Size-dependent dietary shifts in Chitala ornata (Osteichthyes; Notopteridae), an accidentally introduced exotic species in Sri Lanka

Food and feeding biology and some morphological adaptation of an exotic fish species Chitala ornata in a riverine habitat in Sri Lanka was studied from March 2003 to July 2004 to investigate its size-dependent dietary shifts. The stomach contents of C. ornata were volumetrically analyzed and relative abundance of different food categories of different length groups was quantified. There is a marked dietary shift from predominantly herbivory during juvenile stage to piscivory at adult stage. Indigenous cyprinid species are prey organisms and as such, C. ornata possibly poses significant negative impacts on native fish populations as well as other aquatic fauna.