Investigation of dam effect of Shahid-Rajaei on variation and differentiation of spirlin (Alburnoides sp.) (Pisces: Cyprinidae) in the Tajan River (Iran)

Effects of Shaheed Rajaee Dam constructed on the Tajan River on diversity and separation of Spirlin (Alburnides sp.) population was studied. Total of 100 fish samples including 50 samples from either side (below and above) of the dam were caught by electrofishing gear and examined. 53 morphometric were measured with the aid of digital clipper and 16 meristic (numerical) characteristics were also determined in all samples. Principal component (PCA) and detrended fluctuation (DFA) and cluster analyses were used to examine morphometric and meristic (numerical) data following standardization (to avoid error related to alometric growth). The one- way ANOVA analysis for standardized morphometric traits revealed statistically significant differences in 27 parameters within specimens which show relatively high phenotype diversity in A. bipunctatus from two studies areas. The DFA analysis showed that fish population in two areas below and above the dam are separated by 93% in morphometric and 78% in meristic characteristics. The PCA analysis also showed that 8 morphometric and 6 meristic characteristic separate fish populations of the river below and above the dam. The dendrogram constructed by UPGMA based on Euclidean distance coefficient also separated the fish population upstream and downstream of the dam.