Age structure, growth and mortality index of spirlin (Alburnoides eichwaldii De Filippii 1863) in Shirud River, Mazandaran province

Age structure, growth and mortality index of 661 specimens of spirlin, Alburnoides eichwaldii, from Shirood River in Mazandaran Province were studied during April 2011 to March 2012. The average total length, weight and age of the specimens were 68.33 ± 16.92 mm, 4.9 ± 3.2 g and 1.32 ± 0.86 years, respectively. The fish were in the age range of 0 to 3, of which the 0 year specimens dominanted the age groups in the river. The largest specimen was 111.4 mm in length and a weight of 15.5 g. Comparing total length and weight of fish showed significant differences various ages (P