South Caspian Sea Research Articles

Distribution and composition pattern of polycyclic aromatic hydrocarbons in different tissues of sturgeons collected from Iranian coastline of the Caspian Sea

The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the liver, kidney, gills and muscle tissues of Persian sturgeon (Acipenser persicus; n=16), and Stellate sturgeon (Acipenser stellatus; n=7) collected from coastal waters of the South Caspian Sea from March and April 2011. The distribution and composition pattern of PAHs in the different tissues of sturgeons, and the effects of lipid content in sturgeon tissues and the octanol–water partition coefficient (Kow) of PAHs congeners on them were analyzed. The levels of total PAHs in the various tissues of Persian sturgeon and Stellate sturgeon ranged from 2.095 to 6.587 and 1.942 to 6.206μgg−1dw, respectively. Stellate sturgeon showed significantly higher levels of heavy PAHs (⩾4-rings) than Persian sturgeon. The analysis has revealed a high degree of differential accumulation of the studied PAHs in the tissues of the both species. Low molecular weight PAHs predominated in the sturgeons, accounting for 81.89% of the total PAHs. Among the sixteen tested PAHs, naphthalene was the most dominant congener, followed by phenanthrene and fluorene. The PAHs levels and distribution in the tissues of sturgeons are dependent on both the Kow of PAH congeners and the lipid content in these tissues. There was a significant positive relationship (r=0.868, p<0.005) between lipid content and PAHs levels. The statistically significant negative relationships (p<0.01) were found between log Kow and log-transformed PAHs levels for muscle tissues of both sturgeon species.

Heavy metals in selected tissues and histopathological changes in liver and kidney of common moorhen (Gallinula chloropus) from Anzali Wetland, the south Caspian Sea, Iran

The present study aimed to measure the concentrations of Sn, Pb, Zn, Hg, Cu, Ni and Cd in the muscle and liver of 40 Common Moorhens (Gallinula chloropus) hunted from four stations in Anzali Wetland (Pirbazar, Ghalam-Koudeh, Selkeh and Abkenar). The histopathologic alteration index (HAI) of liver and kidney was also assessed in these birds. The highest concentrations of selected metals were measured in the liver of birds collected from Ghalam-Koudeh (Pb: 4.59±0.21, Sn: 6.663±0.282, Zn: 29.867±2.011, Cu: 24.07±1.84, Hg: 7.5±0.257, Ni: 6.85±0.52, Cd: 1.879±0.4mg kg−1 dw). The lowest concentrations of metals were measured in the muscle of birds caught from Abkenar (Pb: 0.799±0.207, Sn: 1.873±0.066, Zn: 18.533±1.582, Hg: 0.86±0.08, Ni: 0.53±0.117, Cu: 6.63±1.114, Cd: 0.08±0.002mg kg−1 dw). Also the highest and lowest concentrations of metals were recorded in sediment of Ghalam-Koudeh and Abkenar stations, respectively. These stations were located next to multi-industry Anzali Port. However, the concentration of Sn and Zn in sediment and tissues of Common Moorhens collected from different stations was lower than the permissible limit suggested by WHO and Canadian Council of Ministers of the Environment (CCME). But, Pb, Hg and Ni concentration in sediment and birds caught from all stations was higher than the permissible limit defined by WHO and CCME. Cu and Cd concentration in tissue samples and sediment of Ghalam-Koudeh and Pirbazar was also higher than the permissible limit defined by WHO and CCME. Hemorrhage, melanomacrophage aggregations, sinusoidal congestion and hepatocyte vacuolation were the most pathological changes found in the liver. Reduction of the Bowman space, melanomacrophage aggregations and hemorrhage also were observed in the kidney. The HAI means of G. chloropus collected from Ghalam-Koudeh and Pirbazar were significantly higher than other sites. Based on the HAI values and metal bioaccumulation in the tissues of G. chloropus, Ghalam-Koudeh and Pirbazar could be considered as having the worst environmental quality.

Abundance Of The Alien Spionid Streblospio gynobranchiata In Relation To Sediment Composition Along The Southern Coast Of The Caspian Sea

Abstract Seasonal and inter-annual variations in the density of the invasive polychaete Streblospio gynobranchiata were noted in the south Caspian Sea when sediment conditions were examined at five and 14 meters depths in 2005 and 2010. There was no clear trend in changing density in line one but in line two, in all seasons except summer, density of S. gynobranchiata decreased significantly. Maximum densities of 2,040 ind./m−2 and 1,013 ind./m−2 were obtained in 2005 and 2010, respectively. Although the percentage of total organic matter as a food resource increased from 2005 to 2010, the density of S. gynobranchiata decreased slightly in the same period. It seems that in this invasion phase the population of S. gynobranchiata has decreased to a balance condition. There is evidence that the changing density of this species is also being affected by other biotic/abiotic factors like intra/interspecific competitors and pollutants.

