Massive invasion of resilient exotic fishes in the river Ganga: A case study at Allahabad stretch

Abstract

Due to multifarious stressor operating on the river Ganga, tremendous alteration have been registered in its discharge, velocity, substratum, quality of the abiotic and biotic parameters. Accordingly fishery of the river in general and that of the sensitive species in particular is facing serious threats from loss of habitats, barriers on migratory paths, loss of deep pools, drying of feeding and breeding grounds. Due to these aberrations the fish catch from the river Ganga has been declined, and loss of species diversity has been reported by many workers (Sarkar et al. 2011; Vass et al., 2010; Payne et al., 2004). Further, the deterioration in habitat conditions lead to depletion in sensitive native species and invasive of exotic fishes (Sarkar et al., 2011; Payne et al., 2004). Hence, the present study was carried out to reveal the appearance, invasion and establishment of hardy exotic fishes in the Ganga river system at Allahabad in view of the multiple stressors operating on the river.