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The Middle East contains a great diversity of Capoeta species, but their taxonomy remains poorly described. We used mitochondrial history to examine diversity of the algae‐scraping cyprinid Capoeta in Iran, applying the species‐delimiting approaches General Mixed Yule‐Coalescent (GMYC) and Poisson Tree Process (PTP) as well as haplotype network analyses. Using the BEAST program, we also examined temporal divergence patterns of Capoeta. The monophyly of the genus and the existence of three previously described main clades (Mesopotamian, Anatolian‐Iranian, and Aralo‐Caspian) were confirmed. However, the phylogeny proposed novel taxonomic findings within Capoeta. Results of GMYC, bPTP, and phylogenetic analyses were similar and suggested that species diversity in Iran is currently underestimated. At least four candidate species, Capoeta sp4, Capoeta sp5, Capoeta sp6, and Capoeta sp7, are awaiting description. Capoeta capoeta comprises a species complex with distinct genetic lineages. The divergence times of the three main Capoeta clades are estimated to have occurred around 15.6–12.4 Mya, consistent with a Mio‐Pleistocene origin of the diversity of Capoeta in Iran. The changes in Caspian Sea levels associated with climate fluctuations and geomorphological events such as the uplift of the Zagros and Alborz Mountains may account for the complex speciation patterns in Capoeta in Iran., Spanish Ministry of Economy and Competitiveness, (Grant/Award Number: “CGL2013-41375-P”).

We evaluated the effects of the Shahid-Rajaei dam, 14 years after its construction, on morphometric and genetic divergence between up- and downstream populations of the Iranian fish Siah-Mahi (Capoeta capoeta gracilis). Sixty-six specimens were analyzed. There were significant differences between the 2 groups in the means of 16 morphometric characters (univariate analysis). In discriminant function analysis, the proportion of individuals classified into their original groups was 97 and 100% for up- and downstream populations, respectively. Principal component analysis of morphometric data demonstrated that the up- and downstream samples of Siah-Mahi are clearly distinct. In the genetic analysis, 6 informative primers produced 89 polymorphic bands with 95% polymorphism. In association analysis between morphological and genetic data, 63 of 89 genetic markers were significantly correlated with the 16 morphometric characters. We conclude that these are 2 morphologically and genetically distinct populations of C. c. gracilis, probably due to limited downstream dispersal and elimination of upstream migration.

It has been postulated that the building of the Shahid-Rajaei dam on the Tajan River around 1995 has lead to the morphological divergence of Siah Mahi Capotes capoeta gracilis (Pisces) of up- and downstream populations due to the isolation. A 13-landmark morphometric truss network system was used to investigate the hypothesis. Univariate analysis of variance showed significant differences between the means of the two groups for 45 standardized morphometric measurements out of 78 characters studied. In linear discriminant function analysis (DFA), the overall assignment of individuals into their original groups was 87.6%. The proportion of individuals correctly classified into their original groups was 90.3% for upstream and 83.7% for downstream population. The principal component analysis (PCA) scatter plot of individual component scores between PC1 and PC2 showed 121 fish specimens grouped into two areas but with a relativity high degree of overlap between two populations. Clustering analysis based on Euclidean square distances among groups of centroids using an UPGMA resulted into two main clusters indicating two populations of C. c. gracilis. The present study indicated the presence of two morphologically different populations of C. c. gracilis in the Tajan River across the Shahid-Rajaei dam, probably due to their limited downstream dispersal and the elimination of upstream migration altogether, due the construction of the dam.

In the present study, 81 specimens of Capoeta capoeta gracilis (Keyserling, 1861) were collected from the Shiroud River, the Caspian drainage basin, Iran in June and October 2007. The fish were examined for infection with the nematode Rhabdochona fortunatowi (Dinnik, 1933). Nematodes were counted and sexed, then the sex ratio and intestinal site preference of the R. fortunatowi individuals and the intersexual interactions of the parasites were investigated. Significant differences were observed in the prevalence and intensity of infection in relation to host size and sampling season, but not host sex. Parasite burden (mean intensity) was higher in October than in June and the results revealed a decrease in female-to-male sex ratio (FMR) in the fish in October compared to the ones in June. In other words, as the mean intensity of infection of R. fortunatowi increases, the proportion of male worms increases, too. The female-biased sex ratio in June was replaced by a male-biased one in October. Nematode distribution rose to a significant peak in the mid-region of the fish intestine relative to the anterior and posterior parts. Some changes in the distribution of male and female worms in different parts of the host intestine were also observed during June and October. Density-dependent selection and intersexual competition seem to be the main factors driving such a shift in the sex ratio and its variation in different parts of the host intestine.