Validation of lateral fluid flow in an overpressured sand-shale sequence during development of Azeri-Chirag-Gunashli oil field and Shah Deniz gas field: South Caspian Basin, Azerbaijan

Data collected over the past 15 years from exploration, appraisal and production in the offshore South Caspian Sea validates the previously developed model of lateral fluid flow from the overpressured basin center to the basin margins within the sandstone aquifers of the Pliocene Productive Series. Specifically, new data confirm the predictions that 1) although both sandstones and shales are overpressured, sandstones are generally less overpressured than shales, 2) there is a lateral, regional gradient in sandstone overpressure, decreasing from the basin center to the basin margin and 3) the impact on the pressure field from local features such as mud volcanoes or local faults is limited. Additional pressure data, combined with regional seismic mapping, suggests variations in lateral fluid flow in different stratigraphic intervals. These data show that the less continuous sandstones of the upper and lower Productive Series are closer to the surrounding shale pressures as they are less well connected to the basin margin outlet, whereas, continuous sandstones in the middle Productive Series show the highest amount of lateral pressure transfer from the basin center and are therefore at lower pressures than the surrounding shales. Pressure data from development wells at the Azer-Chirag-Gunashli oil field and the Shah Deniz gas-condensate field reveal local variations in sandstone and shale overpressure resulting from the lateral pressure transfer affect (Traugott and Heppard, 1994; Traugott, 1996; Swarbrick and Osborne, 1998; Yardley and Swarbrick, 2000). Across large, high relief structures, well-connected sandstones transmit fluid pressures from the adjacent, deep overpressured synclines into the shallower crest of the structure. Pressures in sandstones decrease updip along a hydrostatic gradient (0.433 psi/ft). The pressure gradient in the shales however, will change according to the shale overpressure gradient. In the South Caspian Basin the overpressure gradient in the shales varies between 0.6 and 0.9 psi/ft. Therefore, the relative overpressure between the sandstones and shales varies along structural dip. There are a number of important implications to exploration, appraisal, and development because of large scale lateral fluid flow. Lateral fluid flow has consequences for the sealing capacity of sandstone reservoirs and the variable position of hydrocarbon –to- water contacts around a structural accumulation. This requires each sandstone–shale couplet be considered separately for pore pressure prediction. Basin-scale 3D models were constructed to better understand the implications of basin-scale fluid flow within and between individual reservoirs at each structure.

The effective elastic thickness of the lithosphere in the collision zone between Arabia and Eurasia in Iran

The effective elastic thickness, Te, has been calculated in the collision zone between Arabia and Eurasia in Iran from the wavelet coherence. The wavelet coherence is calculated from Bouguer anomalies and topography data using the isotropic fan wavelet method, and gives Te values between 14.2 and 62.2km. The lower value is found in the Central Iranian Blocks and the East Iranian Belt which are bounded by several large strike-slip faults with lithospheric origin. The higher value occurs in the east of the South Caspian Sea Basin. The resulting Te map shows positive and negative correlation with shear wave velocity and surface heat flow, respectively. A comparison between the seismogenic thickness (Ts) and Te in Iran suggests that Te>Ts. Results of the load ratio in Iran indicate that in most of the study area surface loads are much more prevalent than subsurface loads, except in the Central Iranian Blocks and NW of Iran. Intermediate to low Te values in Iran were inherited from multiple rifting and orogenic activities from Late Precambrian (∼650Ma) to present day which are not only reflected in thin and warm lithosphere but also an increasing seismicity rate.

Modelling seasonal circulation and thermohaline structure of the Caspian Sea

Abstract. The wind- and buoyancy-driven seasonal circulation of the Caspian Sea is investigated for a better understanding of its basin-wide and mesoscale dynamics, mixing and transport. The model successfully reproduces the following basic elements of the circulation: the southward-flowing current systems along the eastern and western coasts, the upwelling along the eastern coast, the cyclonic circulation in the Middle Caspian Sea (MCS), especially in winter, and the cyclonic and anticyclonic cells of circulation in the South Caspian Sea (SCS). The observed seasonal variability of sea level and sea surface temperature (SST) is well reproduced. Mesoscale structures, not always evident from hydrographic observations, are identified.

