Exotic species invasion:

Exotic species invasion: Exotic species (non-native; alien) are organisms often introduced unintentionally or deliberately for commercial purpose, as biological control agents and other uses. They often become invasive and drive away the local species and is considered as the second major cause for extinction of species. Exotic species have proved harmful to both aquatic and terrestrial ecosystems. Tilapia fish (Jilabi kendai) ( Oreochromis mosambicus ) introduced from east coast of South Africa in for its high productivity into Kerala’s inland waters, became invasive, due to which the native species such as Puntius dubius and Labeo kontius face local extinction. The illegal introduction of the African catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous cat fishes in our rivers. The introduction of the Nile Perch, a predatory fish into Lake Victoria in East Africa led to the extinction of an ecologically unique assemblage of more than nature species of cichlid fish in the lake.