Discrimination of populations of Caspian Roach (Rutilus rutilus) using trace element content in otoliths

Otoliths were collected from 98 Caspian Roach in the east, center and west parts of south Caspian Sea during 1999-2000. Trace elements K, Sr, Cu, Fe, Zn, and Br in the otoliths were detected using PIXE method. Our results suggest K, Sr, Cu, Fe, and Zn can be used as discriminating factors for population separation in Caspian Roach. The value of K, Sr, Cu, Fe, and Zn were 7.1, 178.3, 0.1, 2.6, 0.3ppm in the west and 9.5, 11.1, 0.3, 5.7, 0.2ppm in the east. Therefore, Caspian Roach from west and east can be discriminated based on their significantly different concentration of trace element contents (p<0.05). However, this was not the case for fish from central part and Anzali area (p<0.05). This study affirmed earlier results from investigations on morphometric characteristics of Caspian Roach suggesting the presence of two different populations of Rutilus rutilus in the south of the Caspian Sea, namely Anzali-Kura, and Gorgan-Turkmen.