Feeding regime of Kutum, Rutilus frisii kutum (Kamensky 1901) at the various ages in the southern Caspian Sea (Mazandaran waters) in survey

The feeding habits of Kutum¡ Rutilus frisii kutum (Kamensky 1901)¡ in the southern Caspian Sea (waters Mazandaran) were investigated by examining the stomach contents of fish collected monthly from the commercial and experiment catch from early October 2006 to September 2007. Their diet consisted different prey. Age determination¡ based on scale readings¡ showed that the population was composed of eight age- groups comprise to 1¡2¡3¡4¡5¡6¡7 and 8 years. The highest Index of Fullness (IOF) was occurred in October for female (av.±SD) 313.86±65.9and 350.75 ±103.7 for male. The minimum IOF obtained in March¡ 119.42±59.21 and 144.07± 85.04 percent for female and male¡ respectively which coincided to spawning period. The significant different was between IOF and sex (at the female and male) in various months (ANOVA¡ P