Structural evolution of the Kopeh Dagh fold-and-thrust belt (NE Iran) and interactions with the South Caspian Sea Basin and Amu Darya Basin

We present a detailed stratigraphic and structural study of the Kopeh Dagh fold-and-thrust belt in NE Iran, which is an investigation of the complex polyphased tectonic history of this belt and its links with the adjacent South Caspian Sea and Amu Darya basins. Based on numerous field surveys, a large amount of 2D and 3D seismic data, borehole data and more than 150 new biostratigaphic datings, a new detailed biostratigraphic chart and 4 main regional cross-sections illustrate the importance of lateral facies variations and structural inheritance in the present-day structure of the belt.After the Cimmerian orogeny corresponding to the closure of the Paleotethys Ocean in Late Triassic/Early Jurassic times, a Middle Jurassic post-collisional rifting event was associated with the deposition of one of the main source rocks of the Kopeh Dagh and the Amu Darya Basin (Kashafrud Formation). Following this rifting event, over 7 km of sediments were accumulated until the Tertiary above a regional post-Triassic unconformity. The occurrence of local uplifts during the Late Cretaceous-Early Paleocene is interpreted as a consequence of regional-scale modification of plate-slab coupling in the Neotethys subduction zone. The main inversion of the Kopeh Dagh occurred at Late Eocene times, when the far-field deformation developed in Eurasia as a consequence of the locking of the Neo-Tethys subduction. This folding phase is sealed in the western part of the belt by a major Eocene-Oligocene unconformity at the base of the thick sedimentary series belonging to the South Caspian Sea Basin. The bulk of sedimentary infill in the South Caspian Sea Basin is Oligocene and younger, and it is probably related to syn-compressional downward flexure of the resistant basement basin at the onset of the Alpine phase. In the eastern part of the Kopeh Dagh, this deformation is characterized by Middle Jurassic graben inversion with evidence of forced folding, short-cuts and as well by larger scale basement uplifts. In contrast, the northwestern part of the belt shows thrust faults involving basement and fault-propagation folds within the sedimentary sequence. The Kopeh Dagh presents tectonic structures that are parallel to the Paleotethys suture zone, which emphasizes the importance of the structural inheritance and inversion processes during the structural evolution of the belt. Finally, a change from a mostly dip-slip to a mostly strike-slip tectonics occurred during the Pliocene within the Kopeh Dagh as a consequence of a major tectonic reorganization in North-East Iran.

Seismic reservoir characterization of a deep water sandstone reservoir using hydraulic and electrical flow units: A case study from the Shah Deniz gas field, the South Caspian Sea

Abstract Seismic reservoir characterization of deep water sandstones using hydraulic and electrical flow units plays an important role in delineation of oil and gas traps in the Caspian Sea basin. The proposed methodology of this study comprises two major steps. Firstly, the reservoir rock types, including Hydraulic Flow Units (HFUs) and Electrical Flow Units (EFUs) are estimated from petrophysical data. Secondly, seismic data are converted into HFUs and EFUs by using the seismic attributes technology in conjunction with the neural networks and fuzzy clustering algorithms. Optimal seismic attributes for the estimation of Current Zone Index (CZI) and Flow Zone Indicator (FZI) include acoustic impedance, which was derived from a model based inversion, together with dominant frequency and amplitude envelope data. High porosity and permeability zones are delineated by using the seismic derived flow zone indicator data. Since there is a strong correlation between water saturation and current zone indicator, hydrocarbon saturation changes within the sandstone packages are investigated by using the EFU model. The integrated approach introduced in this study is successful in highlighting high porosity and low water saturations zones of the Shah Deniz sandstone packages.

Latest Diversity Trend and Seasonal Abundance of Population of Zooplankton (Holoplankton) Communities in the South Caspian Sea, Iran

Seasonal variations of zooplankton communities were studied in the southern Caspian Sea for 4 successive seasons and 8 transects with 5 stations from 5 to 100 m depths which sampled during 2009. The zooplankton population constituted of 73.33% copepods, 24.21% rotifers, 2.23% cladocerans and 0.23% protozoans. Copepods were dominant at all stations with a density between 1456±531 ind. m -3 (Transect 8) to 4524±1215 ind. m -3 (transect 2). The predominant species of copepods was Acartia tonsa constituting 99.50% of all copepod populations. They were most abundant during warm months of summer in the upper layers (surface to 20 m depth) while rotifers replaced them during cold season. The maximum density of zooplankton was observed in the west decreasing towards the eastern parts of the sea.

