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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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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.

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Malathion and diazinon are widely used organophosphate pesticides in the agriculture fields, especially in the north provinces of Iran. In the current study, lethal concentrations of diazinon and malathion were determined based on big head carp calculated death rates at 24, 48, 72 and 96 hours using probit analysis. Then, in a separate experiment and according to the obtained LC₅₀, the effects of these toxins on fish hematological parameters was evaluated in which fish were disturbed in 10 treatments with 3 replicates (4 different doses of diazinon, 4 different doses of malathion and 1 control for each toxin) for 7 days. Fish were exposed to different sub-lethal concentrations of each toxin (12.5, 25, 37.5 and 75% of lethal concentration (LC50 96h). After 7 days, blood samples were collected and hematological parameters including hematocrit, hemoglobin, red blood cells count, the total number of white blood cells and white blood cell differential count (the percentage of lymphocytes, monocytes, neutrophils and eosinophils) were examined. The results of acute toxicity test showed that diazinon is more toxic to big head carp compared to malathion. Also, hematological studies of big head carp exposed to diazinon showed a significant reduction in red blood cells and white blood cells with increasing toxin concentration. Meanwhile, the percentage of neutrophils remarkably increased while lymphocytes significantly decreased along with increasing the concentration of diazinon.