Some aspects of the reproductive biology of Cobitis keyvani (Mousavi-Sabet, Yerli, Vatandoust, Ozeren and Moradkhani, 2012), an endemic Loach fish species from the Talar River in the southern Caspian Sea basin, in north of Iran was studied by regular monthly collections throughout a year. Fecundity, condition factor, gonado-somatic, modified gonado-somatic and Dobriyal indices were estimated. Regression analyses tested the dependence of fecundity on fish length, weight, gonad weight and age. Significant differences were observed between the total number of females and males, females being more abundant. The mature females and males were longer than 49 and 45 mm in total length, and +2 and +1 in age, respectively. The average egg's diameter was 0.56 mm. The spawning of Cobitis keyvani from Talar River took place from May to late July, when the water temperature is between 18.7 to 24.0°C. At the beginning of the reproduction period, the average GSI values were 10.09%, ranging from 6 to 25% in ripe mature females. The absolute and relative fecundity were 2211 and 586 respectively. The absolute fecundity was significantly related to body weight and gonads weight. Based on the gonado-somatic and Dobriyal indices, it was concluded that the fish has a prolonged active reproductive period. Their long reproductive activity and high range of fecundity are types of adaptation by short-lived small fishes to environmental conditions.

Fish Biodiversity were studied at 18 stations in Talar River (one of the major Caspian Sea sub basin) from 1997 to 2004. In this research, 33 species of 14 families were found in the area. Cyprinidae was the most diverse of all families. Diversity of resident fish were more than that of migratory one. Fish species diversity increased toward down stream. According to IUCN, the categories of fish species are:1-Acipenser persicus, Acipenser stellatus and Salma trutta faria: vulnerable (VU) 2-Esoxlucius and Barbus capita: conservation dependent (cd)3- Caspiomyzon wagneri, Barbus lacerta, Barbus mursa, Chalcalburnus charladies and Vimba vimba: near threatened (nt) Most fish species of Talar River, are important in terms of sport fishing.

Classification of water quality is the most important step for controlling the pollution of water. The aim of this study was classifying the water quality of the Talar River basin by analyzing the existing data of six monitoring stations. Multivariate statistical techniques such as cluster analysis (CA), principal component analysis (PCA) and factor analysis (FA) were used to assessment the spatial variations of water quality in the Talar River. The quality data which were gathered from the 2011 to 2014 were included 14 different chemical parameters. . Quality testing stations were included the Pol Sefid, Pol Shahpor, Kiakola, Kari Kola, Savadkuh, Shirgah and Paland Rodbar. The results of cluster analysis of water quality stations were divided into three groups. The first group includes stations Paland Rodbar, Kari Kola, Savadkuh and Pol Shapur, the second group includes stations Shirgah and Kiakola, and the third group was Pol Sefid station. The results of PC and FA showed that the 80 percent of the variations of water quality were done by three parameters; the first parameters are TDS, EC, Cl, So4, Ca, Mg, Na, K, SAR and TH. The second factors are the Po4 and No3, and the third factor is HCo3-. The results showed that the major factors which are polluted the water quality of the Tlar River are related to inflow of industrial, domestic, hospital and agricultural effluents into the Talar River.

Information on erosion and capacity of sediment carrying condition in various basins is one of the subjects that in each of hydrology and river engineering projects should be considered. In the present study HEC- RAS model was applied to evaluate and predict the sedimentation and erosion in the reach of Talar River with 12 km length. For doing this study 40 cross section which was surveyed in 2006 is applied in the simulation and 4 cross section which was surveyed in 2011 applied for calibration of the model. Model calibration and verification showed that the Meyer Peter Muller sediment transport equation has a better fit with the observed results. In order to predict the erosion and sedimentation trend, using recorded data of dischrges in Shirgah hydrometric station during last 30 years and using SAMS Statistical model, the amounts of monthly stream flow was predicted for the next 10 years and then sedimentation model was executed. Variations in the longitudinal profile of river in all profiles showed that the most changes will occurs within the middle reach area and the beginning of the river reach with the length of about 1000m and with having the mild slope is stable. Also predicted amount of sediment outflow from the studied reach is about 348534 tones for the next 10 years.

Introduction: River discharge as one of the most important hydrology factors has avital role in physical, ecological, social and economic processes. So, accurate and reliable prediction and estimation of river discharge have been widely considered by many researchers in different fields such as surface water management, design of hydraulic structures, flood control and ecological studies in spetialand temporal scale. Therefore, in last decades different techniques for short-term and long-term estimation of hourly, daily, monthly and annual discharge have been developed for many years. However, short-term estimation models are less sophisticated and more accurate. Various global and local algorithms have been widely used to estimate hydrologic variables. The current study effort to use Lazy Learning approach to evaluate the adequacy of input data in order to follow the variation of discharge and also simulate next-day discharge in Talar River in Kasilian Basinwhere is located in north of Iran with an area of 66.75 km2. Lazy learning is a local linear modelling approach in which generalization beyond the training data is delayed until a query is made to the system, as opposed to in eager learning, where the system tries to generalize the training data before receiving queries.

The Prediction of alterations and also general and partial transfers of pattern of the river is one of the main subjects concerning fluvial Geomorphology. In this article after introducing Geomorphology of the river and the explanation of study methods of rivers pattern. The Talar river has been examined. First, the path of the river has been divided, considering pattern and then the alterations of pattern has been examined with the use of method of mattematical model and also with the use of Graphic and field methods. aerophotographs taken in 1956 and 1995, were used as well. The result of this examination indicates that the river hasnt reached its own dynamic balance yet and alters at the beginning of plain. At the terminal part, including meanderic pattern, alterations are restricted to the outside bank of bends. But alterations havent been accomplished in general pattern of the river.

