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The early morphological development and allometric growth pattern of Caspian kutum (Rutilus frisii kutum) during early development (from 0-35 days post hatch=dph) was studied. Morphological data were obtained using ImageJ software from 2D pictures and allometric growth patterns were computed based on Log10 y = Log10 α + βLog x function. Based on inflexion point of morphological traits and body shape changes, the early developmental of kutum were divided into Eleuthero-embryo, Propterygio-larval, Pterygio-larval” and younger juvenile phases, each of which included vital developmental events. Rapid and intense changes occurred during Eleuthero-embryo and Propterygio-larvae stages such as development of gills, depletion of yolk-sac and exogenous feeding, development of feeding apparatus, sense organs and organs related to swimming performance. The results also revealed that developmental changes occurred in agreement with the inflexion points of morphological characters and their developmental priority imply on functional importance of feeding, respiration and swimming related structures.

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The geometric morphometrics method was applied to study the morphological differences in 95 specimens of Kura barbel (Barbus lacerta, Heckel 1834) collected from three riverine ecosystems of the Sefidrud basin, viz. Taleghan, Totkabon and Kloraz Rivers.  For this purpose, the left sides of the specimens were photographed. Then, 14 Landmark-points were defined and digitized on 2D pictures using Tpsdig2 software. The landmark data, after generalized Procrustes analyzing, were analyzed by PCA, CVA with p-value obtained from permutation test and cluster analysis. The results showed a significant differences between the populations in terms of body shape (P

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The toxicity of cypermethrin at 0.02 μg L^-1 concentration in relation to salinity (0 and 14 ppt) and temperature (16±1 and 25 ± 1°C) was studied on the liver tissue of zebra fish (Aphanius sophiae) exposed to cypermethrin for 14 days under labratory condition. The liver tissue changed significantly with changes in salinity and temperature. The major changes were overlapped hepatocytes, nucleous irregularity, cloudy swelling, atrophy, fat degeneration, pyknosis, focal necrosis, karyolysis, accumulation of kupffer cell, necrosis and bile stagnation. The results showed that sensitivity to cypermethrin increased with decrease in salinity and increase in temperature.This fish is, therefore, not a suitable indicator for cypermethrin assessment in aquatic ecosystems, and if considered as an indicator, the temperature and salinity should also be considered.

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Aims: In the present study, the morphometric and meristic traits of Alburnus chalcoides from the Chelvand (Astara), Khalesara (Talesh), Siahdarvishan (Anzali wetland), Sefid and Pol (Guilan Province), Tonekabon and Babol (Mazandaran Province) rivers were compared.
Materials & Methods: For this purpose, a total of 170 specimens were collected from above-mentioned rivers. In the Lab some 39 morphometric and 10 meristic traits were recorded. All data were analyzed by using One-Way ANOVA, Duncan test, Kruskal-Wallis, principal component analysis (PCA), canonical variate analysis (CVA) and cluster analysis.
Finding: The results showed a significant difference in 36 morphometric and five meristic traits among the studied populations. CVA result separated the studied populations in the southern parts of the Caspian Sea basin. Also, cluster analysis placed the Chelvand River population in a distinct clade. 
Conclusion: This study showed high diversity of morphometric compared to meristic traits and better performance of these traits in population's distinction.

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The present study was conducted in Electric Blue Cichlid Sciaenochromis fryeri in early larval developmental stages from the fifth day post hatching (DPH) until 51 DPH to determine day of transforming from embryo to juvenile. Morphological characteristics were evaluated by using ImageJ software. Allometric growth patterns were calculated based on the formula Y=aX^b. Yolk sac depletion was occurred on day 9. Scales were developed on day 19 and finaly developed juvenile shape. allometric pattern of different body segments were calculated according to isometry, positive, and negative allometry. Positive allometry of head and tail prior to inflexion point and variation in allometric growth pattern in different body segment determine priorities of organogenesis for survival in fish early life history. The obtained results showed consistency between the larval morphological changes and development of organs related to sensory movements and larval behavior. Every morphological change in larvae displays the development and evolution of one of the organs involved in feeding, breathing, swimming and sensory organs.

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In this study, the morphological variation of Oxynoemacheilus bergianus was studied in the different rivers of the Namak Lake and Caspian Sea basins using traditional morphometric method. For this purpose, a total of 76 specimens were collected from eight river systems and after fixation into 4% buffered formalin, transfered to the laboratory, a total of 31 morphological characteristics were measured using digital calipers. After standardization, the morphometric data were analyzed using multivariate analysis including principal component analysis (PCA), canonical variate analysis with p-value obtained from MANOVA (MANOVA/CVA) and cluster analysis (CA). The results showed significant differences in 24 traits between the studied populations (P<0.05), which anal fin depth and the ventral-anal fin distances were main discriminative ones. CVA analysis was able to separate the studied populations. Also, CA placed the Gharesu and Sefid populations in a clade and separate from other populations. The observed differences may be related to phenotype plasticity in response to environmental conditions.

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This study was conducted to investigate the morphological variation of Planiliza abu in the Tireh (Tigris Basin), Kor (Kor River Basin) and Jegin (Hormozgan Basin) rivers using traditional (TM) and geometric morphometric (GM) methods. For this purpose, a total of 62 specimens were collected using electrofishing device and Salik net. In the Lab, 21 morphometric traits were measured. Then, to extract the morphological data in the geometric method, 16 landmark-points were defined and digitized on the photographs taken from the left side of fish using tpsDig2 software. The results showed that the studied populations had significant differences in 7 morphometric traits (P<0.05). The differences in the geometric method were those of the head size, body depth, pectoral fin position and caudal peduncle length. Based on the results, GM method showed higher accuracy to reveal the morphological variations in the generalist species of Planiliza abu, which can inhabit a wide range of habitats.