Population structure and variation in Persian sturgeon (Acipenser percicus ) from the Caspian Sea as determind from mitochondrial DNA sequences of the control region

Mitochondria1 DNA (mtDNA) control region sequences were analyzed to evaluate the population genetic structure of Persian sturgeon (Acipenser persicus) in Caspian Sea. A total of 45 specimens were collected from the different locations of the Caspian Sea. MtDNA control region was amplified using PCR. Direct sequencing was performed according standard method. The results showed that 12 haplotypes were observed between 45 samples in the method. The highest numbers of haplotypes were observed in Sefidroud River in which 3 haplotypes A, B and E among them were specific for the river and were not observed in the other locations. The average haplotype diversity (h) and nucleotide diversity (π) were 0.795±0.037 and 0.0062±0.0046, respectively. The results of FST based on kimura- 2 parameters method and analysis of molecular variance (AMOVA) demonstrated that most variations occurred between samples from Sefidroud River in the south Caspian Sea and that the samples include three distinct populations including Sefidrud, Russia and Azerbaijan (P<0.001). As mtDNA control region is hypervariable segment, this can be provide potential marker for identifying probable populations and for determining their management and conservation units, leading to the useful application of molecular genetics in investigating conservation biology of the Persian sturgeon.

Effect of Frozen Storage on Quality Changes of Five Fish Species from South Caspian Sea

Fish and fishery products can undergo undesirable changes during frozen storage and deterioration may limit the storage time. These changes result from lipid oxidation and enzymatic hydrolysis of lipid and protein. Approach: The quality changes (total lipids, primary and secondary lipid oxidation products as well as lipid and protein hydrolysis) in Caspian kutum, golden grey mullet, common carp, pike perch, and common kilka during frozen storage (-24 °C and a 6 month period) were examined. The statistical result showed that among all of fish species the highest lipid content belonged to the fresh samples and the least value was recorded for those stored for 6 months. The damage indices tested such as peroxide value (PV), thiobarbituric acid (TBA), free fatty acid (FFA) and total volatile nitrogen (TVN) during frozen storage revealed significant (P ≤0.01) correlation with the storage time. The changes in lipid oxidation indices (PV and TBA) and enzymatic deterioration indices (FFA and TVN) show that all the fish species are susceptible to significant change during the frozen storage, especially if the storage time is long and can be stored for five months in a frozen state with low undesirable changes of lipid and protein quality.

Caspian sea-level changes during the last millennium: historical and geological evidence from the south Caspian Sea

Abstract. Historical literature may constitute a valuable source of information to reconstruct sea-level changes. Here, historical documents and geological records have been combined to reconstruct Caspian sea-level (CSL) changes during the last millennium. In addition to a comprehensive literature review, new data from two short sediment cores were obtained from the south-eastern Caspian coast to identify coastal change driven by water-level changes and to compare the results with other geological and historical findings. The overall results indicate a high-stand during the Little Ice Age, up to −21 m (and extra rises due to manmade river avulsion), with a −28 m low-stand during the Medieval Climate Anomaly, while presently the CSL stands at −26.5 m. A comparison of the CSL curve with other lake systems and proxy records suggests that the main sea-level oscillations are essentially paced by solar irradiance. Although the major controller of the long-term CSL changes is driven by climatological factors, the seismicity of the basin creates local changes in base level. These local base-level changes should be considered in any CSL reconstruction.

Habitat-associated morphological divergence in four Shemaya, Alburnus chalcoides (Actinopterygii: Cyprinidae) populations in the southern Caspian Sea using geometric morphometrics analysis

In this study, Geometric morphometrics approach was used to explore body shape variations and growth trajectory among four population of Shemaya (Alburnus chalcoides). The shape of 114 individuals from three rivers (Lisar, Shiroud and Babolroud) and one lagoon (Anzali) from the south of Caspian Sea was extracted by recording the 2-D coordinates of 16 landmark points. We applied a GPA analysis to eliminate non-shape variations. PCA, CVA, MANOVA and DFA analysis were used to examine shape differences among populations. The significant differences found among the shape of populations. Since Shemaya is an anaderemus fish and all their populations have a common origin, we concluded that differences between habitat features might create selective pressures resulting morphological divergence among conspecific populations. We suggest that high level of plasticity, particularly in the depth of body, head and caudal peduncle shape may reflect low costs of maintaining the plastic response even in relatively isolated populations.