About the vital role of Talar river in providing drinking water and acting as a source of agricultural water for the lands next to this river and discharge of various contaminants into this river, quantitative examination of river water seems to be needed. But by providing contaminants zoning and a clear image of quantitative conditions of surface waters by GIS, making any management decisions that will cause direct or indirect environmental impacts on surface waters of the country, become more warily.In this study, which is a kind of sectional study, sampling was done from 6 selected stations (2 upstream stations, 2 middle stream stations and 2 downstream stations) during two periods of high rainfall and low rainfall, in a water year 2012-2013. The results got from laboratory tests were analyzed by quantitative index of NSFWQI and then the path of river was zoned by GIS software.According to NSFWQI, the most suitable conditions belongs to upstream station during high-rainfall period (58, medium condition) and the worst conditions belongs to downstream station during low-rainfall periods (46, bad condition). In accordance to statistical analysis, it became clear that there is a relation between sampling stations and under studied indexes (P-value<0.05).The results of this study showed that among three stations, upstream station water is more suitable for drinking purposes or can be prepared for drinking usages by least treatment and pH adjustment, related to other stations. But the water of other stations must be treated with advanced treatment methods to become acceptable for drinking purposes.

Background and Purpose: The contamination by potentially toxic element (PTE) is a common environmental issue in worldwide rivers. The present study examined PTEs concentration in sediments of Talar River which is one of the main rivers in the Sothern Caspian Basin. Materials and Methods: The sediment samples (n= 44) were collected from top 0–, 5 cm of surface sediment in the main channel and floodplain of Talar River using a Van-Veen grab sampler. The concentrations of trace elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). Principal component analysis (PCA) was used to evaluate possible relationships between the observed variables and source identification. Enrichment factor (EF) was also applied to determine the integrated effects of different elements and evaluate the sediment quality. Results: The average concentration of all elements except Mo were found to be higher than the concentration of elements in upper continental crust (UCC). The result of enrichment factor (EF) indicated that most elements were unpolluted and showed minimal to moderate contamination level. Multivariate statistical analysis indicated Pb, Cu, V, Zn, Cd, Co and Ni typically have anthropogenic sources. Whereas Mn, Sb, Sc, Mo and as showed geogenic source. Conclusion: It was concluded that sediments in Talar River was then experiencing slightly polluted status originated from local anthropogenic sources in the basin which might potentially pose detrimental effects on both ecological and health conditions in the basin.

This study has been done at two stations in Talar river, Mazandaran during Oct. 2008 to Sept. 2009. The purpose of this study was assessment of morphology and population structure of Cobitis taenia in Talar river. Samples were collected and killed using electro shocker (300 V). The fish were fixed in%10 formalin. A total of 410 specimens of Cobitis taenia were examined and 6 meristic and 38 morphometeric factors were investigated. Results showed that in this river the fish has not hard fin rays. The fish has 6 soft rays in dorsal fin and 5 branched rays in anal fin, 39 vertebra, 18 gill rackers and also the average length of head was 10.42 mm. Head width was 5.49 mm and height of head was 6.95 mm, distances between eyes was 3.01 and height of body was 8.46 mm. The length of caudal peduncle was 5.35 and length of dorsal fin was 17.50, height of dorsal fin was 4.64. The length of pectoral fin, length of pectoral fin and height of pectoral fin were 9.77, 3.98 and 7.94 mm respectively. Generally the proportion of fishes has been reviewed. 29% of females and 38.5% of males and 32.4% of immature fishes have been studied. The 4 numerical meristic and 5 morphometric factors had significant differences between two stations (p<0.05) and%30 of the factors had significant differences. The review of population structure of Cobitis taenia has been shown that mean age of the fish has been 1.07 year. The equation for male W=0.671´TL+0.043 and female W=1.593´TL+0.061 has been determined for correlation between total length and total weight of the fish.

Capoeta Capoeta gracilic is one of the native and valuable species in south of basin of from the Caspian Sea. The hematological indexes in fish physiology are influential, so the accurate understanding of blood parameters of this fish can be useful to protect of these valuable stocks. In this research 50 pieces Capoeta capoeta gracilic were collected by Electro shocker from two sampling stations in intermediate area of Talar River. The sampling operation was carried out during the reproduction season and the fish were in four age groups 1, 2, 3 and 4, after blood obtaining in the way on caudal peduncle incision in smaller fish and heart ponxion in larger fish and sex determination and age determination, the amount of some of hematologic parameters Including the total count and subtraction of WBC, the total count of RBC, Hb, Hct, and globule indexes (MCH, MCHC, MCV) were measured manually and with conventional laboratory methods and mean and standard error each of the foresaid parameters in different ages and by gender were determined. The amount of blood parameters regardless age and gender is as follows: The total count of WBC (16359.6±656.3) mm3, the count of RBC (1.581×106±0.08) mm3, Hb (4.41±1.15) g/dl, Hct (38.01±3.16) (%), MCV (187.2±11.99) (fl), MCH (28.09±7.01) (pg), MCHC (15.79±4.64) (%) and in differential count of WBC, percent of neutrophils, lymphocytes, monocytes, eosinophile were 17.05±2.14, 78.54±1.88, 3.43±0.47, 1.2±0.13 (%). The result of statistical analysis did not show signification differences between two sexes (P>0.05). In studying of the effect of the age also showed the hematological factors in different ages do not have significant differences (P>0.05). According to the result assessment and diagnosis physiological status of blood indexes and determination them for estimating, saving and keeping of the Capoeta capoeta gracilis stocks is necessary.