Age and growth of spirlins, Alburnoides eichwaldii and A. namaki, from the Caspian, Kavir and Namak basins of Iran

چکیده مقاله

Abstract: This study presents data on age structure, sex ratio, growth, length-weight relationships and condition factor of four populations (n=312) of two Alburnoides species, collected in 2005 and 2006 from the Tajan River (Caspian Sea Basin), the Ghara-Chai and Jajrud rivers (Namak Lake Basin), and Cheshmeh-Ali Spring (Kavir Basin) of Iran. Sex ratio of the fish, in the studied localities, except in Jajrud River, was not significantly deviated from the equal sex ratio. The female fish had higher weight, length and condition factor compared to the male fish. The growth pattern of the female fish in Cheshmeh-Ali Spring was isometric, but allometric in other localities. The growth pattern of all male fish, except the ones from Jajrud River, was allometric. The age groups were 0 + -5 + . The prevailing age groups were 0 + , 1 + , 2 + , and 3 + , in Jajrud River, Ghara-Chai River, Tajan River, and Cheshmeh-Ali Spring, respectively. Fish in Jajrud River had higher overall growth performance and K-values, compared to the other populations.