Snowflake coral, Carijoa riisei from Grand Island, Goa: a case of invasion of an alien species or re-establishment of a native species?

Invasion is an ecological phenomenon of introduction of organisms to areas outside their native ranges. It concerns all aspects relating to their transport, establishment and spread in a new region . An invasive species causes imbalance to the ecosystem by monopolizing food and spatial resources and consequently disrupting the native community . Biological invasion is presently one of the major sources of stress to the coral reef habitats, which harbour 25% of total marine biodiversity and contribute to 10% of total fishery production .