Assessment of habitat suitability index of Capoeta species in the Caspian Sea and Namak Lake basins, Iran

Habitat suitability index (HSI) models are usually used to forecast habitat quality and species distributions and are used to develop biological studies, management priorities and anticipate possible changes under different management or climate change situations. This study was conducted to identify the habitat suitability index of three species namely, Capoeta    buhsei, C.  razii and C. alborzensis in the Kordan, Taleghan and Jajrood Rivers, respectively. At each station, environmental variables including temperature, dissolved oxygen, pH, EC, TDS and hydrological parameters such as flow velocity, depth, width, average diameter of stones and amount of phosphate, nitrate and ammonium were measured. The results showed that suitable habitats for these species are those with a high stone diameter, high temperature, low flow velocity and in areas where the width of the river is low. With respect to the abundance of fishes sampled in this study, the central and lower regions of the Jajrood and Kordan Rivers and the stations far from the dam on the Taleghan River are favorable habitats for the studied Capoeta species.

Histopathological effects of cypermethrin on liver of Aphanius sophiae (Heckel, 1849) using rank-based estimation for linear models

Ecotoxicological studies that use histological techniques enjoy descriptive approach in explaining the damages to tissues. In the present study, a rank-based estimation for linear models was used to examine significant difference between levels of cypermethrin on histological changes of the liver in Aphanius sophiae. The toxicity of cypermethrin associated with certain environmental factors such as salinity and feeding frequency was studied in the Sophiae toothed carp (A. sophiae). Specimens were exposed to concentration of 0.02 μg L-1 cypermethrin, two levels of salinity (0 and 14 ppt) and feeding frequencies (two times a day and one time every three days) under laboratory conditions. After the end of 14 days period of the experiment, the liver tissues were removed and histological sections prepared. The results revealed that liver tissues alter significantly with the changes in salinity and diet frequency. The results also showed that sensitivity to cypermethrin increased with decreasing salinity and increasing feeding frequency. The results suggested using A. sophiae as an indicator for cypermethrin assessment in aquatic ecosystems and appropriateness of rank-based estimation for linear models, to evaluate the effect of toxins on histopathological alternations

Comparison of morphological variations among three species of the genus Paracobitis in Iran using geometric morphometrics method with a taxonomical review on the genus in Iran

This study was conducted to apply the landmark-based geometric morphometrics technique to differentiate three species of the genus Paracobitis (P. iranica, P. malapterura and P. rhadinaeus) in Iran based on their body shape, because previous works, using traditional morphometrics, could not distinct them. A total of 150 specimens were sampled from the Zaringol, Madarsoo, Ghomrood, Kordan Rivers and Chahnimeh reservoir. The left side of the specimens was photographed using a digital camera and then fifteen landmark-points were digitized on two-dimensional images using TpsDig2. Landmark data were analyzed after a generalised procrustes analysis using PCA, CVA and cluster analysis. The patterns of body shape differences among the populations were illustrated in the deformation grids in relation to consensus configuration. The results showed a significant differences among the studied species and their populations in terms of morphological traits (P<0.0001). Some differences were found in the length and depth of head, depth of body, caudal peduncle length and position of eye and position of dorsal fin. The result also showed that P. iranica from Kordan River can be considered to be a distinct taxon compared to the Ghomrood taxon based on its morphological characteristics. In addition, our findings revealed that the geometric morphometrics approach can be a proper tool for morphological and taxonomic studies in species with small sizes including Nemachelinae