid increasing shrimp density at surface if poor water quality management is not implemented. On the other hand, increasing the concentration of pollutants in waste water shrimp ponds can cause problems in the future for the coastal environment.

 Fishing nets are designed and manufactured for catching a target fish. Accordingly, the type and size of the netting yarns, strength length of the fishing nets are different. Keeping this strength is important for catching fish. Unfortunately, there is no specific standard for fishing gear in Iran. Therefore, a research was done to investigate strength of Caspian Sea beach seine. For this purpose, 20 samples were collected from net bag and wings of two fishing cooperative in the harvest season of 2014 and 2015. The samples was sent to Amirkabir University of Technology laboratory for study the strength length. The results show that the average of strength of both treatments (new net and used net) in both parts were the highest values. So that, the strength of new net in cod end was 318 kg/f, used net in cod end 295 kg/f, new net in wings 309 kg/f and used net in wings 301 kg/f. The results of one-way ANOVA test show that there was a significant difference among them (P <0.001). In addition, one-way analysis of variance show that there is a significant difference among the mean twist rates in the studied treatments (P <0.001). Studies showed that over time, the strength of this net has reduced, and this decrease was higher in the cod end.

Shrimp farming in Hormozgan province is one of the major industries in the field of aquaculture and shrimp farming area is increasing day to day in Hormozgan province. As the area under farming increases and the amount of storage density in the pond increases, pH changes usually increase and the importance of measuring and controlling its changes is of high importance. Keeping balance and pH changes is one of the key factors in shrimp growth and health. Many factors and factors are important in pH changes in shrimp ponds. The most important factors are soil text, phytoplankton and organisms in the pond and inlet water of the ponds. In order to control and adjust the pH, lime spraying is usually used, and the amount and type of lime used also points to various factors such as lime use, alkalinity (water alkalinity) and other factors. The use of lime should also be proportionate so as not to impair water quality or cause phosphorus deposition in the water and contribute to proper planktonic bloom. In addition to the appropriate pH value for shrimp growth, its variation must be minimal to have the least negative effects on shrimp. In this paper, the importance of pH changes and their changes in shrimp ponds is discussed, and the importance of lime application and alkalinity application in pH changes is briefly discussed

Urmia Lake is the second largest hypersaline lake in the world, covering average 5000 km2 when full. The lake moderates extreme temperatures of the region and many tourists visit it for recreation, swimming and mud treatment during summer. During last two decades, increased demands for agricultural water in the lake's basin and recent droughts have shrunk the lake dramatically, exposing 60-80% of the lake bed. Increasing population, rising the water and food demand, irregular development of agriculture and droughts are considered as the main factors in Urmia lake shrinkage. The most important consequences of the lake retreating are: biodiversity reduction, salt storms occurrences, diseases increasing, tourism vanishing, agriculture weakening, unemployment, migration and low income for local people. This review indicates that increased water demand in the lake basin, recent droughts and global warming are the main drivers for the Urmia Lake shrinkage. The Iranian government has made restoration of this remarkable ecosystem a crucial priority. Here we concluded the causes and consequences of Urmia Lake shrinkage and provide a brief discussion of the impacts on its fauna and flora, coloration, wetlands and islands. As Urmia Lake shrinking persists, many environmental, economic and social advantages will be completely lost in the lake's basin.