Microseismicity and seismotectonics of the South Caspian Lowlands, NE Iran

This paper is concerned with the microseismicity and seismotectonics of the eastern South Caspian Sea region, where the East Alborz mountains descend to meet the South Caspian Lowlands of NE Iran. To better understand the present-day tectonics and seismicity of this region, which includes the cities of Gorgan and Gonbad-e-Qabus (combined population 500 000), we installed a temporary local seismic network across the area for 6 months between 2009 and 2010. We analysed the seismicity and focal mechanisms together with data from the permanent networks of the Institute of Geophysics, University of Tehran (IGUT) and the International Institute of Earthquake Engineering and Seismology (IIEES), based in Tehran. Microseismicity is focused primarily on the Shahrud fault system, which bounds the east Alborz range to the south. Relatively few earthquakes are associated with the Khazar thrust fault, which bounds the north side of the range. A cluster of shallow microseismicity (<15 km depth) occurs 40 km north of the Khazar fault (within the South Caspian Lowlands; SCL), an area typically thought to be non-deforming. This area coincides with the location of three relatively deep thrust earthquakes (M_w 5.3–5.5) which occurred in 1999, 2004 and 2005. Inversion of teleseismic body waveforms allows us to constrain the depth of these earthquakes at 26–29 km. Although significant sedimentation throughout the SCL obscures any expression of recent fault activity at the surface, focal mechanisms of well-located events from the shallow cluster of micro-seismicity show a significant component of left-lateral strike-slip motion (assuming slip occurs on NE–SW fault planes, typical of active faults in the region), as well as a small normal component. Inversion of traveltimes for well-located events in our network yields a velocity structure for the region, and a Moho depth of 41 km. The pattern of deep thrust and shallow normal seismicity could be explained by bending of the rigid South Caspian crust as it underthrusts the East Alborz mountains and Central Iran. Late Quaternary reorganization of drainage systems in the SCL may be the result of shallow normal fault activity within the SCL.

Morphometric variation among four populations of Shemaya (Alburnus chalcoides) in the south of Caspian Sea using truss network

To analyze the morphometric differentiation among four groups of Shemaya, Alburnus chalcoides (Guldenstadf, 1772), sited in four habitats i.e.: Lisar, Shiroud, Babolroud rivers and Anzali region (southern part of the Caspian Sea), truss network analysis was employed to take multivariate analysis. Truss characters between fourteen selected landmarks on 357 specimens were measured, then allometric method was used to obtain size-adjustment shape data. Multi and univariate analysis of variance revealed significant differences between means of four populations and sexes (P<0.01). In principal component analysis of the shape variations among the populations, the first two components accounted for 50% and 56.6%, of males and females, respectively. The loadings of the first and the second principal components and discriminant functions showed that the differences were located mainly on abdominal, caudal regions and length of fins, indicating to be important in description of the population characteristics. Results indicated that samples of Anzali region were clearly distinct and diverged from other three populations probably because of difference in the habitat condition. Generally female samples showed more morphometric differences than male samples did, but their influence on this issue remained unknown.

Breeding success of Black-crowned Night Heron (Nycticorax nycticorax), Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) (Aves: Ardeidae) in relation to nest height in the South Caspian Sea

Breeding success was investigated in a mixed colony of three species of Ardeidae (Black-crowned Night Heron, Nycticorax nycticorax; Little Egret, Egretta garzetta; and Cattle Egret, Bubulcus ibis) in the Karfestan colony, south Caspian Sea, during the 2006 breeding season. Black-crowned Night Herons occupied higher locations for nesting (4.39 ± 1.44 m) than both Little Egrets (3.07 ± 1 m) and Cattle Egrets (2.8 ± 0.84 m). Clutch size appeared to be independent of the height of the nest from the ground in all species. Mean breeding success was 0.82 ± 0.24, 0.80 ± 0.16 and 0.77 ± 0.17 in the Black-crowned Night Heron, Little Egret and Cattle Egret respectively. Overall breeding success did not vary significantly among the three species. Fledging success and overall breeding success were associated with nest height in the Black-crowned Night Heron, with a tendency for the higher nests to be more successful. Nest height was also correlated with fledging success in the Cattle Egret but had no effect on breeding success in the Little Egret.