Summary Siah Mahi, Capoeta capoeta gracilis, is a predominant fish in the river systems of the south Caspian Sea basin. Although there is evidence of the geographical divergence of this taxon, no information is available on morphological differences within the subspecies populations. The study was designed to evaluate this differentiation in the Shirud River system of the south Caspian Sea basin in Iran. A total of 120 fish specimens (≥ 180 mm) were collected from the Shirud River; 33 morphometric and 10 meristic characteristics were recorded for each specimen. The standardized data were subjected to a principal component analysis (PCA) and variables with eigenvector ≥ 0.74 used as input for analysis of clustering, which grouped the 120 fish specimens into five distinct clusters. The overall random assignment of individuals into their original groups was high (86.7%), indicating that these specimens are highly divergent from each other. The proportion of individuals correctly classified into their original groups was 90, 81.8, 85.7, 100 and 76% for groups 1, 2, 3, 4 and 5, respectively. There were significant differences in nine morphometic characteristics among the five multivariate groups. Pectoral-anal length was the only characteristic that, based on all possible pair combinations of the five groups, could be individually distinguishable. With regard to meristic characteristics, a Kruskal–Wallis test showed that there were no significant differences among medians of the five multivariate groups.

Karasu River, which is the only river in the Erzurum plain, is the source of the Euphrates River (Eastern Anatolia of Turkey). The river is in a serious environmental situation as a result of pollution by agricultural and industrial sewage and domestic discharges. The present study aims to evaluate genotoxic effects of toxic metals in chub, Leuciscus cephalus, and transcaucasian barb, Capoeta capoeta, collected from contaminated site of the Karasu River, in comparison with fish from an unpolluted reference site. Heavy metal concentrations in surface water of the river were determined. The condition factor (CF) was taken as a general biomarker of the health of the fish, and genotoxicity assays such as micronucleus (MN) and other nuclear abnormalities (NA) were carried out on the fish species studied. MN and NA such as kidney-shaped nucleus, notched nucleus, binucleated, lobed nucleus, and blebbed nucleus were assessed in peripheral blood erythrocytes, gill epithelial cells, and liver cells of the fish. A significant decrease in CF values associated with a significant elevation in MN and NA frequencies was observed in fish collected from the polluted sites compared with those from the reference site. Results of the current study show the significance of integrating a set of biomarkers to identify the effects of anthropogenic pollution. High concentrations of heavy metals have a potential genotoxic effects, and the toxicity is possibly related to industrial, agricultural, and domestic activities.

Summary It is believed that streams of a basin may contribute to stream-specific variation in allometry coefficients related to between-habitat differences. To test intra-basin variation of the allometry coefficients of Lenkorn Capoeta capoeta gracilis (Keyserling, 1861), a total of 1731 individuals were sampled in six streams of the Gorganroud basin (southeast Caspian Sea) between April and May 2008. Values of b ranged from 2.647 for males of Chelchai to 2.964 for females of Madarsou, indicating negative allometric growth for the fish in the basin. There were variations in the allometry coefficient among the considered groups, which can be interpreted as species’ response to different habitats. To the best knowledge of the authors, this study documents the comparative reference on variation of allometry coefficient of Capoeta capoeta gracilis in southeast Caspian streams.

Investigation of habitat conditions and identification of aquatic species in running waters is of high importance in ecological research. This study was carried out in Aras River on the eastern side of the Azerbaijan province from Jolfa to Aslandooz in 2005-2006. Fish sampling was carried out in seven stations seasonally by an electro shocking instrument. During the sampling, important water parameters including EC, TDS, DO, CO _ (2), pH, alkalinity and hardness were also recorded. Biometrical evaluations on 1365 prey fish showed that 17 species and subspecies belonging to 6 families, Cyprinidae, Balitoridae, Cobitidae, Siluridae, Percidae, Gobiidae were present in the samples. Cyprinidae family was represented by 12 species and subspecies and other fish families had only one representative. Capoeta capoeta with 56.6% had the highes t frequency and was the most dispersed compared to other species in Aras River.

Makoo dam lake made up in 1998, to providing agriculture water, prevention of flood water and production of electric power. It is placed in 12 km to south of Makoo city 29° 44' minute E and 39°11' N). Feeding studies occurred by using of fishing gear, include of electro fishing, gill net and beach seine, seasonally. Fish caught was in size range of 27-290 mm and 0.4- 327.7g. Maximum and minimum of feeding intensity was in winter and spring, respectively. Its average was 360, that showed feeding of this fish was approximately optimum in this lake. Whereas maximum and minimum of K-factor was in summer and winter, respectively. C. capoeta is a detritovorous. Therefore, it consumed from so much other food items, a.g. phytoplankton and benthos in this lake. From phytoplankton, phylum Chrysophyta and genus cyclotella from benthos; Chirooomidae and Ephemeroptera have the most important food sources. With attention to limitation of food organisms of benthos, it is not recommended introducing of other benthopelagic fishes in Makoo lake.

The objective of this survey, carried out from March to December 1994, was to study the composition of the fish fauna in Babolrud River, connected to the southern part of the Caspian Sea. The fishes were caught using a electroshocker device from 5 stations allocated to this purpose along the river. The obtained data from this survey indicated that the fish fauna of Babolrud River is comprised of 7 families. Family Cyprinidae with 15 species, including Capoeta capoeta and Carassius auratus, the two dominant species in the river, was the most abundant family compared to the other identified families (Balitoridae, Cobitidae, Gobiidae, Esocidae, Mugilidae and Petromyzontidae) represented only with one species each. The 67% of the fishes in Babolrud River are resident......