Development of spit–lagoon complexes in response to Little Ice Age rapid sea-level changes in the central Guilan coast, South Caspian Sea, Iran

The central Guilan coast along the Iranian Caspian coastline is characterized by sandy beaches and the development of spit–lagoon complexes, which are prone to preserve past sea-level fluctuations. The morphology of three spit–lagoon complexes along the central Guilan coast was studied using ground penetrating radar (GPR) and sediment sequences to understand the effects of past sea-level changes on spit–lagoon development. The results showed the prominent role of coastal setting in conditioning the development of spit–lagoon formation in response to sea-level change. When the Caspian Sea experienced a highstand in the Little Ice Age, the coast of central Guilan recorded fluctuations in sedimentation which are reflected, for example, by river avulsion and beach ridge formation depending on physical setting. In the western half of the central Guilan, eastward longshore currents and strong wave action on a W–E coastline coupled with sea-level changes shaped the Anzali spit–lagoon complex; while in the eastern part of the studied area river avulsion and changing the coastline orientation are responsible for development of the Amirkola and Kiashahr spit–lagoon complexes under the same sea-level fluctuations. Although sea-level change has a major role in spit–lagoon development, an increase in the frequency of storms, changes in sediment supply due to more precipitation, and river avulsion are other players in spit–lagoon development in the central Guilan during the Little Ice Age and more recent times.

Bioaccumulation of Zn, Cu and Mn in the Caviar and Muscle of Persian Sturgeon (Acipenser persicus) from the Caspian Sea, Iran

Concentrations of Zn, Cu and Mn were examined in caviar and muscle of the Persian sturgeon (Acipenser persicus) collected from coastal waters of south Caspian Sea during March and April, 2011. Mean Zn, Cu and Mn concentrations in caviar samples were 21.48, 2.05 and 1.66 μg g(-1) wet weight basis, respectively. The mean Zn, Cu and Mn concentrations in muscle tissues were 7.49, 1.00 and 0.34 μg g(-1) wet weight basis, respectively. The mean concentrations of Zn and Cu in caviar and muscle samples were under the permissible limits proposed by the United Kingdom's Ministry of Agriculture, Fisheries and Food (2000).

Bioaccumulation of Cd, Pb and Zn in the edible and inedible tissues of three sturgeon species in the Iranian coastline of the Caspian Sea

The accumulations of Cd, Pb and Zn were determined in edible and inedible tissues of Persian sturgeon (Acipenser persicus; n=27), stellate sturgeon (Acipenser stellatus; n=5) and beluga (Huso huso; n=4) collected from coastal waters of the South Caspian Sea from March to April 2011. Concentrations of metals evaluated in the caviar, muscle, liver, kidney, gills, ovary and heart of the three species of sturgeons have been assessed using the flame and graphite furnace atomic absorption spectrophotometer. Concentrations of Zn, Pb and Cd in the edible and inedible tissues were apparently different among the three species of sturgeons. Especially, beluga heart showed the highest concentrations of Zn and Pb and Cd in Persian sturgeon liver. The analyzed metals were found in the caviar and muscle samples of Persian sturgeon and likewise muscle samples two other sturgeon species at mean concentrations under the permissible limits proposed by MAFF (2000).

A new species of riffle minnow, Alburnoides holciki, from the Hari River basin in Afghanistan and Iran (Actinopterygii: Cyprinidae)

A new species of riffle minnow, Alburnoides holciki (Cyprinidae), is described from northwestern Afghanistan andnortheastern Iran. It is distinguished from related species by a combination of characters including a well-defined, sharp,scaleless or only slightly scaled ventral keel; a short, slightly pointed snout; a terminal mouth with the tip of the mouthcleft, on a level with the upper half of the pupil; a large eye (orbit width about equal to interorbital width); (46)47–51(55)lateralline scales to posterior margin of hypurals; 2.5–4.2 pharyngeal teeth; usually 8½ branched dorsal-fin rays; usually13–16½ branched anal-fin rays; 40–42, usually 41, total vertebrae; caudal vertebral region longer than abdominal region(most frequent vertebral formulae 20+21, 20+22 and 19+21); and usually 13 or 14 predorsal vertebrae. A comparison withAlburnoides species from rivers of the South Caspian Sea, the northern slope of the Kopetdag Mountains and the Amu Darya basin is provided.